Amoco - Directional Survey Handbook by NED SPE STUDENT CHAPTER

Upstream Technology Group

ISSUE 1 SEPTEMBER 1999

BP Amoco Directional Survey Handbook

BPA-D-004

Contents Authorisation for Issue Preface Amendment Summary

Section 1

Section 2

Section 3

Section 4

Introduction 1.1

About this Handbook

1.2

Directional Survey and Value Addition

1.3

The Design-Execute Principle

Policy and Standards 2.1

Drilling and Well Operations Policy

2.2

Policy Expectations

2.3

Standard Practices

Theory 3.1

Surface Positioning

3.2

The Earth’s Magnetic Field

3.3

Position Uncertainty

3.4

Position Uncertainty Calculations

Methods 4.1

Multi-Well Development Planning

4.2

Survey Program Design

4.3

Anti-Collision – Recommended Practice

4.4

Anti-Collision – Selected Topics

4.5

Target Analysis

4.6

Survey Calculation

4.7

In-Hole Referencing

4.8

In-Field Referencing

4.9

Drill-String Magnetic Interference

4.10 Survey Data Comparison

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Contents (contâ&#x20AC;&#x2122;d) Section 5

Survey Tools 5.1

Inclination Only Tools

5.2

Measurement While Drilling (MWD)

5.3

Electronic Magnetic Multishots

5.4

North-Seeking and Inertial Gyros

5.5

Camera-Based Magnetic Tools

5.6

Surface Read-Out Gyros

5.7

Dipmeters

5.8

Obsolete and Seldom Used Tools

5.9

Depth Measurement

5.10 JORPs

Section 6

Technical Integrity 6.1

What is Technical Integrity ?

6.2

Risk Assessment

6.3

Surface Positioning

6.4

The Directional Design

6.5

Executing the Design

6.6

Survey Data Management

6.7

Performance Review

Appendix A

Mathematical Reference

Appendix B

Approved Tool Error Models

Appendix C

Data and Work Sheets

ii Introduction

September 1999 Issue 1

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Preface This Issue 1 of the BP Amoco Directional Survey Handbook (BPA-D-004) is applicable in all areas of the BP Amoco organisation. In addition to the uncontrolled hard copies, this document is also available online via the wellsONLINE and ASK websites, accessible on the BP Amoco Intranet. The online document is to be considered the master version, containing the most up-to-date information. The distribution of this document is managed by the Upstream Technology Group (UTG) and controlled and administered in Aberdeen by ODL. ODL may be contacted as follows: UTG DCC or: ODL Buchanan House 63 Summer Street Aberdeen AB10 1SJ Scotland

UTG DCC ODL Mailbox BP Amoco, Dyce (through internal mail)

Tel 44 (0)1224 628007 Fax 44 (0)1224 643325 Alternatively, contact the UTG Wells Document Controller, Steve Morrison at BP Amoco, Dyce, Extn 3593 (44 (0)1224 833593

September 1999 Issue 1

v/vi

BP Amoco Directional Survey Handbook

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Amendment Summary Issue No

Date

Issue 1

Sept 1999

September 1999 Issue 1

Description First issue of document.

vii/viii

BP Amoco Directional Survey Handbook

BPA-D-004

Section 1

Contents

Page

1-1

1-2

! " #

1-6

Well positioning process and associated files

1-7

Figure 1.1

September 1999 Issue 1

Introduction 1-i/ii

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BPA-D-004

Who this Handbook is for, and what itâ&#x20AC;&#x2122;s about.

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September 1999 Issue 1

Reference to another section in the Handbook

Reference to a technical paper or publication Indicates a BP Amoco Standard Practice

Introduction 1-1

BP Amoco Directional Survey Handbook

BPA-D-004

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1-2 Introduction

September 1999 Issue 1

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* &

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The wellâ&#x20AC;&#x2122;s surface position must be directly above or at a known horizontal offset from the geological target located by the seismic survey, often taken months or years before. 1 " # % % $ " " " 3 & ' $ " # % "" % % # 3 $ & 0 " # # # # " # $ " & 0 # $

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September 1999 Issue 1

Introduction 1-3

BP Amoco Directional Survey Handbook

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The wellbore must not hit any existing wells which lie between it and the target. " " # ; " 5 $ # % # " &

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1-4 Introduction

September 1999 Issue 1

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September 1999 Issue 1

Introduction 1-5

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# $ Examining any question or decision about well positioning against this principle is almost guaranteed to help in its resolution. The purpose and content of the Directional Design and Well Survey Files are explained in Sections 6.4 and 6.6

1-6 Introduction

% & '

( ) ) *

September 1999 Issue 1

BP Amoco Directional Survey Handbook

Identify geological target(s)

Directional Design File Well Location Memorandum

BPA-D-004

Formalise well objectives and planned surface and target locations

Well Survey File

Well Data Pack or similar

Final Well Position Memo Position rig at surface location

Final proposed trajectory and survey program Acquire and validate survey data per program

Compile definitive well survey and load to database

September 1999 Issue 1

Design directional plan and survey program

Figure 1.1 Well positioning process and associated files

Survey reports

Defintive well survey

Introduction 1-7/8

BP Amoco Directional Survey Handbook

BPA-D-004

Section 2

" Contents

Page

3 $# "

2-2

" !#

2-3

2-9

September 1999 Issue 1

Policy and Standards 2-i/ii

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" What BP Amoco Policy says about directional surveying and what it means for your Business Unit.

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Policy and Standards 2-1

BP Amoco Directional Survey Handbook

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September 1999 Issue 1

BP Amoco Directional Survey Handbook

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(12.5) A database of well trajectories (planned and actual) and all project data (slots, targets, locations and projections) shall be maintained in a form approved by a qualified person appointed by BP Amoco Senior Drilling Manager. This safety-critical database shall be the subject of a written plan approved by BP Amoco that describes how it shall be managed throughout the Business Unit life cycle. ,&, 1 0 $ # $ "= â&#x20AC;˘ ) â&#x20AC;˘ ) " $ "

September 1999 Issue 1

Policy and Standards 2-3

BP Amoco Directional Survey Handbook

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(8.4) The final position of all spud locations shall be confirmed by a qualified surveyor. (8.8) The rotary table elevation, relative to seabed at mean sea level and water depth (offshore drilling units) or the rotary table elevation relative to ground level (land drilling rigs) shall be determined and formally recorded.

2-4 Policy and Standards

September 1999 Issue 1

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A&, 9 $ # % " # # " ) 6 0 & A&A ' " # " 5 $ " 5 % " " # & ' " " "

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September 1999 Issue 1

Policy and Standards 2-5

BP Amoco Directional Survey Handbook

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" )

(12.1) Survey programs for all wellbores shall be designed such that the wellbore is known with sufficient accuracy to: a) Meet local government regulations b) Penetrate the geological target(s) set in the wellâ&#x20AC;&#x2122;s objectives c) Minimise the risk of intersection with any nearby wellbore d) Drill a relief well (12.2) The performance specification of all instruments employed on operations shall be approved for the use by a qualified person appointed by BP Amoco Senior Drilling Manager. ?&, 1 $ $ # $ $ 8 & ?&A + " #

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2-6 Policy and Standards

September 1999 Issue 1

BP Amoco Directional Survey Handbook

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(12.6) On multi-well operations a collision check shall be performed on the planned well trajectory (12.7) All procedures for assessing tolerable risks of collision, defining minimum well separations and ensuring compliance with such criteria while drilling shall be approved by a qualified person appointed by BP Amoco Senior Drilling Manager. 9 5 " $ &?& 9 % 3 " &? # # & &, $ # # $ & &A # " # 8 # " $ " "&

September 1999 Issue 1

Policy and Standards 2-7

BP Amoco Directional Survey Handbook

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2-8 Policy and Standards

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September 1999 Issue 1

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September 1999 Issue 1

Policy and Standards 2-9

BP Amoco Directional Survey Handbook

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2-10 Policy and Standards

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Section 3

Contents

Page

' "

5 1 +

3-17

" (

3-21

" ( &

3-26

3-1

Figure 3.1

The Earthâ&#x20AC;&#x2122;s surface and the geoid

3-2

3.2

Globally and locally fitting ellipsoids

3-3

3.3

Dependence of latitude on choice of ellipsoid and datum

3-3

3.4

Relationship between geodetic heights

3-5

3.5

Geographical, mapping grid and drilling grid co-ordinates

3-7

3.6

Variation of grid scale factor across a mapping grid

3-8

3.7

Components of the magnetic field vector

3-18

3.8

The one dimensional normal distribution

3-23

3.9

A two dimensional distribution resolved in two directions

3-24

3.10

Principal directions and the standard error ellipse

3-25

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Theory 3-i

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Section 3

Contents (contâ&#x20AC;&#x2122;d)

Table 3.1 3.2 3.3 3.4 3.5

Page Definition of the drilling grid in some BP Amoco operation areas

3-9

The magnetic field in some of BP Amocoâ&#x20AC;&#x2122;s operating areas (approximate values as of 1 July 1999)

3-19

Confidence intervals for the one dimensional normal distribution

3-23

Confidence intervals for the two dimensional normal distribution

3-25

Error term propagation modes

3-27

3-ii Theory

September 1999 Issue 1

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An introduction to the science of well surveying.

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September 1999 Issue 1

Theory 3-1

BP Amoco Directional Survey Handbook

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Mountain Range

Geoid Figure 3.1

The Earth

The Earthâ&#x20AC;&#x2122;s surface and the geoid

Ocean

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3-2 Theory

September 1999 Issue 1

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globally fitting ellipsoid

geoid

eg. WGS 84

Figure 3.2 Globally and locally fitting ellipsoids area of best fit of ellipsoid to geoid

locally fitting ellipsoid eg. Clarke 1866

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EQUATOR

September 1999 Issue 1

Point

perpendicular to black ellipsoid black latitude

grey latitude

Figure 3.3 Dependence of latitude on choice of ellipsoid and datum

Theory 3-3

BP Amoco Directional Survey Handbook

BPA-D-004

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3-4 Theory

September 1999 Issue 1

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September 1999 Issue 1

Theory 3-5

BPA-D-004

BP Amoco Directional Survey Handbook

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3-6 Theory

September 1999 Issue 1

BP Amoco Directional Survey Handbook

mapping grid

BPA-D-004

drilling grid

West of the Central Meridian, grid convergence is negative

lines of latitiude and longitude East of the Central Meridian, grid convergence is positive

Figure 3.5 Cross-section shown in figure 3.6

Geographical, mapping grid and drilling grid co-ordinates

Central Meridian

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September 1999 Issue 1

Theory 3-7

BP Amoco Directional Survey Handbook

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3-8 Theory

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3 " % "

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Structure Centred Referencing Survey Reference = True North

drilling grid north (DGN) drilling datum (= rotary table) TRUE NORTH

structure ref. point

(MAPPING) GRID NORTH

DGN

Norway UK - Forties UK - Magnus UK - former Amoco

Well Centred Referencing Survey Reference = True North

USA - Alaska

Table 3.1

DGN

Structure Centred Referencing Survey Reference = Grid North

Definition of the drilling grid in some BP Amoco operating areas

UK - former BP (excluding Forties, Magnus) Netherlands

DGN

Well Centred Referencing Survey Reference = Grid North

USA - Gulf Coast USA - Land Colombia

September 1999 Issue 1

Theory 3-9

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3-10 Theory

September 1999 Issue 1

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September 1999 Issue 1

Theory 3-11

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September 1999 Issue 1

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September 1999 Issue 1

Theory 3-13

BPA-D-004

BP Amoco Directional Survey Handbook

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3-14 Theory

September 1999 Issue 1

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September 1999 Issue 1

Theory 3-15

BP Amoco Directional Survey Handbook

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Section 4.2 gives the surveying requirements for relief well contingency

3-16 Theory

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September 1999 Issue 1

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September 1999 Issue 1

Theory 3-17

BP Amoco Directional Survey Handbook

BPA-D-004

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3-18 Theory

September 1999 Issue 1

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1 " # $ $ 5 " $ " " ! 8 $ & 1 $ " ; " % #

$ "" " $ $& Long.

Declination

Dip Angle

Field Intensity

Horizontal Intensity

8Â°N

109Â°E

0Â°

41,000 nT

Abu Dhabi

24Â°N

54Â°E

1Â°E

36Â°

43,000 nT

34,000 nT

Egypt

28Â°N

33Â°E

3Â°E

41Â°

42,000 nT

32,000 nT

Kuwait

29Â°N

48Â°E

3Â°E

44Â°

44,000 nT

32,000 nT

Algeria

29Â°N

1Â°E

2Â°W

39Â°

40,000 nT

31,000 nT

Trinidad

10Â°N

61Â°W

14Â°W

34Â°

34,000 nT

28,000 nT

Colombia

5Â°N

73Â°W

6Â°W

31Â°

33,000 nT

28,000 nT

Azerbaijan

40Â°N

50Â°E

5Â°E

58Â°

49,000 nT

26,000 nT

USA â&#x20AC;&#x201C; Gulf Coast

28Â°N

88Â°W

0Â°

59Â°

48,000 nT

25,000 nT

Bolivia

17Â°S

62Â°W

9Â°W

-11Â°

24,000 nT

23,000 nT

Argentina â&#x20AC;&#x201C; Austral

54Â°S

66Â°W

12Â°E

-50Â°

32,000 nT

21,000 nT

UK â&#x20AC;&#x201C; Wytch Farm

50Â°N

2Â°W

4Â°W

65Â°

48,000 nT

20,000 nT

UK â&#x20AC;&#x201C; Central N. Sea

57Â°N

1Â°E

4Â°W

71Â°

50,000 nT

17,000 nT

Canada â&#x20AC;&#x201C; Alberta

55Â°N

114Â°W

20Â°E

77Â°

59,000 nT

13,000 nT

Norwegian Sea

65Â°N

7Â°E

2Â°W

75Â°

52,000 nT

13,000 nT

USA â&#x20AC;&#x201C; Alaska

70Â°N

147Â°W

29Â°E

81Â°

57,000 nT

9,000 nT

Location

Vietnam

Lat.

Table 3.2 The magnetic field in some of BP Amocoâ&#x20AC;&#x2122;s operating areas (approximate values as of 1 July 1999)

0 ) +

. * ! " % $ " 5 " = 1 , + .

1 " $ * ! " 5 LET " " $ * ! " & $ # # & ' . % " $ " 1 " $ &

September 1999 Issue 1

Theory 3-19

BP Amoco Directional Survey Handbook

BPA-D-004

0 1 & ! / 2!.

1 " & 9 $ $ $& 6 " # & 1 " % # " " # 1 &

. &1 '02 / 2!.

1 "

" # $ $ %

$ & ' " " & $ $ % " " " # 1 . % % $ " $ $ & 1 "" " $ $ " B&A "" $ $ " " $ &E & 0 ) 1

BP Amoco Standard Practice

3-20 Theory

$ % " % "

& 1 " " # " : " " $& ' / $ / / $ 0 (( " $ " $ " % & 1 //0

/ " " & '/49 ' / $ 4 " 9 % B % !

September 1999 Issue 1

BP Amoco Directional Survey Handbook

BPA-D-004

" (

" # & 1 " # "

$ # % " & 1 " #

% % 3 & # % # # & 9 5 % â&#x20AC;˘ ) $ ; # % " # " & 1 â&#x20AC;˘ ) $ $ $ & " $ % " # " $ " & 1 # " $ % # & ( $ )

9 % # " = 1

& & Ď&#x192;% $ "

" 3 " $ 3 "" # & 1 " " # $ # " ,&C,& . " " -ET " : " &

September 1999 Issue 1

Theory 3-21

BPA-D-004

BP Amoco Directional Survey Handbook

'" # ( U $ % O(%UP 3 & 5 % OBV?W%-VBWP $ LBT " " 2 & ' " 5 " " " " & 1 O Ď&#x192;%GĎ&#x192;P O AĎ&#x192;%GAĎ&#x192;P # " $ ?&E& 1 , $ A $ , A " & 1

" # & ' " $ % " -B& T L-&-T& $, 1 , $, . ,$*1 . * -( $,

9 $ % / "

& 1 # Âľ Ď&#x192; 2 " Ď&#x192; " = ďŁą â&#x2C6;&#x2019; (x â&#x2C6;&#x2019; Âľ ) ďŁź 1 f (x ) = exp ďŁ˛ ďŁ˝ 2 Ď&#x192; 2Ď&#x20AC; ďŁł 2Ď&#x192; ďŁž 2

1 " # $ " $ # , $ A $ " " & 1 -E&?T LB& T " # " # &

3-22 Theory

September 1999 Issue 1

BP Amoco Directional Survey Handbook

BPA-D-004

f(x) 0.4 0.35 0.3 0.25

Figure 3.8

95.4% confidence interval

0.2

The one dimensional normal distribution

0.15 0.1

-2 Ď&#x192;

0.05

-1 Ď&#x192;

68.3% confidence interval

+1 Ď&#x192;

+2 Ď&#x192;

0 -3.0

-2.5

-2.0

-1.5

-1.0

-0.5

0.0

+0.5

+1.0

+1.5

+2.0

+2.5

+3.0

LBT " " # % 3 A $ & 1 " ? $ # % 5 " $ T # 5 & B T " $ $ & ' # % 3 7G> A $ K LBT " !

3 5 & +

" " = confidence level

standard deviations

confidence level

standard deviations

confidence level

standard deviations

25%

Âą 0.32

80%

Âą 1.28

95%

Âą 1.96

50%

Âą 0.68

85%

Âą 1.44

98%

Âą 2.33

75%

Âą 1.15

90%

Âą 1.65

99%

Âą 2.58

September 1999 Issue 1

Table 3.3 Confidence intervals for the one dimensional normal distribution

Theory 3-23

BP Amoco Directional Survey Handbook

BPA-D-004

f(x) 0.4 0.35 0.3 0.25

Figure 3.8

95.4% confidence interval

0.2

The one dimensional normal distribution

0.15 0.1

-2 Ď&#x192;

0.05

-1 Ď&#x192;

68.3% confidence interval

+1 Ď&#x192;

+2 Ď&#x192;

0 -3.0

-2.5

-2.0

-1.5

-1.0

-0.5

0.0

+0.5

+1.0

+1.5

+2.0

+2.5

+3.0

LBT " " # % 3 A $ & 1 " ? $ # % 5 " $ T # 5 & B T " $ $ & ' # % 3 7G> A $ K LBT " !

3 5 & +

" " = confidence level

standard deviations

confidence level

standard deviations

confidence level

standard deviations

25%

Âą 0.32

80%

Âą 1.28

95%

Âą 1.96

50%

Âą 0.68

85%

Âą 1.44

98%

Âą 2.33

75%

Âą 1.15

90%

Âą 1.65

99%

Âą 2.58

September 1999 Issue 1

Table 3.3 Confidence intervals for the one dimensional normal distribution

Theory 3-23

BP Amoco Directional Survey Handbook

BPA-D-004

( % )

9 $ ?&L " # ; $ %

$ "" # & $ " % # $ " $ & ' " $ % " . * & North

Figure 3.9 A two dimensional distribution resolved in two directions

East

% # # " 5 & ' # # & 1 # 5 # 3 $ " $ , $

" & 1 # " # $ " $ &

3-24 Theory

September 1999 Issue 1

BP Amoco Directional Survey Handbook

BPA-D-004

direction of maximum variation

North

Ď&#x192;max standard error ellipse

Figure 3.10 Principal directions and the standard error ellipse

Ď&#x192;min

direction of minimum variation

East

' # " % " # " & 9 " # % # " & 9 % " $ " " $ " " "

& 9 5 % A& B $

% # 5 3 A& BĎ&#x192; max A& B Ď&#x192; min % LBT " $ " & + = confidence level

standard deviations

confidence level

standard deviations

confidence level

standard deviations

25%

0.76

75%

1.67

95%

2.45

39.3%

1.00

86.5%

2.00

98.9%

3.00

50%

1.18

90%

2.15

99%

3.03

September 1999 Issue 1

Section A.2 includes more details on the mathematics of position uncertainty, including how to calculate other values for Table 3.4.

Table 3.4 Confidence intervals for the two dimensional normal distribution

Theory 3-25

BP Amoco Directional Survey Handbook

BPA-D-004

" ( &

1 # #

# & ' % $ " # $ &A " # " 3 $ & 1 # # $ " " # &

For a full description of the method, see

" " & # % " $ "

1 " " $ = â&#x20AC;˘ *

# â&#x20AC;˘ " $ % ; â&#x20AC;˘ *

" ""

â&#x20AC;˘ 1 # ; "

$ $ # â&#x20AC;˘ 1 "" # "

3 " ""

3-26 Theory

September 1999 Issue 1

BP Amoco Directional Survey Handbook

BPA-D-004

' #

& ""

& ' " " # $ = â&#x20AC;˘ % $& 7

â&#x20AC;˘ # $ $ " % $ "" "

â&#x20AC;˘ ; % 5 "

â&#x20AC;˘ $ 3 â&#x20AC;˘ "" Ď ,% Ď A Ď ? $

# % # % " 1

! : # ! "" # # & 1 " = Propagation Mode

Ď 1

Ď 2

Ď 3

mean

0 1 1 1 1

0 0 1 1 1

0 0 0 1 1

0 0 0 0 â&#x2030; 0

Random Systematic Per-Well Global Bias

# "

$ " $ "

# "" &

September 1999 Issue 1

Table 3.5 Error term propagation modes

Appendix B contains a list of the current BP Amoco approved error models.

Theory 3-27

BP Amoco Directional Survey Handbook

BPA-D-004

& "

" " # $ =

â&#x20AC;˘ " :

$ $ $ " â&#x20AC;˘ # 8 % & " â&#x20AC;˘ # " 8 $ %

$ â&#x20AC;˘ "

Section A.2 describes the interpretation and manipulation of position covariance matrices.

, & & "

& 1 $ " $ & 1 " " % ?Ă&#x2014;? 5% & -

3 $ % # " ; & # $ "

# # &

& % " % 5& " #

; % $ $ % & *5 5 $ " # ; " ;

# $ & 1

$ " # % % $ "

% #

% % $ " 5 "

3-28 Theory

September 1999 Issue 1

BP Amoco Directional Survey Handbook

BPA-D-004

1 "" "

" # # " # & 1 " # $ "" = â&#x20AC;¢ *

# â&#x20AC;¢

! $ # $ $ $ â&#x20AC;¢ + $ % $ " $ #

1 # # " # = â&#x20AC;¢ 1 " # & ' $

$ !

â&#x20AC;¢ 1 # # $ $ & ' $

$ !

â&#x20AC;¢ 1 "" $ # % " % "

September 1999 Issue 1

Theory 3-29/30

BP Amoco Directional Survey Handbook

BPA-D-004

Section 4

1 Contents

Page 4

1 3 #) "

4-1

" )

4-6

& 9 * )) "

4-17

4 4

& 9 #

4-27

4 :

4-34

4 ;

4-39

4 <

* '

4-40

4 =

+ * '

4-48

4 >

1 '

4-55

4 ?

& )#

4-59

4.1

A well planned development

4-3

4.2

A poorly planned development

4-5

4.3

Flowchart for survey program design

4-7

4.4

Schematic of a relief well

Figure

September 1999 Issue 1

4-10

Methods 4-i

BP Amoco Directional Survey Handbook

BPA-D-004

Section 4

1 Contents (contâ&#x20AC;&#x2122;d)

Figure

Page

4.5

The minimum separation rule for major risk wells

4-18

4.6

How a nearby offset well appears on a travelling cylinder

4-27

4.7

Travelling cylinder co-ordinates

4-29

4.8

Rules and conventions for drafting tolerance lines

4-30

4.9

Principle of single wire magnetic ranging

4-32

4.10

Calculation of the drillerâ&#x20AC;&#x2122;s target

4-35

4.11

Calculation of the drillerâ&#x20AC;&#x2122;s target (contd.)

4-36

4.12

Effect of hole angle on size of drillerâ&#x20AC;&#x2122;s target (side-on view)

4-37

4.13

Drillerâ&#x20AC;&#x2122;s target volume for a horizontal well

4-38

4.14

Pinched-out drillerâ&#x20AC;&#x2122;s target â&#x20AC;&#x201C; a case for geosteering

4-39

4.15

In-hole referencing â&#x20AC;&#x201C; section drilled with multiple BHAs

4-42

4.16

In-hole referencing â&#x20AC;&#x201C; section drilled with single BHA

4-45

4.17

The IIFR principle

4-48

4.18

Typical process sequence in an IIFR operation

4-51

4.19

Typical data flow in an IIFR operation

4-54

4.20

Estimating magnetic axial interference

4-56

4.21

The principle of simple axial interference corrections

4-57

4.22

A Survey T-Plot

4-60

4-ii Methods

September 1999 Issue 1

BP Amoco Directional Survey Handbook

BPA-D-004

Section 4

1 Contents (contâ&#x20AC;&#x2122;d)

Table

Page

4.1

Required competencies for anti-collision work

4-19

4.2

Calculation of in-hole reference corrections â&#x20AC;&#x201C; section drilled with multiple BHAs

4-44

Calculation of in-hole reference corrections â&#x20AC;&#x201C; section drilled with a single BHA

4-46

Maximum acceptable axial magnetic interference corrections, by region

4-58

Forbidden hole directions for axial magnetic interference corrections

4-58

4.6

Rules-of-thumb when using the error ellipse method

4-61

4.7

Quantitative interpretation of the error ellipse method

4-62

4.8

Example of a Relative Instrument Performance analysis for azimuth differences

4-64

Rules-of-thumb for use with Relative Instrument Performance analyses

4-65

4.3 4.4 4.5

4.9

September 1999 Issue 1

Methods 4-iii/iv

BP Amoco Directional Survey Handbook

BPA-D-004

Mathematical, logical and procedural tools for optimum well positioning.

$ $ " # $& 0 " % " " " " # % 5 &

" 0 @

1 5 " % % $ & A " 5 % " 5 # #

$ &

4 1 3 #) " 1

$ " # $ " # %

$ * $ " # " " # # % $ & * $ "" 3 $& 1 3 " $ " # # " & 1 " # " " $ &

September 1999 Issue 1

Methods 4-1

BP Amoco Directional Survey Handbook

BPA-D-004

1 # $ $ $ $ # % " $ % " & ) " $ % " 5 $ # $ & & 1 " $ $ " $ & & 1 ' "

* " 3 # = â&#x20AC;˘ *5 $ " % $ # â&#x20AC;˘ / $ $ â&#x20AC;˘ 1 " $ $ â&#x20AC;˘ # " % $ # $ $ â&#x20AC;˘ $ 3 % # "

1 # $ = â&#x20AC;˘ $ % # $ $ $ % # $ 3 " â&#x20AC;˘ # $ " â&#x20AC;˘ $ # $ " # 8 1 $ % # # " & " & " 5 " # %

4-2 Methods

September 1999 Issue 1

BP Amoco Directional Survey Handbook

BPA-D-004

& 1 # # " $ "" $

" & * " " " & 1 " # " # " # $ # #

" 5 " $& # %

# - 4 / . 1 # #

" % # # " & 0 ' ' "

1 " " $ 5 " 5 &

9 $ &, # 7 ! " " # & Slot in use or planned for use Spare slot

A-2

A-6

Well location at fixed depth (say 500 ft bMSL) Drilled well path Planned well path

A-3

Figure 4.1

A-4

A well planned development

A-1

A-9

A-8

A-5

September 1999 Issue 1

A-7

Methods 4-3

BPA-D-004

BP Amoco Directional Survey Handbook

1 5 " # $ = â&#x20AC;¢ " & ) %

7 !% " & 1 " # 5 $ # â&#x20AC;¢ ) " % $ #

" â&#x20AC;¢ & 1 $ 5 " 5 " $ $ " â&#x20AC;¢ . " $ # # " % $ 5 # â&#x20AC;¢ . " $ % " $ & 1 "

â&#x20AC;¢ . $ " % $ " & $ % # 5 â&#x20AC;¢ # " 8 & 1 $

" # # $ > $ % $ 8 = â&#x20AC;¢ $ > "" $$ & $ # $

# " " $ â&#x20AC;¢ 1 # " "" $ % % # "

4-4 Methods

September 1999 Issue 1

BP Amoco Directional Survey Handbook

BPA-D-004

â&#x20AC;˘ 1 " " â&#x20AC;˘ / 8 # " " # $ " # " % " $ &A # # % # $ " # & slot in use or planned for use spare slot

A-1

A-5

A-4

well location at fixed depth (say 500 ft bMSL) drilled well path planned well path

Figure 4.2 A poorly planned development

A-3

A-2

1 $ $ # % $ # $ 3 " " # & % $

" $ ""& ) " %

" " & # + % "

+ # # " " %

$ * $ % )

" # &

September 1999 Issue 1

Methods 4-5

BP Amoco Directional Survey Handbook

BPA-D-004

It may be necessary to incur extra cost to avoid the paths of wells that have yet to be drilled, or to survey the top-hole sections of wells more accurately than would be needed were the well being drilled in isolation. # " &

" )

3 # ) @

Appendix C contains a Survey Program Data Sheet, useful for inclusion in the drilling program

1 $ " # 3 " 3 $ " $ & " " $ # = â&#x20AC;˘ / "" # # # ! $ 8 â&#x20AC;˘ "" 3 â&#x20AC;˘ 3 > 1 $ " # $ -

# & % " $ & 1 $ $ & ' % $ = ,& 1 & A& % # " & ?& 4 $ " $ $% # & &

B& & -& $ % " & C& $ " " &

4-6 Methods

September 1999 Issue 1

BP Amoco Directional Survey Handbook

BPA-D-004

' $ $ $ F+4 5 # " # $ &

JORPs are covered in Section 5.10

1 " $ $ 7 " 8 % % 8 # !& 9 $ &? # & identify geological objectives

identify drilling objectives

target tolerances while drilling maximum uncertainty of definitive survey

anti-collision, economic target size external magnetic interference relief well contingency regulatory requirements

select survey sequence

check objectives are met

well trajectory, casing program

approved error models

Figure 4.3 Flowchart for survey program design

check program robustness sufficient data redundancy contingency for tool failure

standard running procedures

check operational impact / economics adherence to â&#x20AC;&#x153;lessons learnedâ&#x20AC;? survey equipment suitability for well conditions survey equipment availability impact on drilling process (stationary pipe etc.) best use made of market place minimum cost solution

September 1999 Issue 1

specify program details station intervals minimum depth ranges validation surveys contingency surveys

record in drilling program

Methods 4-7

BP Amoco Directional Survey Handbook

BPA-D-004

$ $ $ -$ " # " $ $ & 1 # 5 " 8 $ $ $ % & 8 $ & * ' 3 &

$ " # " # 3 $ $ # $ & 1 # "" & ' " $ # & 1 " # $ $ # " # " $ $ ; & 9 5 # % " " " 3 " # # "

$ $ = â&#x20AC;˘ ' # " " â&#x20AC;˘ 4 $ # % #

â&#x20AC;˘ " $ 8 % $

4-8 Methods

September 1999 Issue 1

BP Amoco Directional Survey Handbook

BPA-D-004

* .. ,0 , "$ $, ,0 * . + 3 ..

. # " # % $ $ = ,& 1 " " $ # # & # % "" # % # # $ # & ' % # $ " $ & ' " $ #

" $ # " # & ' " $

" $ " " # # " $ # & A& " $ " $ # # 5 5 & 1 #

# & 1

# 3 " " # & ?& 1 " # # 7 ! : " $ $ " " # $ & ' % # $ # $ % # # # $ $ : # # $ $ $ " $ # : # " & 1 5 $ " " % % " " % $ 5 $ $ , " ? &

September 1999 Issue 1

Methods 4-9

BP Amoco Directional Survey Handbook

BPA-D-004

& 1 " " $ # $ " % # "" ; & 1 # # " 5 5 " &

$ " &

Figure 4.4 Schematic of a relief well

Relie

f we ll

last casing shoe above reservoir

Target well

â&#x20AC;&#x153;cone of uncertaintyâ&#x20AC;? around target well

first approach - above last casing shoe

second approach - at kill point

B& 1 " # # # & '" $ # % # $ # #

$ $& '" # # % " 3 " % " # # % % &

4-10 Methods

September 1999 Issue 1

BP Amoco Directional Survey Handbook

BPA-D-004

3 .. "$ $, ,0 * 8( * 1 ,

1 " # $ # 5 " " 3 " # $ & 1 $ " # $

3 #& ) % ) 1 " 8 " & 1 " # 5 # & ,& 9 #

$ ; % $ " $ ? , " A & 1 " = 2Ď&#x192; Absolute Uncertainty = â&#x2C6;&#x161; [ (2Ď&#x192; surface uncertainty)Â˛ + (2Ď&#x192; surface-to-seabed uncertainty)Â˛ +(2Ď&#x192; lateral wellbore uncertainty)Â˛ ] Example: Offshore well in 800m of water. 2Ď&#x192; surface uncertainty = 5m (typical of DGPS) 2Ď&#x192; surface-to-seabed unc. = 8m* 2Ď&#x192; lateral wellbore unc. = 10m 2Ď&#x192; Absolute Uncertainty = â&#x2C6;&#x161;[ 5Â˛ + 8Â˛ + 10Â˛ ] = 13.7m * See Section 3.1 for a discussion of USBL acoustic position uncertainty. Land and hydrographic surveyors will usually quote uncertainties at 2 standard deviations (2Ď&#x192;) by default. Check. In some high step-out development wells, the above criterion may not be practically achievable. A dispensation may be justified on several grounds: â&#x20AC;˘ Knowledge and/or depletion of the reservoir makes a blowout very unlikely â&#x20AC;˘ Wellbore uncertainty is substantially less in the high-side direction that in the lateral direction (this fact could be used by careful planning of the relief well) â&#x20AC;˘ The type of survey data to be acquired is amenable to further processing and accuracy improvement, should it be necessary. IIFR is an example â&#x20AC;˘ There is no practical means of improving the accuracy of the survey program

September 1999 Issue 1

Methods 4-11

BPA-D-004

BP Amoco Directional Survey Handbook

A& ' #

$ ; % $ 3 $ 3 " ; & 1 $ 0) % $ $ $ # $ & Camera-based magnetic surveys are not adequate for this purpose, except over short depth intervals (c. 300m or 1000ft).

?& 9 "" # " " $ % " ; "" # " " 5& 1 " " 3 , & ' "" ; " " # # $ 3 5 & LBL acoustics are described in Section 3.1

There are a number of ways in which limits on the departure from verticality may be determined. Measuring the well inclination in the water column, probably with MWD, is among the simplest. Use of LBL acoustics is probably the most accurate (but also the most expensive).

! 1 '

0 $ $ $ " & ' $ % " = ,& 1 $ $ " & 1 " # $ & 3 "

" $ &C " & A&

$ " " & $ "% $ " " $

$ $ &L &

4-12 Methods

September 1999 Issue 1

BP Amoco Directional Survey Handbook

BPA-D-004

?& *5 " " & $ " $ # # & ' $ " %

"" & 1 $ $ $ ; # " 5 " & * .. ,0 $( $+ & ,0 $

$ % $ " # $ $ " $ % " $ % " 8 $! $ & *5 # $ ; - A " " $ & / $% " " & 5 #

# $ &

$ # $ " "" # 1@ & ' % % $ ; " & * .. ,0 $( $+ &.( * $* & ,0 3 , $3

1 # 8 $ $ $ " "" $ ; " & ' $ % $ 5 " # ? " L " $% " # B " ,B & 9 $ % $ $ $ " " & 5 # $ " % = â&#x20AC;˘ 1 "" # ? " % # â&#x20AC;˘ 1 " #

September 1999 Issue 1

Methods 4-13

BP Amoco Directional Survey Handbook

BPA-D-004

â&#x20AC;˘

$ $ 5 & 1 " 1 0, & , *+ * ,& & ,

1 5 " # 5 $ " " 5 " $% % $ " : "" " # & 1 " $ " $ $ # & 1 # $ " $ $ & 1 " " # " # = ,& " $ " 5 $ # ,%XN $ # " & # 5 " " "" # & A& $ % d % # # % " "" # % S1(di) S2(di),â&#x20AC;ŚSN(di).

?& % d % 4 $ $ $=

ďŁŤ 1 ďŁś 1 1 ďŁˇ S equiv (d i ) = ďŁŹ ... + + + 2ďŁˇ ďŁŹS d 2 S d 2 S N (d i ) ďŁ¸ ďŁ 1( i ) 2( i )

â&#x2C6;&#x2019;

1 2

This formula is based on the simplistic but useful assumptions that (a) the interfering field from each casing string is equal in intensity (b) the intensity decreases with the square of the distance from the casing.

& 3 $ # # &

4-14 Methods

September 1999 Issue 1

BP Amoco Directional Survey Handbook

BPA-D-004

* .. ,0 *$(, +

1 " $ " # $ " $ $ " % "" # & 1 " $ # # " " $ $ $ " & " ( ' '

1 # " $ $ $ =

â&#x20AC;˘ # # â&#x20AC;˘ 1 # " " # 1 " " 1 $ &B & 1 % # $ "" 3 % " " $% 3 % & . % / $ # " # $

& 1 $ $ $ 3 % " $ " 8 " # & * * A ) '

1 3 " # $ # $ $ 3

3 % " " " & # 5 % # "" " "" 3 & . % # $ # " % $ " " 3 " # $ $% " " &

September 1999 Issue 1

Methods 4-15

BP Amoco Directional Survey Handbook

BPA-D-004

1 " $ # " 8 "

$ " $

& 1

& 1 " " 3 F+4

$ $ % "" & 1 # " " 3 $ " " "" & ' % " % # "

% # "

"" " # & ' " $ $ = The precise interpretation of this rule for MWD surveys is described in Section 5.2

4-16 Methods

the amount of corroborative data in the form of check shots, multiple probe runs and the like must be sufficient at every stage to confirm the performance of each instrument run in the hole.

September 1999 Issue 1

BP Amoco Directional Survey Handbook

BPA-D-004

& 9 * )) "

1 " " 4 " % # # 2 5 & 0 $ " $ "

7 1 ! & & -

1 4 " 7 ( 4 !% # # " ( & $ " $ #& 1 4 # # # # " ,LL- % # " " # ! . % " $ # # & 1 "

$ " & & ,0 +*$1 -"2 * &$11 , "*$& (*

$ # ( 4 " # 5 " " = ,& 0 : 0 8 4 ) + ( = K A&BE Ď&#x192;,GĎ&#x192;A G Y & ,B

% ,B Z G Sb + . / = K Ď&#x192;,GĎ&#x192;A G d,G dA G Sb . # = K ? Ď&#x192;,GĎ&#x192;A G H d,G dA G Y & ,

% , Z G Sb

September 1999 Issue 1

Methods 4-17

BP Amoco Directional Survey Handbook

BPA-D-004

# Ď&#x192;, K # &

Ď&#x192;A K ' " $ # , & 1

" " "" # & , K ; # & A K $ + " $ # & Sb K # " & 1 # " % % "" & lesser of : a) 1% of drilled depth b) 10m

most likely position of interfering well

Figure 4.5 The minimum separation rule for major risk wells

3 Ď&#x192; error ellipse

IN IM UM

AL LO W

AB LE

SE PA RA TI O

radius of interfering well radius of planned well

4-18 Methods

3 Ď&#x192; error ellipse

most likely position of planned well

September 1999 Issue 1

BP Amoco Directional Survey Handbook

BPA-D-004

A& 0 : 0 4 ) 1 ( $ $ "

$ % " # & 1 # 4 # " " $ % $ $ 1 4 " # & 0 * A )

$ # " & Specifically, the following personnel must have been assessed by a directional specialist as competent in the following skills: Performing anti-collision calculations

Drafting anti-collision diagrams

Well Planners

Person responsible for â&#x20AC;&#x2DC;signing-offâ&#x20AC;&#x2122; wellsite drawings

Directional Drillers and DD Co-ordinators BPA Person responsible for â&#x20AC;&#x2DC;drill aheadâ&#x20AC;&#x2122; decisions

Using the anti-collision diagram for decision making while drilling

Table 4.1 Required competencies for anti-collision work

) # " % # #

# & $ # # $ &

" # 3 M 4 M4 " $ "" 2 1 6 &

September 1999 Issue 1

Methods 4-19

BP Amoco Directional Survey Handbook

BPA-D-004

" # "

8 & 1 # " " # " # # " 8 & 1 " # " " $ # & &

# " # 8 # " $ " "& For a database to be used for the definitive clearance scan, there must be a process in place which ensures that it is, for practical purposes, identical to the definitive drilling database. It need only contain a subset of the wells in the definitive database, but must at least contain all the wells known to have been drilled in the area of interest.

1 ) ) # &

1 # " # # $ $ $ #& The separations are considered as distances measured perpendicular to the planned well, so that they lie in the plane of the anti-collision diagram. â&#x20AC;&#x2DC;3Dâ&#x20AC;&#x2122; or â&#x20AC;&#x2DC;minimum distanceâ&#x20AC;&#x2122; separations are more conservative, but cannot be adequately represented on the travelling cylinder plot and are therefore not part of the Recommended Practice.

4-20 Methods

September 1999 Issue 1

BP Amoco Directional Survey Handbook

BPA-D-004

&. + & $, $+ 3 ..

* # # " $ 0 8 0 & 1 " # " # $ " " =

A nearby well presents a $ ) if a collision with it would carry a significant risk to personnel or the environment. It presents a ) if the risk to personnel and the environment in the event of a collision would be negligible. The Major/Minor risk classification is preferable to the more prescriptive Flowing/Shut-in classification because it forces the engineer to think through the implications of collision in differing situations. For example, the consequences of collision with an oil-producer just above a shut-in SSSV should certainly be subject to a thorough risk assessment before the well is classified as Minor risk. Conversely, a collision with the same well in the perforated part of the reservoir section might well justify the Minor risk classification. Used in this sense, â&#x20AC;&#x2DC;Minorâ&#x20AC;&#x2122; is a relative term â&#x20AC;&#x201C; a well may be classified as Minor risk without implying that a collision with it would be of minor importance.

) " $ # $ " # % " $ # & A well may present a Major risk for only a part of its length. For example, below the shut-in point, or more than a certain distance above the reservoir. Calculations involving the mud weight, shut-in pressure and fracture gradient may be required to establish at which depth the risk classification changes.

4 " # $ $

"$ $, . (,& * , /

# # $

% " $ &

September 1999 Issue 1

Methods 4-21

BP Amoco Directional Survey Handbook

BPA-D-004

1 # $ " & 1 &B " " # # 21/ 1 & 1 , 1(1 " * $, 9 1 B$* * C 3 ..

1 # " 0 8 # =

K ? Ď&#x192;,GĎ&#x192;A G H ,G A G Sb G & ,

I ,

K ? Ď&#x192;,GĎ&#x192;A G H ,G A G Sb G ,

J ,

# Section A.5 explains how relative surface position uncertainty is included in the minimum separation equation

Ď&#x192;,

K # , &

Ď&#x192;A

K ' " $ # , & 1

" " "" # & K ; # &

, A Sb Section A.5 explains how survey bias is included in the minimum separation equation

K $ + " $ # & K # " &

& # " ) 4 " % $ & Example:

Planned well uncertainty at 1 std. dev. = Ď&#x192;1 = Interfering well uncertainty at 1 std. dev. = Ď&#x192;2 = Hole size in planned well = d1 = 17.5" = Casing OD in interfering well = d2 = 13.375" = Allowance for survey bias = Sb = Drilled depth = DD =

8m 5.5 m 0.445 m 0.340 m 0m 650 m

Separation = 3(8+5.5) + H(0.445+0.340) + 0 + 0.01(650) = 47.4 m

4-22 Methods

September 1999 Issue 1

BP Amoco Directional Survey Handbook

BPA-D-004

1 , 1(1 " * $, 9 1 ,$* * C 3 ..

1 # # " = K

ďŁŤ d + d2 ďŁś 1 Ď&#x192; 2 lnďŁŹ 1 ďŁˇ + (d + d 2 ) + Sb ďŁ RĎ&#x192; 2Ď&#x20AC; ďŁ¸ 2 1

# = Ď&#x192; K

Ď&#x192;12 + Ď&#x192; 22

R K 1 4 Example:

Ď&#x192;1, Ď&#x192;2, d1, d2, Sb as above Tolerable Collision Risk = R = 1 in 80 =

0.0125

Ď&#x192; = â&#x2C6;&#x161; [8Â˛ + 5.5Â˛] = 9.71 m Separation = 9.71â&#x2C6;&#x161; {2 ln [ (0.445+0.340) / [(0.0125)(9.71)(2.51)] ] } +H(0.445+0.340) + 0 = 13.8 m The risk-based separation equation exhibits some unexpected behaviour. In particular, it is meaningless when

d1 + d 2 RĎ&#x192; 2Ď&#x20AC;

< 1

For more on the behaviour of the risk-based separation equation, and its derivation, see A.5.

This occurs when the relative position uncertainty of the planned and interfering wells is so large that the tolerable collision risk cannot be exceeded even if the planned well is drilled straight at the interfering well. The minimum separation In this case can be set to zero and no-go lines need not be drawn.

1 1 4 1 4 # " " 3 " " $ # 2 &

Section 4.4 gives guidance on determining Tolerable Collision Risk

For convenience, a risk level may be used which is less than the value determined from the cost-benefit analysis. Thus, for example, directional software might present a pick-list of rules based on risks of 1/10, 1/20, 1/50, 1/100, 1/200 and 1/500. A calculated TCR of 1/57 would indicate that the 1/100 risk-based rule should be applied.

September 1999 Issue 1

Methods 4-23

BP Amoco Directional Survey Handbook

BPA-D-004

1 , 1(1 " * $, 9 * &C 3 ..

9 # % : " " # # : # $ # & Even when this is done, it is sometimes impractical to apply the standard minimum separations rules immediately below the kick-off point. In this case, good judgement must be used to determine from what depth the standard rules should be enforced.

& )

$ # $ $ # & ' 5 % # $ 3 " %

# > & It is occasionally possible to represent drilling tolerance lines adequately on plan view or vertical section plots, eliminating the need for an anti-collision diagram. For example, where there is no interference near surface, a single interfering well is involved, and the interfering well remains either above, below, or to the left or right of the planned well. Where there is any doubt that the drilling tolerances can be represented accurately, clearly and unequivocally in this way, an anti-collision diagram must be used.

1 $ # " # # . $ ,A V & 1 # # $ # " # # & Use common sense when it is clear that a particular no-go line cannot be violated due to the presence of other, shallower drilling tolerances.

4-24 Methods

September 1999 Issue 1

BP Amoco Directional Survey Handbook

& 3

* $ # $ &

BPA-D-004

$ # $ #

# " 3 " & Where the only deviations from the survey program are altered start and end depths to survey sections, it will usually be sufficient to recalculate the uncertainty in the planned well and to decide if the consequent changes in position uncertainty are significant. Eliminating surveys from the program, changing instrument types, or radically changing depth intervals will always require a full rework of the anti-collision calculations.

# > F + $ 4 $ F+4 B&, & " % " # # $ & ,+* ,0 1 , $+ $. * ,& . ,

) "" # # & ' " $ %

$ # $ % $ # "" ""& When a tolerance line has been crossed, or is likely to be crossed if drilling continues, the situation must be assessed by the onshore drilling team. Firstly, the anti-collision diagram must be examined to confirm whether either the tolerance can be relaxed without violating any no-go areas (for example if the line has been drawn to smoothly join two no-go areas), or

the tolerance line protects only planned well(s) and there is sufficient room to safely re-plan these at a later date.

In either case, an amendment to the anti-collision diagram with the tolerance line moved to allow drilling ahead can be prepared. If only a small section of the diagram is affected, it may be faxed to the rig.

September 1999 Issue 1

Methods 4-25

BP Amoco Directional Survey Handbook

BPA-D-004

It is always better to provide the rig with a revision to the anti-collision diagram than with verbal or written instructions. It will usually only be possible to relax a tolerance line by a limited amount, over a limited extent of the diagram. This information is difficult to convey in words. If the tolerance line protects an existing well, the options to be examined include: •

Plug back and side-track

•

Re-survey with a more accurate tool

•

Perform a QRA analysis to justify drilling ahead

•

4-26 Methods

Drill ahead with increased survey frequency and alertness (this may be appropriate where a tolerance line is just being ‘grazed’)

September 1999 Issue 1

BP Amoco Directional Survey Handbook

4 4

BPA-D-004

& 9 #

For more

1 1 $ 8 "

& 1 8 " % # " "" # & 1 " # $ $ # # "" # = 40â&#x20AC;&#x2122;

20â&#x20AC;&#x2122;

0â&#x20AC;&#x2122;

!" ! # $ %

! &

information on the Travelling Cylinder and its uses, see

40â&#x20AC;&#x2122;

1000â&#x20AC;&#x2122;

2000â&#x20AC;&#x2122;

40â&#x20AC;&#x2122;

20â&#x20AC;&#x2122;

992â&#x20AC;&#x2122;

2910â&#x20AC;&#x2122;

270

1976â&#x20AC;&#x2122;

80â&#x20AC;&#x2122;

992â&#x20AC;&#x2122; 20â&#x20AC;&#x2122;

90 1976â&#x20AC;&#x2122;

4779â&#x20AC;&#x2122; 3826â&#x20AC;&#x2122;

40â&#x20AC;&#x2122;

20â&#x20AC;&#x2122;

60â&#x20AC;&#x2122;

How a nearby offset well appears on a travelling cylinder

40â&#x20AC;&#x2122;

20â&#x20AC;&#x2122;

2910â&#x20AC;&#x2122;

180

3000â&#x20AC;&#x2122;

3826â&#x20AC;&#x2122;

Figure 4.6

20â&#x20AC;&#x2122;

40â&#x20AC;&#x2122;

60â&#x20AC;&#x2122;

80â&#x20AC;&#x2122;

4000â&#x20AC;&#x2122;

4779â&#x20AC;&#x2122;

5000â&#x20AC;&#x2122;

interfering well

planned well

* + * ,& (* /

' $ # 8 & 1

" $ $ $ & " # # 8 &

September 1999 Issue 1

BP Amoco Standard Practice

Methods 4-27

BP Amoco Directional Survey Handbook

BPA-D-004

* + * ,& * & $,

BP Amoco Standard Practice

' $ % # ; # $ & 1 # . " $ %

7 . !& " # # # $ ,A ! & 1 $ " # $ # $

" $ $ % " & 1 " . "

8 # # % # $ # $ "

5 # $ $ # " # & 1 $ " " $ # $ % # # $ " 3 & * .. ,0 &/. , * &$ $* ,

$ " # & 1 " " $ & % " # & 1 % # $ $ & % $ # " # $ # ; & ) # % % $ $ $ " # & $ $ # $ # 1 # # " $ $ & 2 " " # & ' % % " $ # " &

4-28 Methods

September 1999 Issue 1

BP Amoco Directional Survey Handbook

BPA-D-004

320 50 300

40 30

Relative Bearing = 96 deg

Figure 4.7 Radial Distance = 31 m

Travelling cylinder co-ordinates

2347 2370

Relative Depths

Interfering Well

,$ 0$ * , $. * ,& . ,

1 $ " $ $

8 ! $ & "" # % # # # $ " & $ $ # # % % % # $ &

# $ $ "" # $ # 3 " & 9 % # # " 7 $ ! & ' $ % $ $ $ & 1 # &

September 1999 Issue 1

For a step-bystep guide to drawing tolerance lines and completing anticollision diagrams, see ' ( (

) & $ * by Hugh

Williamson, UTG Well Integrity Team

Methods 4-29

BP Amoco Directional Survey Handbook

BPA-D-004

* + ,0 $. * ,& . ,

1 " # $ " $ # " "

$ $ # & Here, there is room to cross the 800 ft line before reaching 1000 ft, whilst staying outside the minimum tolerable separation. Separate tolerance lines have therefore been drawn. 1000 900 800

800

1000 900 800

Figure 4.8 Rules and conventions for drafting tolerance lines

A separate 800 ft tolerance line here would be pointless. It could scarcely be crossed without drilling within the minimum tolerable separation at a greater depth.

1000

960

980

1000

Entering this area would violate the minimum tolerable separation at 990 ft, even though the no-go area has not been plotted

& *

The worksheet, plus 3 completed examples, is in Appendix C.

4-30 Methods

1 1 4 "

# # " # # & ' 5 " "

& # $ " "

# & 1 " "= 1 " 3 " C ) & 1 " $ $ V ) & 1 " M4 $ & . &

September 1999 Issue 1

BP Amoco Directional Survey Handbook

BPA-D-004

" 1 4 % " # % # V/C & # % 2 # 3 % # # " $ 1 4 $ " $ # $% 8 $ & " " A 1 4 "" " # & ) " % " M

F $ # " # " # $ & * 3 "" # 8 " 1 4 % 3 ) & ' $ % " # = â&#x20AC;˘ 1 " " $ # % # 8 % $$ & â&#x20AC;˘ 1 " " @% # " $ % & â&#x20AC;˘ 1 " " $ " 3 " 5 # 1 # $ $ " $ $ % $ % & ' # $ $ & 1 5 5 " # " $ " " 3 & &

September 1999 Issue 1

Methods 4-31

BP Amoco Directional Survey Handbook

BPA-D-004

For more on the practical limitations of QRA applied to anti-collision see

+ , , ! ( & - &.) / & 0 - &

For more information see

+ + &

# 1& $

$ $ - $ $ ! " 2 3

5 ) - $ ) & 1 " # $ " " %

" " M4 # "

& )

# $

$ " " 3 & 3 1 *

)04 3 $ " $ "

" # % # " & ' @ 0 $ ' & " ' % . # U & 1 2 B% EB% ELS B%B,B%L?, B%-BC%EA-& *5 $ " $ #

> & "* ,& ".

$ " #

$ # # & 1 " 0) $ # &

# 0) " $ "" & " # & well being drilled MWD sensors

Figure 4.9 Principle of single wire magnetic ranging

r B

well to be avoided wire inside well carrying current I

eletromagnetic field lines

4-32 Methods

conductor electrically grounded

September 1999 Issue 1

BP Amoco Directional Survey Handbook

BPA-D-004

'" " $ # % $$ $ & 1 " # # & '" % ? , " " "" & 1 " #% " $ # " # $ & " 5 " $ # " # 0)

% #

$ # & "" $ $ $ " # * ! $ " " % $ 8 " % B,

# & 1 " % r% " 0) " $ Âľ I # % ! 6 #% B = 0 2 (r Ă&#x2014; w ) # w 2Ď&#x20AC; r

" $ # & 1 r $ 8 " 3 = r=

Âľ0 I

2Ď&#x20AC; B

( w Ă&#x2014; B) &

"". & $, , " *+$*1 ,&

)04 # # $

# #

& ' "" # " $ # # # " # 8 & # " $ # $ $ " 3 " " $ &

September 1999 Issue 1

Methods 4-33

BP Amoco Directional Survey Handbook

BPA-D-004

1 $ "

% # 5 # " % " 0)

& ) % ,A

" Âą " , " Âą,B " A " 5 % # 5 $ " AB " & ' $ 21/ $ # " &

4 :

1 % $ $ 8 " # " " " # & ' " % " 3 # # " $ & " % # , T $ $ 8 & ) "

' $ " $ &

' $ $ ! &

* " & # $ " 5 $ "

$ & # 3 $ & 1 #

$ $ $ $ & 4 " $ 3 &

4-34 Methods

September 1999 Issue 1

BP Amoco Directional Survey Handbook

BPA-D-004

1 " $ $ $ # # "" "

6 & ' " $ &, # $ $ $ # & /

% , " # $ # " $ &, &

(a)

surveyed well path

(b)

geological target

Figure 4.10 Calculation of the drillerâ&#x20AC;&#x2122;s target

apparent point of penetration

2 s.d. error ellipse

* $ " , # # " $ $ $ $ & ) $ " $ $ $ " LAT& $ $ $ $ $ $ &,, &

September 1999 Issue 1

Methods 4-35

BP Amoco Directional Survey Handbook

BPA-D-004

(c)

geological target

(d)

Figure 4.11 Calculation of the drillerâ&#x20AC;&#x2122;s target (contd.) well direction

inclusion probability drillerâ&#x20AC;&#x2122;s target at 95% confidence

> 95% 90% - 95% < 90%

9 % # " " $ $ $ # # % % LBT% 7 ! $ LBT " !& 1 # &,, % $ & ' & ' .

1 $ $ # 2 $ $ $ ! $ % " $ & ' % " $ $ $ % ! $ " $ " $ LLT % #

$ $ "" & 9 $ $ $ % 5 # % ; $ # % & # % " $ ; " ! $ $ " # $ =

4-36 Methods

5 $ $ $ $ # $ $ &

* &

$ # "

$ &

September 1999 Issue 1

BP Amoco Directional Survey Handbook

BPA-D-004

$ " " $ # $ $ &

" " LBT L T " 3 &

! $ " L T " 5 & ' 5 % " # 3 & '' ' ##

1 ; " ! $ 7 ! #! " $ $ $ & 0 $ " ; " # # % # " $ & 5 % ; $ # ; # & Low angle well

High angle well

(1) uncertainty is magnified by foreshortening

Figure 4.12 highside uncertainty

highside uncertainty

(2) target is truncated at near and far edge by magnified uncertainty

Effect of hole angle on size of drillerâ&#x20AC;&#x2122;s target (side-on view)

geological target drillerâ&#x20AC;&#x2122;s target

# % " $ $ $ " $ $ " $ "" " $ $ & 1 5 % "

" = amount of target truncated at front & back = highside uncertainty / cos (incl)

9 3 # % # $ ! $ LET " &

September 1999 Issue 1

Methods 4-37

BP Amoco Directional Survey Handbook

BPA-D-004

The BP Amoco algorithm and the graphical method are described in Section A.4

& ' 5

0 $ # " # & $ " # " " $ " $ & % ! $ # " $ & 1 $ 3 & ' D 3

" " $ "" # $ $ $ % $ " ; # " ; & 1 " $ $ $ " " & 1 "

% 5 % 1 " # &

! $ " % 8 % " $ ! $ #& exit (or TD) plane

Figure 4.13 Drillerâ&#x20AC;&#x2122;s target volume for a horizontal well

direction of well

entry plane geological target volume drillerâ&#x20AC;&#x2122;s target volume

'" $ $ % "" ! $ 7 !&% # #& 1 $ $ $ $ & ' 8 $ $&

4-38 Methods

September 1999 Issue 1

BP Amoco Directional Survey Handbook

BPA-D-004

Figure 4.14 Pinched-out drillerâ&#x20AC;&#x2122;s target â&#x20AC;&#x201C; a case for geosteering

direction of well

â&#x20AC;&#x153;pinched-outâ&#x20AC;? drillerâ&#x20AC;&#x2122;s target

4 ;

geological target volume

1 5 $ " # " $ # . % * % 1@ % " % % ; & 1 3 " " 5 $

" % # $ % $ $ 5% # $ ' & 1 " % # $ # &

The minimum

' " # & 7 " !% 7 $ $ ! 7 $ ! " % % $ & 1 % 8 # $ " # $ % " # # &

BP Amoco

September 1999 Issue 1

curvature equations are given in Section A.1

Standard Practice

Methods 4-39

BP Amoco Directional Survey Handbook

BPA-D-004

* &

1 " $ $ % ; " #

% & ' % # # 8 " & 2 " % " 3 % & % # $ $ " % &,&

4 <

* '

' " $ ' 4 $ 3 $ # " 8

0) & ' $ & $ % 5 . & " # ' *

' " $ # $ " 0)

$ " % $ ;

# 3 # 0) & 1 # 8

0) ; : $ 5 $ " : $ $ ! $ &

0) " # # # 0) > &

4-40 Methods

September 1999 Issue 1

BP Amoco Directional Survey Handbook

## ' *

' " $ #

BPA-D-004

â&#x20AC;˘ 1 # $ A Â° â&#x20AC;˘ ; A " # $ # ' 4 : # â&#x20AC;˘ 1 $ ; 5 70 5 $ ! # # -

' % 0)

" $ #

$ # $ & ' " $ $ 0) & ' % # & )# &

' " $ 8 $

& ' ! $ 3 $ : " &

$ " # $ # # # " #

0) &

Survey data comparison is described in Section 4.10

It is vital that all IHR corrections are checked for reasonableness as well as numerical accuracy, and that unusually large or highly correlated corrections are investigated by a survey specialist.

September 1999 Issue 1

Methods 4-41

BP Amoco Directional Survey Handbook

BPA-D-004

* "

1 # $ # & ) " $ # $ % " # " # &

in-hole reference interval

Figure 4.15 In-hole referencing â&#x20AC;&#x201C; section drilled with multiple BHAs

gyro multishot survey BHA #3 BHA #1 BHA #2 IHR MWD surveys

BHA #1 BHA #2 BHA #3 MWD surveys

,& # B " ,B , " ? " $ # $ & 1 $ # # 5 " $

" # & ) % # $ A " 3 & 1 0)

" $ # $ # $ &

4-42 Methods

September 1999 Issue 1

BP Amoco Directional Survey Handbook

BPA-D-004

A& $ $ 1 " & 1 3 # $ " $ $ $ " $ $ & AB" , & 1 & ?& + # " # & 1 =

" $ # $ "" " $ " & AB " CB &

A " - $ &

# ; " &BÂ° # &

1 > ' 4 % 70 5 $ ! #& & " % # $ % 0)

# ' 4 & 1# % # " $ # " L Â°% $ ;

& "" ' 4 & 1

& 1 " $ % " 0) 5 " $ & B& ;

# 3 0) > # $ &

September 1999 Issue 1

Methods 4-43

BP Amoco Directional Survey Handbook

BPA-D-004

& .&(. $, $+ * &$** & $, 9 1(. ". -

) $ % ' 4

" $ $ 0) ; # " ; & 1 " # $ 5 =

Table 4.2 Calculation of in-hole reference corrections â&#x20AC;&#x201C; section drilled with multiple BHAs

Measured Depth

Gyro Azimuth

1250 1275 1300 1325 1350

271.62Â° 271.81Â° 271.77Â° 272.04Â° 272.16Â°

1315* 1413 1508 1604 1255* 1699 1793 1300* 1886 1980 2073

MWD Azimuth

BHA #

Interpolated Gyro Azimuth

IHR Correction

Corrected MWD Azimuth

272.7Â° 273.6Â° 274.1Â° 274.3Â° 272.1Â° 274.2Â° 274.7Â° 272.9Â° 276.1Â° 276.2Â° 276.5Â°

1 1 1 1 2 2 2 3 3 3 3

271.93Â°

-0.77Â° -0.77Â° -0.77Â° -0.77Â° -0.44Â° -0.44Â° -0.44Â° -1.13Â° -1.13Â° -1.13Â° -1.13Â°

271.93Â° 272.83Â° 273.33Â° 273.53Â° 271.66Â° 273.76Â° 274.26Â° 271.77Â° 274.97Â° 275.07Â° 275.37Â°

271.66Â°

271.77Â°

* In-hole reference station * *$ " & &$** & $, $+ 13 (* /

' ;

# ' 4 & '" 0) # ' 4 % ;

$ " $

" &

4-44 Methods

September 1999 Issue 1

BP Amoco Directional Survey Handbook

BPA-D-004

1$ + "*$& (* +$* ,0. - & $,

) $ # # $ % 5 ' 4

Figure 4.16 In-hole referencing â&#x20AC;&#x201C; section drilled with single BHA

gyro multishot survey MWD surveys rejected due to external magnetic interference

MWD surveys used for calculating IHR correction

IHR corrected MWD surveys

,& ' " $ A " % ' 4

" 0)

& 1 " # $ 0) 5 " = â&#x20AC;˘ 0) # # " 5 $ " 5 $ â&#x20AC;˘ 0) # " 5 $ ; J &BÂ° # â&#x20AC;˘ 0) # ' 4

# 3 "" $

September 1999 Issue 1

Methods 4-45

BP Amoco Directional Survey Handbook

BPA-D-004

A& 1 " " $ $ 0) % $

& ?& 1

& " % ' 4

" # $ & 1 " # $ # # $ ' 4

Table 4.3 Calculation of in-hole reference corrections â&#x20AC;&#x201C; section drilled with a single BHA

Measured Depth

Gyro Azimuth

6200* 6300 6400 6500 6600 6700 6800

83.23Â° 83.06Â° 82.69Â° 82.24Â° 82.38Â° 81.60Â° 81.45Â°

6276 6370 6467 6562 6655 6749 6842 6936 7030 7125

MWD Azimuth

Interp. Gyro Azimuth

Azimuth Diff.

82.1Â° 81.6Â° 81.3Â° 82.2Â° 81.1Â° 80.7Â°

83.10Â° 82.80Â° 82.39Â° 82.33Â° 81.95Â° 81.53Â°

1.00Â° 1.20Â° 1.09Â° 0.13Â° 0.85Â° 0.83Â° mean

79.9Â° 79.1Â° 77.9Â° 78.0Â°

IHR Correction

Corrected MWD Azimuth

reject â&#x20AC; reject â&#x20AC;Ą +1.03Â° +1.03Â° +1.03Â° +1.03Â° +1.03Â°

80.93Â° 80.13Â° 78.93Â° 79.03Â°

* For illustration only â&#x20AC;&#x201C; reference survey interval should be 25 ft or 10 m. â&#x20AC; Rejected â&#x20AC;&#x201C; statistical outlier. â&#x20AC;Ą Rejected â&#x20AC;&#x201C; azimuth change between reference survey stations >0.5Â° (Azimuth change between 6600 ft and 6700 ft = 81.60Â° â&#x20AC;&#x201C; 82.38Â° = -0.78Â°).

4-46 Methods

September 1999 Issue 1

BP Amoco Directional Survey Handbook

BPA-D-004

1 2 1(1 & ,0 , $. * & $,

' " $ ;

"" $ 0) $ & 1 " $

% " 5 $ " $ $ & 1 5 $ & 1 " # $ "

$ $ $ " 0) " &L " = Max. change in sin(Inclination)sin(magnetic Azimuth) â&#x2030;¤ Âą0.25 Example A proposed IHR section starts at 65Â° inclination, 150Â° magnetic azimuth, and finishes at 75Â° inclination, 130Â° magnetic azimuth. Is this change in hole direction acceptable ? Answer sin(65Â°)sin(150Â°) - sin(75Â°)sin(130Â°) = 0.45 - 0.74 = 0.29 The change in hole direction is too great, and IHR cannot be applied over the whole section. , $. * + * ,& ,0 $+ . & *$, & 1(. $

* " # 0) # $ & ;

" # " % " 5 $ 5 $ " &

September 1999 Issue 1

Methods 4-47

BP Amoco Directional Survey Handbook

BPA-D-004

4 = For a complete discussion of interpolation in-field referencing, see

+ , - )/ & 1 !" $"

00 4 ( 5 * $ ) 6 - $ ! " 2 and ,

00 0 ) 6 - $ - * 7 &" 8 &

Figure 4.17 The IIFR principle

+ * '

$ 3 " " $ & $

$ % 3 " $ $ " $ & . " $ " $ $ " / $ / / $ 0 //0 & # % $ $ " " & 1 " " ""

# $ $ " ?&A & ' % $ # $ " $ " # $ & 1 & 1 3 " " " $ ''94

5 & ''94 "" " $ $ " # $ " $ " & ' "" 7 ! $ % $ $ " $ 3

& Measured Field at Observatory

Mean Offset Derived From Wellsite Survey

Calculated Field at Wellsite

Observatory Wellsite

4-48 Methods

September 1999 Issue 1

BP Amoco Directional Survey Handbook

BPA-D-004

1 + 1

+ % 7 ! " $ " $ 3 :

3 # % $

$ 3 & +"" % % $ " & 1 " $ 3 " $ 5 & 1 $ " " $ " $ # " $ & 1

" $ " " $ & " " % " $ $ $ $ " & 1 $ $ "" & 1 " " " $ " " & 1 # $ =

1 " & 1

" "

" $ &

1 ; " & $ "" " # # " % 5 $ ; " &

1 # $ B B &

September 1999 Issue 1

Methods 4-49

BP Amoco Directional Survey Handbook

BPA-D-004

1 $ # 5 " $ $ " " " $ " # $ & ) 5 % 5 $ " " $ "

& + * ' $#

'94 & ' 3 " $ 3 % $ " 5 # $ ""& 1 $ $ 5 & . $, $+ 1 0, & + . .(

$ " " " " % 3 & 1 $ ''94

0) # $ $ # $ & 1 % " # $ "" = â&#x20AC;˘ 4 $ " # # " $ $ 5 â&#x20AC;˘ '" $ # % " 0) % â&#x20AC;˘ ''94 0) ; # " 0) ; &C

"". & $, $+ +*

% " ''94 3 & 1 $

$ " & 1 # " ''94

# 3 &

4-50 Methods

September 1999 Issue 1

BP Amoco Directional Survey Handbook

BPA-D-004

Real time (rig site)

Figure 4.18

Typical process sequence in an IIFR operation

Regular turn-around (office)

D # $ " "

# # & 9 % "

$ $& 1 " % $ " # # % " 5 # " 8 " & % " " $ $ #

$ 3 $& 0) 3 $ " $ % & * $ # $ & *5 $ $ % $ % G> , "" % 0) > $ $

$ & 9 3 5 5 $ " " $ 5 "

3 &

September 1999 Issue 1

Methods 4-51

BP Amoco Directional Survey Handbook

BPA-D-004

$" $, +$* "*$& ,0

1 " $ " $ # # ''94& 1 $ 3 5 & 1 "" " $ % 5 " $ $ 5 & 1 % # #

= " $ $ % " " " # & 1

" ;

" # & Correction for crustal field declination 1 $ " $ "

$ ; & % # 3 $

& $ " & 1 $ & "" # " " % $ 3 " & OPTION 1

Correction for crustal field declination and drillstring interference

" 5 $ " $ " $ " $ " $ & 1

# " $ $ " # " & + # " # $ " ; # 5 & * " $ " $ $ + , " # & OPTION 2

4-52 Methods

September 1999 Issue 1

BP Amoco Directional Survey Handbook

BPA-D-004

Correction for tool sensor errors, field variation and interference using near real-time data 1 "" "

B&A # " # 5 " $ " " $ " & / $% " % " "" "" # $ & OPTION 3

+* 8( ,&/ $+ . */

1 " 3 " $ 3 # = â&#x20AC;˘ D $ $ " " # â&#x20AC;˘ $ " " # ""

$ â&#x20AC;˘ 0 $

$ " $ % " 3 % " # " " & ' " $ $ % # # $ " # % # 3 " # & '" " $ ''94 " " # % "

$% $ $ & 0 $ $ $ " & 1 # # $ &

September 1999 Issue 1

Methods 4-53

BP Amoco Directional Survey Handbook

BPA-D-004

* & 1 , 0 1 , , &$11(, & $,

3 " ''94 "

$ & 1 % $ % 0) " $ & 4 $ & 1 " " 5 3 5 & Observatory Data (bulk) Geomagnetic Data Centre

Figure 4.19 Typical data flow in an IIFR operation

Observatory Data (real-time)

Permanent Magnetic Observatory

IIFR Processed MWD surveys

Directional Engineerâ&#x20AC;&#x2122;s Office

IIFR Data Processing Office

RAW MWD sensor data

Logging Unit

$3, * " , " , * 0

1 " 7 $ ! # % 8 1 $

2D . * 4 / $ )+LC, ,?& ) $ $ " % / # $ " " & 1 " $ " $ " % $ " $ " $ & '

" " $ " # " 21/&

4-54 Methods

September 1999 Issue 1

BP Amoco Directional Survey Handbook

4 >

BPA-D-004

1 '

0 $ " " $ "

" $ & ' # = â&#x20AC;˘ $ $ 5 " % $ & "

$ " 5 â&#x20AC;˘ 0 $ $ $ 5 " & ' ""

" # 7 !

! '

1 " 5 " $ ' " % "

& - & $*/

0 $ $ $ % # $ & 1 " % B % " " $ % P% ! % z: Bm =

P 4Ď&#x20AC;z 2

Bm 1 K, 1 % z % " ) Âľ) & $ "

Âľ) % , & & " " & ' 5 &

September 1999 Issue 1

Methods 4-55

BP Amoco Directional Survey Handbook

BPA-D-004

1 5 " $ " % % " " "" " & 9 $ &A # # # " # " $ & ' " # & 0 $ % $ # & magnetic sensors

Drill Collar

Mud Motor

Figure 4.20 Estimating magnetic axial interference

P1 Drill Collar

z2 magnetic sensors

Stab.

1 ďŁŤ P1 P2 ďŁś ďŁŹ + ďŁˇ 4Ď&#x20AC; ďŁ z12 z 22 ďŁ¸

Bax =

Mud Motor

Bax =

1 ďŁŤ P1 P2 P3 P4 ďŁś ďŁŹ + + + ďŁˇ 4Ď&#x20AC; ďŁ z12 z 22 z 32 z 42 ďŁ¸

1" & $, - 0,

1 ;

% â&#x2C6;&#x2020;az% 5 $ " 5 " " % % $ " " " $ " & ) " $ " # ; " * ! " % " # $ 5 " 5 = â&#x2C6;&#x2020; az =

180 Bax . .sin( Inc).sin( Azi ) Ď&#x20AC; BH

# BH ; $ " $ ?&A " 5 % Inc Azi $ ; & ' $ % $ " 5 "

$ &BÂ°& 1 # " $ $ , & &

4-56 Methods

September 1999 Issue 1

BP Amoco Directional Survey Handbook

BPA-D-004

2 . , *+ * ,& &$** & $,

$ #

" 5 " " & 1 # " $ &A,= Problem

Solution apparent magnetic north

axial interference vector (magnitude unknown)

B + Bax

(1) we can measure this vector (2) and we know the interference vector acts in this direction (3) and we know the Earthâ&#x20AC;&#x2122;s field vector is this long:

Figure 4.21 B + Bax

Bax

The principle of simple axial interference corrections

B magnetic north (direction relative to drillstring unknown)

(4) so we can work out that magnetic north is in this direction

1 " $ $$ " # $ " = â&#x20AC;˘ 1 # $ " * ! $ " & ) & " " $ " %

# $ â&#x20AC;˘ 1 " 5 " 5 " &L â&#x20AC;˘ . " $ " * ! " " " & 2 " % # "" " 5 " # : # #

; $ #

September 1999 Issue 1

Methods 4-57

BP Amoco Directional Survey Handbook

BPA-D-004

â&#x20AC;˘ " % " # $ # $ = â&#x20AC;˘

$ # & 1 "

& 6 $ " 5 5 $ " Table 4.4 Maximum acceptable axial magnetic interference corrections, by region

Drilling Area

Gulf Coast, Middle East, Far East, Africa, South America, FSU North Sea, Northern Europe, Canada, Norway Alaska

Maximum Acceptable Correction 6Â° 8Â° 10Â°

â&#x20AC;˘ # ,? " " $ $ & ) % 5 " & â&#x20AC;˘ 5 $ "

# " 5 &LB& 1 " # $ " " = Table 4.5 Forbidden hole directions for axial magnetic interference corrections

Azimuth of Well

Forbidden Inclination Range

Magnetic E or W Âą 19Â° or more Magnetic E or W Âą 18Â° Magnetic E or W Âą 15Â° Magnetic E or W Âą 10Â° Magnetic E or W Âą 5Â° or less

no restriction 87Â° â&#x20AC;&#x201C; 93Â° 80Â° â&#x20AC;&#x201C; 100Â° 75Â° â&#x20AC;&#x201C; 105Â° 72Â° â&#x20AC;&#x201C; 108Â°

' $ % "

$ " $ &

4-58 Methods

September 1999 Issue 1

BP Amoco Directional Survey Handbook

1(. $, , ./

8 $ # 0) # $ 5 "

& 1 7 ! 3 0) &

# # " $ & & 1 $ " "" " " $ # " " $ &

BPA-D-004

The development and validation of INTEQâ&#x20AC;&#x2122;s method is described in

00 0 ) # $

$ "*

0 "

$ % $ "

" & 1 " $ 0)

% $ " " $ & 1

" &

4 ? & )# " $ # " $ " 3 $ & 1 : 1 %

% # 4 ' " 4' & * A ) ' & )# 1

M 3 % $ $ " "" # & 7 $ " ! " 7

!& 1 = â&#x20AC;˘ 1 $ # $ " " $ #

September 1999 Issue 1

Methods 4-59

BP Amoco Directional Survey Handbook

BPA-D-004

) $ " "" " % 5 % # " & 1 = â&#x20AC;˘ 1 $ $ " % # # " . " " "

3 % " & "

1 $ # $ " # & 1 "

$ " 5 = 40

Inclination

35 30 25 20

MWD

Gyro

Figure 4.22

A Survey T-Plot

350

500

1000

1500

2000

2500

Azimuth

345 340 335 330 325 320 315

1 # " $ $ " & "" % " & 1 # $ " $ " $ &

4-60 Methods

September 1999 Issue 1

BP Amoco Directional Survey Handbook

BPA-D-004

1 1 & ,Â°> AÂ°> & 9 % 1 EH[ 5 ,,[ " : 5 $ # $ " " 3 & 1 # # $ "" # $ # 5 $ " & 1 3 " # $ & # 1

$ " "

" & *

% " % " # % # #

& ) 3 " ! $ & 9 %

# # & 1 ; % " $ 1@ & 9 $ $ ; # % # $ &

The equations for calculating these ellipses are in Section A.2

9 $ " $ > $ $ = Overlap at 1 s.d.

Good agreement. No further investigation necessary.

Overlap at 1.5 s.d. but not at 1 s.d:

Average agreement. No further investigation necessary.

Table 4.6

Overlap at 2 s.d. but not at 1.5 s.d

Poor agreement. Recheck both surveys carefully.

Rules-of-thumb when using the error ellipse method

No overlap at 2 s.d.

Disagreement. One or other survey almost certainly contains a gross error. Investigate to resolve the discrepancy.

September 1999 Issue 1

Methods 4-61

BP Amoco Directional Survey Handbook

BPA-D-004

2 " % " " $

$ " " % >" " & 1 # 7 3 !& # %

" " # = â&#x20AC;˘ 1 # & $

"" â&#x20AC;˘ 1 #

â&#x20AC;˘ 1 #

) % " # & 1 # # % " $ #

% #

$ & 1 % $ $

& . " ; " & " # " # & Probability that ellipses will not overlap

1 s.d. ellipses

1.5 s.d. ellipses

2 s.d. ellipses

Ratio (R) of ellipse sizes

Table 4.7 Quantitative interpretation of the error ellipse method

37 %

11 %

41 %

13 %

45 %

16 %

R=1

R=2

R=3

4-62 Methods

September 1999 Issue 1

BP Amoco Directional Survey Handbook

BPA-D-004

* ) " ' )

4' " 3 " & ' ; "" # # # "" 5 "

& 1 3 " " # = â&#x20AC;¢ $ â&#x20AC;¢ = â&#x2C6;&#x2014; ' " â&#x2C6;&#x2014; - $ " " â&#x2C6;&#x2014; , & & " " $

â&#x2C6;&#x2014; , & & "" # " 3 " â&#x2C6;&#x2014; "" , & & "" $ â&#x20AC;¢ 9 " "" # â&#x20AC;¢ 4 " ; ""

September 1999 Issue 1

Methods 4-63

BP Amoco Directional Survey Handbook

BPA-D-004

(ft)

Table 4.8 Example of a Relative Instrument Performance analysis for azimuth differences

1349 1444 1538 1632 1727 1822 1916 2011 2106 2200 2294 2388

Comparison survey azimuth survey 1 s.d.

Interpolated reference survey azimuth

Observed azimuth difference

1 std.dev. azimuth difference

Normalise d azimuth difference

survey

1 s.d.

E=A-C

F = â&#x2C6;&#x161; BÂ˛+CÂ˛

(std dev.) G=E/F

135.7Â° 136.4Â° 136.9Â° 137.2Â° 136.9Â° 137.7Â° 138.9Â° 138.1Â° 139.5Â° 141.6Â° 141.6Â° 142.7Â°

0.78Â° 0.78Â° 0.79Â° 0.81Â° 0.82Â° 0.82Â° 0.83Â° 0.84Â° 0.84Â° 0.84Â° 0.85Â° 0.86Â°

136.61Â° 137.54Â° 137.81Â° 138.45Â° 138.59Â° 139.02Â° 139.66Â° 140.45Â° 140.73Â° 141.75Â° 142.18Â° 142.89Â°

0.35Â° 0.35Â° 0.36Â° 0.37Â° 0.37Â° 0.37Â° 0.38Â° 0.38Â° 0.38Â° 0.39Â° 0.40Â° 0.40Â°

-0.91Â° -1.14Â° -0.91Â° -1.25Â° -1.69Â° -1.32Â° -0.76Â° -2.35Â° -1.23Â° -0.15Â° -0.58Â° -0.19Â°

0.85Â° 0.85Â° 0.87Â° 0.89Â° 0.90Â° 0.90Â° 0.91Â° 0.92Â° 0.92Â° 0.93Â° 0.94Â° 0.95Â° mean std. dev.

-1.06 -1.33 -1.05 -1.40 -1.88 -1.47 -0.83 -2.55 -1.33 -0.16 -0.62 -0.20 1.56 s.d. 0.65 s.d.

& $ " $

# $& $ " $ " &

4-64 Methods

September 1999 Issue 1

BP Amoco Directional Survey Handbook

BPA-D-004

1 " # $ % 5 % # = Normalised Difference (Incl. or Azim) Mean Std. Dev.

Interpretation

< Âą 0.5

and

< 0.5

Âą 0.5 to Âą 0.75

0.5 to 1.0

Average agreement

Âą 0.75 to Âą 1.25

1.0 to 1.5

Poor agreement.

Good agreement

Re-check both surveys carefully > 1.25

> 1.5

Disagreement.

Table 4.9 Rules-of-thumb for use with Relative Instrument Performance analyses

One or other survey almost certainly contains a gross error. Investigate to resolve the discrepancy.

September 1999 Issue 1

Methods 4-65/66

BP Amoco Directional Survey Handbook

BPA-D-004

Section 5

Contents

Page

5-1

5-4

5-11

" # $ % &

5-13

' #( %

5-24

)

* + %# &

5-26

5-28

/ % % 0 %

5-29

5-31

3 +4

5-35

Sensor arrangement in Gyrodataâ&#x20AC;&#x2122;s Wellbore Surveyor (large diameter tool)

5-15

5.2

Keeper tool configured for a 9-5/8" or 7" casing survey

5-19

5.3

The RIGS survey probe

5-23

Figure 5.1

September 1999 Issue 1

Survey Tools 5-i

BP Amoco Directional Survey Handbook

BPA-D-004

Section 5

Contents (contâ&#x20AC;&#x2122;d) Table

Page

5.1

Position uncertainty for inclination only surveys

5.2

Quality measures for electronic magnetic multishot surveys (generic)

5-13

5.3

Quality measures common to all Gyrodata surveys

5-17

5.4

Quality measures for Gyrodata gyrocompassing surveys

5-18

5.5

Quality measures for Gyrodata continuous surveys

5-18

5.6

Quality measures for Keeper multishot surveys

5-21

5.7

Quality measures for RIGS surveys

5-24

5.8

JORPs documents currently in use

5-37

5-ii Survey Tools

5-2

September 1999 Issue 1

BP Amoco Directional Survey Handbook

BPA-D-004

The surface and subsurface instrumentation used in wellbore surveying.

Recommended Practices for tool selection and operation are in italics.

! "

September 1999 Issue 1

Survey Tools 5-1

BP Amoco Directional Survey Handbook

BPA-D-004

5--

Their use should be restricted to near-surface sections of isolated exploration wells or well-spaced development wells. # $ "

Table 5.1 Position uncertainty for inclination only surveys

Average Measured Inclination 0Â° 0.5Â° 1Â° 1.5Â° 2Â° 2.5Â° 3Â°

Position Uncertainty at 1.s.d. (ft/1000ft or m/1000m) 13 22 31 39 48 57 65

" % & ' ( ) ) * Inclination only sections near surface should normally be resurveyed later in the drilling operation. " + , -.

5-2 Survey Tools

September 1999 Issue 1

BP Amoco Directional Survey Handbook

BPA-D-004

" " TOTCO " 6 "'7 " + TOTCO

" " "

/TOTCO ) 0# # " 6 "'7 " +

" Teledrift 1 % / ) $ # Anderdrift # 2

" - 3Â° "

4Â°$- 3Â° 5 3Â°$64Â° $

September 1999 Issue 1

Survey Tools 5-3

BP Amoco Directional Survey Handbook

BPA-D-004

5--

" 0# ' # % "

" 0# % 7 â&#x20AC;˘ 8 9 % +92% .

(

â&#x20AC;˘ ( ( ( % 0# " $ -

% $ + . $ + , :. "

5-4 Survey Tools

September 1999 Issue 1

BP Amoco Directional Survey Handbook

BPA-D-004

" ' $ ;$6<-= !

$ + . ' $

! ,$><,= 5 5 +5" 57

" $ 7 ? ? < # % " $ # % + . $ 2

September 1999 Issue 1

Survey Tools 5-5

BP Amoco Directional Survey Handbook

BPA-D-004

% $ 0 0# " + ' "57 " +

# % 2 2 ) ) ( 2 ) " ( " ( -

1 " ! " $ $ 785' 5 0+ "

% 0# + . " " %

+ 3 6. 0# "

5-6 Survey Tools

September 1999 Issue 1

BP Amoco Directional Survey Handbook

BPA-D-004

The determination of this offset is a safety-critical task, and must be checked independently before the BHA is run in hole. % 0#

% " ! 0# & % + >Â° 3Â°. 0# + @4Â° @6;4Â° @-54Â° @:4Â° . " 9+5 : ; ' 40 5 5

% ( ! "

Six-sensor â&#x20AC;&#x2DC;rawâ&#x20AC;&#x2122; data should normally be transmitted to surface, with inclination, azimuth and toolface (and associated QA measures) being calculated from it. < 5 % ; %

All MWD surveys must pass a number of internal and external validation checks. Details are below and in JORPs. " +"57 <057 = 5 0+5"'

" / $ ) % 7 â&#x20AC;˘ A$ â&#x20AC;˘ $

September 1999 Issue 1

Survey Tools 5-7

BP Amoco Directional Survey Handbook

BPA-D-004

â&#x20AC;˘ ! Section A.3 contains details of how to calculate these quantities

" $ %

( B# + , :. > +"57 5 5 ;57 5 "

2( B#

" Each MWD tool must pass a comparison with external data. " 7 CHECK SHOTS

2 0# +, % . ( ! 0#

$ # 7 ( 7

4 3Â°

( ! 7

> 4Â°

C #

5-8 Survey Tools

September 1999 Issue 1

BP Amoco Directional Survey Handbook

BPA-D-004

% < 0# ( !7 ( 7

4 -3Â°

( ! 7

6 3Â°

% # Whenever possible, MWD tools should be changed out during bit trips. "

ELECTRONIC MULTISHOT

( +2 1. % " 0#

$ % 0# 2 1 MULTI-STATION DATA ANALYSIS

% $

+ , 5. $

+ , :. ( 2( $ + . %

September 1999 Issue 1

Survey Tools 5-9

BPA-D-004

BP Amoco Directional Survey Handbook

4 " 5 " 8+ > +"57 ;57 5 "

2( % 7 â&#x20AC;˘ " % 3Â° $ â&#x20AC;˘ " % $ 5&" ' 0+(5"' " + "&

2 % $

1 5

# % # $

+ , 5. $ + , ;. + , :. # ! " 0# 1 ( " ' # + .

5-10 Survey Tools

September 1999 Issue 1

BP Amoco Directional Survey Handbook

BPA-D-004

2 +2 1. " $ + 3 3. 5--

2 1 " % 2 1 % % 2 1 ) 2 1 2 1 6444 1 +211. " %

2 1 6 4= - 4= & "

" $ two probes should be run in tandem for all EMS surveys. 2 1 % 1 + # 1 " .

September 1999 Issue 1

Survey Tools 5-11

BP Amoco Directional Survey Handbook

BPA-D-004

" + /TOTCO ). 0# #

% ) ) " "# 5&" ' 45' "& MWD non-magnetic spacing requirements are in Section 4.9

" $ Non-magnetic spacing requirements for electronic multishots are the same as for MWD, with the additional requirement that neither sensor be within 1.5 m (5 ft) of a tool joint. + 5 " 6

D 2 1 " ;$64 " C

E&C'

+ 3 64.

5-12 Survey Tools

September 1999 Issue 1

BP Amoco Directional Survey Handbook

BPA-D-004

< 5

B# % 2 1 " 7 QA measure

Tolerance

Failure indicates

Possible cause(s) of failure

Divergence between probes â&#x20AC;&#x201C; Lateral

< 5/1000

Systematic azimuth error

magnetic interference

Divergence between probes â&#x20AC;&#x201C; TVD

< 2/1000

Systematic inclination error

tool misalignment or BHA sag

Gravity Field Strength (G-total)

< Âą0.007g* (all surveys)

Inclination and azimuth error

Faulty accelerometer or tool movement

Magnetic Field Strength (B-total)

< Âą700 nT*

azimuth error

magnetic interference, large crustal anomaly

Magnetic Dip Angle

< Âą0.7Â°*

azimuth error

magnetic interference, large crustal anomaly

(all surveys) (all surveys)

Table 5.2 Quality measures for electronic magnetic multishot surveys (generic)

* difference from modelled value

" # $ % &

* / ) " * 2 # ( % $ 2 " ( " * ! 2 ) " * " 7 0 ! 2 C @ â&#x201E;Ś @ 63 4,6 +Latitude. < " $ 2 )

September 1999 Issue 1

Survey Tools 5-13

BP Amoco Directional Survey Handbook

BPA-D-004

& % " # $ &

A ) Wellbore Surveyor +GWS. $

54F 53F " ( " Battery/Memory +RGS-BT. " G +RGS-CT. $ $ 63Â° 5447 '5 "

" Wellbore Surveyor 7 â&#x20AC;˘ 1 â&#x20AC;˘ % " Continuous 7 â&#x20AC;˘ G < â&#x20AC;˘ $ " Battery/Memory ( 7 â&#x20AC;˘ 1 â&#x20AC;˘ + .

5-14 Survey Tools

September 1999 Issue 1

BP Amoco Directional Survey Handbook

BPA-D-004

7 '+ 4 "

" H +-4 . " & - -3= > H= # & 6 53=

accelerometer (non-rotating)

Figure 5.1 Universal joints

exciter/pickoff coils

motor/stator and bearing assembly

torquer coils

Sensor arrangement in Gyrodataâ&#x20AC;&#x2122;s Wellbore Surveyor (large diameter tool)

magnet assembly for torquer coils to force against

gyroscope (rotating)

" -$ ( -$ ( " " ( Wellbore Surveyor Battery/Memory $ + ! . Continuous + 63Â° . !

September 1999 Issue 1

Survey Tools 5-15

BPA-D-004

BP Amoco Directional Survey Handbook

4 +5 "57 <0 "' ? ' " "0 0 07 6 0+; =

% + ( . $ $ 9 64Â°$63Â° "

# 64Â°$63Â° !

" " >4 " C $ 64Â°$63Â° 9 / ) "

5-16 Survey Tools

September 1999 Issue 1

BP Amoco Directional Survey Handbook

BPA-D-004

4 +5 "57 <0 "' ? + 4 0+; =

% Battery/Memory ( + ( $

. " + . " < # B# ( <057 = 5 0+5"'

" 7 QA measure

Tolerance

Failure may indicate

Possible cause(s) of failure

Field roll tests â&#x20AC;&#x201C; mass unbalance (if possible)

< 0.4Â°/hr

poor initial azimuth reference

gyro calibration shift

Field roll tests â&#x20AC;&#x201C; accel. scale factor (if possible)

< 0.00015

systematic inclination error

accelerometer calibration shift

In/Outrun comparison â&#x20AC;&#x201C; inclination

inclination error

depth error or running gear.

In/Outrun comparison â&#x20AC;&#x201C; azimuth

Csg: mn, sd<0.3Â° D/P: mn, sd<0.3Â° Csg: m, sd<0.5Â° D/P: m, sd<0.75Â°

azimuth error

depth error or poor gyro performance

Final zero depth

< 2.0/1000

systematic error, primarily inclination

wireline slippage or stretch â&#x20AC;&#x201C; correct to CCL

Wireline stretch at TD

< 1.5/1000

systematic error, primarily inclination

tool lag on inrun â&#x20AC;&#x201C; correct to CCL

September 1999 Issue 1

Table 5.3 Quality measures common to all Gyrodata surveys

Survey Tools 5-17

BP Amoco Directional Survey Handbook

BPA-D-004

QA measure

Table 5.4 Quality measures for Gyrodata gyrocompassing surveys

Tolerance

Failure may indicate

Possible cause(s) of failure

Single station test – Earth rate

< f1(Inc,Azi)°/hr*

poor initial azimuth reference

noisy data – reinitialise deeper

Single station test – gyro drift & noise

mean<400 bits s.d.<400 bits

poor initial azimuth reference

noisy data – reinitialise deeper

Single station test – accel. drift & noise

mean<50 bits s.d.<50 bits

azimuth error

poor gyro performance or tool movement

I f (Inc,Azi) = 1/{cosInc√[(0.1°sinInc.sinAzi)²+(0.08°)²]} 1

Table 5.5 Quality measures for Gyrodata continuous surveys

QA measure

Tolerance

Initialisation inclination

s.d. Inc < 0.1°

Tool movement or calibration shift during tool make-up

knock during tool make-up

Initialisation azimuth

s.d. Azi < 0.2°

tool movement or calibration shift during tool make-up

knock during tool make-up

Initialisation Earth rate

< f2(Inc,Azi)°/hr*

Tool movement or calibration shift during tool make-up

knock during tool make-up

Drift tune – X gyro

<0.2°, all params <0.2°, all params

invalid survey

poor gyro performance

invalid survey

poor gyro performance

Drift tune – Y gyro

Failure may indicate

Possible cause(s) of failure

I f (Inc,Azi) = 1/{cosInc√[(0.1°sinInc.sinAzi)²+(0.08°)²/6]} 2

5-18 Survey Tools

September 1999 Issue 1

BP Amoco Directional Survey Handbook

BPA-D-004

" Keeper Finder 1 ) $

Cablehead

Zener Sub

5447 '5 "

" J 7

Decentraliser

â&#x20AC;˘ G < â&#x20AC;˘ $ â&#x20AC;˘ 1 % $ $ +

Casing Collar Locator Gamma Sensor 6.35 m / 21 ft

Temperature Sensor

Figure 5.2

Pressure Barrel /Heatshield Keeper Gyro

Keeper tool configured for a 9-5/8 or 7 casing survey

â&#x20AC;˘ 1 $ + ) . "

/ )

Decentraliser

7 '+ 4 "

" J

" 3 +6H . $ 3$64 +6H$>> . $ " & >= $ 6 53=<6 ;3=<- 6-3=

September 1999 Issue 1

Survey Tools 5-19

BPA-D-004

BP Amoco Directional Survey Handbook

" +K L. +K M. " K $ ! -4Â° " L ! -4Â° 4 +5 "57 <0 "' ? 07 6 0+; =

% + (

. + $ .

4Â° >Â°

# - / ) " / ) -4Â° " " / ) 63 63Â° # " + . " (

/ ) % $

5-20 Survey Tools

September 1999 Issue 1

BP Amoco Directional Survey Handbook

BPA-D-004

4 +5 "57 <0 "' ? "&7 6 0+; =

9 " ! * $ +N>Â°. " # $ ) # > , <057 = 5 0+5"'

" 7 QA measure

Tolerance

Field calibration â&#x20AC;&#x201C; mass unbalance

DI < 0.6Â°/hr

Field calibration â&#x20AC;&#x201C; accel. scale factor

Failure may indicate

Possible cause(s) of failure

poor initial azimuth reference

gyro calibration shift

< 0.0033 v/g

systematic inclination error

accelerometer calibration shift

Initialisation â&#x20AC;&#x201C; gyro bias uncertainty

< 0.017Â°/hr

poor initial azimuth reference

noisy data â&#x20AC;&#x201C; reinitialise deeper

Initialisation â&#x20AC;&#x201C; Earth rate horizontal

< 0.07Â°/hr

poor initial azimuth reference

noisy data â&#x20AC;&#x201C; reinitialise deeper

Low angle Mode â&#x20AC;&#x201C; average G bias

< 0.8Â°/hr

azimuth error

poor gyro performance or tool movement

High angle Mode â&#x20AC;&#x201C; average G bias

< 0.15Â°/hr

azimuth error

poor gyro performance or tool movement

Final zero depth

< 1/1000

systematic error, primarily inclination

wireline slippage or stretch â&#x20AC;&#x201C; correct to CCL

Wireline stretch at TD

< 1.5/1000

systematic error, primarily inclination

tool lag on inrun â&#x20AC;&#x201C; correct to CCL

In/Outrun comparison â&#x20AC;&#x201C; inclination

Csg: sd<0.2Â°

inclination error

depth error or running gear.

In/Outrun comparison â&#x20AC;&#x201C; azimuth

Csg: sd<0.5Â°

azimuth error

depth error or poor gyro performance

DS < 1.0Â°/hr

D/P: sd<0.4Â°

D/P: sd<0.75Â°

September 1999 Issue 1

Table 5.6 Quality measures for Keeper multishot surveys

Survey Tools 5-21

BP Amoco Directional Survey Handbook

BPA-D-004

( $ 6 " <

C A1 C $O A 5447 '5 "

! C A1 +H 6= . " $ $ " " 644Â°G # ( + . 634Â°G ( 6 -44FG H + 5= . ( " / $ ) 54Â° ;4Â°

# ! #

GGO $ /C A1P) " C A1 C A1 "

5-22 Survey Tools

September 1999 Issue 1

BP Amoco Directional Survey Handbook

BPA-D-004

7 '+ 4 "

" C A1 & 3 -3= 6;4 +,44 . D 3 ;53= --3 +344 . 1 >:3 +;54 . " D + D. " D " $ ! * 2 "8 $ D 9 * 1 C A1 $ ) $

Cable Head

Roller Centraliser

Pressure Barrel

Figure 5.3 Electronics

The RIGS survey probe

Gyro/ Accelerometers

Roller Centraliser

4 +5 "57 <0 "'

Breech C A1 2 Lock

" " H

6- + .

September 1999 Issue 1

Survey Tools 5-23

BP Amoco Directional Survey Handbook

BPA-D-004

( H,44 < +-6444 < .

" " BG " <057 = 5 0+5"'

* G ) " 7 QA measure Alignment summary

Tolerance < 0.1Â°

Failure indicates

Possible cause(s) of failure

Noisy Alignment

Excessive â&#x20AC;&#x2DC;electricalâ&#x20AC;&#x2122; noise Tool movement.

Table 5.7

Drift checks

< 0.08 ft/min

Tool movement, or invalid survey.

Poor Alignment (1 check) Lost heading.

Quality measures for RIGS surveys

Sensor failure. Tool movement. In/Outrun comparison

within tooldefined ellipses of uncertainty

Out of spec performance at some stage in complete inrun/outrun survey. QC flow chart will indicate whether sufficient QC parameters exist to qualify survey as within specification.

Depth error. Sensor failure. Lost heading.

' #( %

G $ $ / ) % "

5-24 Survey Tools

September 1999 Issue 1

BP Amoco Directional Survey Handbook

BPA-D-004

5--

G $ 7 â&#x20AC;˘ $ â&#x20AC;˘ " ( â&#x20AC;˘ " G $ $ 1 + , -. $ 2

Camera-based magnetic multishots are not a recommended tool type. # ( $ $ -

" 7 â&#x20AC;˘ #

It is strongly recommended that only units ranges between 0-10Â° and 0-24Â° be used.

September 1999 Issue 1

Survey Tools 5-25

BP Amoco Directional Survey Handbook

BPA-D-004

1 O

â&#x20AC;˘ # ! "

â&#x20AC;˘ # " $ $ -

0# " $ 1 % + , :.

< 5

1 O B#

)

* + %# &

1 $

1CA D $ $

5-26 Survey Tools

September 1999 Issue 1

BP Amoco Directional Survey Handbook

BPA-D-004

( " ! 5--

$ $ " $ 0# ( " $ ( $ SRGs must not be used: â&#x20AC;˘ For multishot surveys â&#x20AC;˘ Deeper than 450m/1500ft below rotary table â&#x20AC;˘ In hole inclinations greater than 10Â° " - % -

1 $ 1 +/1CA). 0 *"2B +/1 ). 1 $1 +/1C&). Due to its historically poor performance, use of the Sperry-Sun SRO tool is not recommended. " $ # # D 0&

0# # $ $

September 1999 Issue 1

Survey Tools 5-27

BP Amoco Directional Survey Handbook

BPA-D-004

" "

0+85' + 8 + "' "& 5" + 8 ' ++ ' "

# Surface references must be established and checked by a qualified land surveyor, and recorded with a detailed station description. The survey engineer on the rig must have a copy of this station description. Drift corrections must be computed and applied automatically by software. Reliance on hand computations by the survey engineer is not acceptable.

/ ) 1 ! 5--

" # "

$ %

5-28 Survey Tools

September 1999 Issue 1

BP Amoco Directional Survey Handbook

BPA-D-004

- % -

" 0

" < 5

" 9 7 Make sure a hard copy of the data is provided, with sufficient header data to ensure its traceability. Insist on all data being labelled with the azimuth reference (magnetic, grid or true) and the correction, if any, applied. Visually inspect the survey for spurious data points, often indicated by large dog-leg severities.

/ % % 0 %

' # 2 ' # 1

September 1999 Issue 1

Survey Tools 5-29

BP Amoco Directional Survey Handbook

BPA-D-004

# $

6::4) 1 ( "

- #

# $ + . 1 E&C' ( $ 6 " <

# $ $ / ) $ 1 *

E&C' Engineers should seek advice from programming the Seeker tool in their wells.

UTG

before

" Finder 1 Keeper " Keeperâ&#x20AC;&#x2122;s L$ ( + . 63F " " Finder $ Keeper E&C'

5-30 Survey Tools

September 1999 Issue 1

BP Amoco Directional Survey Handbook

BPA-D-004

" 8 9 2 + *"2B. 6::4 64$><,= & ( 6>$><;= - #

# D ' #( % &

# #

$ +'A 1 'A11. ' "# '

1 Engineers should seek advice from UTG before programming Camera-based gyro tools in their wells.

# $

/ $ )

September 1999 Issue 1

Survey Tools 5-31

BP Amoco Directional Survey Handbook

BPA-D-004

4 - - 5447 '5 "

" 0# " 7 â&#x20AC;˘ % â&#x20AC;˘ 2 $

â&#x20AC;˘ A < â&#x20AC;˘ 4 +5 "

" 0# " / ) 2 ( # (

/ )

% <057 = 5 0+5"'

A Where possible, the MWD engineer should keep his/her own independent depth tally, and seek to resolve any discrepancy with the drillerâ&#x20AC;&#x2122;s tally.

5-32 Survey Tools

September 1999 Issue 1

BP Amoco Directional Survey Handbook

BPA-D-004

- 5447 '5 "

7 â&#x20AC;˘ A + ( FINDS. â&#x20AC;˘ A Battery/Memory 1 G Keeper

$ D 0#

<0 4 " '+ 4 "

2 7 3<6H= +; . 5<6H= +66 . 63<>-= +6- . 9 ; 64 444 3 444 "

" %

" $ "

September 1999 Issue 1

Survey Tools 5-33

BP Amoco Directional Survey Handbook

BPA-D-004

1 " # # -3 644 "

4 +5 "

& ! &

# " / ) " " 6 3<6444 ( " $! <057 = 5 0+5"'

" $! 1 E&C' 4 6Q 4 -Q

5-34 Survey Tools

September 1999 Issue 1

BP Amoco Directional Survey Handbook

BPA-D-004

# +%%&. " D GGO / ) GGO $ GGO

# ' " + . $

2 3 +4 E&C' E & C '

' # " E&C' % E&C' "

' # D"A '

2 E&C'

( " 7 â&#x20AC;˘ 2 â&#x20AC;˘

September 1999 Issue 1

Survey Tools 5-35

BP Amoco Directional Survey Handbook

BPA-D-004

â&#x20AC;˘

â&#x20AC;˘ & ( ) *

D E&C' $ ( % + - /

E&C' C ' & 0

D"A E&C'

$ D E&C' " + .

5-36 Survey Tools

September 1999 Issue 1

JORPs document

Tool Coverage MWD

Anadrill

Anadrill MWD Surveying Procedures Manual*

Baker Hughes INTEQ

JORPs for Directional MWD

JORPs for SSDS Directional MWD*

Surface Readout Gyroscope Operations for BPX Gyrodata

BP JORPs Manual*

Scientific Drilling

BP JORPs*

Northseeking gyro

Surface read-out gyro

Camerabased gyro

EMS

Camerabased magnetic

Teledrift

Anadrill internal procedures document. Adopted as replacement to obsolete MWD JORPs by BP Amoco.

BPX and BHI JORPs Halliburton / Sperry-Sun

Inertial gyro

Remarks

BP Amoco Directional Survey Handbook

September 1999 Issue 1

Service Company

A separate document describes Sperry-Sun’s Interpolation in-field referencing service

Covers the G2 and SRO gyros

Additional and complementary to SORPs, SDC’s internal standard.

Under revision at time of writing

BPA-D-004

Survey Tools 5-37/38

Table 5.8 JORPs documents currently in use

BP Amoco Directional Survey Handbook

BPA-D-004

Section 6

Contents

Page )

6-1

)

+ $ 5

6-2

)

* 4

6-6

) !

6-8

)

6-20

) )

6-22

) ,

4 * + B

6-29

Figure 6.1

Generic failure mode and effects analysis for missed target and well collision

6-4

Generic classification of potential failures in the directional and survey process

6-5

Table 6.1

September 1999 Issue 1

Technical Integrity 6-i/ii

BP Amoco Directional Survey Handbook

BPA-D-004

)

How to minimise the risk of a gross well positioning error and establish an auditable trail from target definition to definitive survey.

% & '

( G 1 "

G 1 <

)

7 â&#x20AC;˘ # â&#x20AC;˘

September 1999 Issue 1

Technical Integrity 6-1

BP Amoco Directional Survey Handbook

BPA-D-004

# 7 â&#x20AC;˘ + . â&#x20AC;˘ + ( / ).

)

+ $ 5

" ( 9 $ 7 6

(

- > % ( " / $ ) 7 â&#x20AC;˘ " / $ ) ( " / ) â&#x20AC;˘

â&#x20AC;˘ " / ) / $ )

6-2 Technical Integrity

September 1999 Issue 1

BP Amoco Directional Survey Handbook

BPA-D-004

8 % % ** 5 8 5

& 9 2 # "

# / ) $ + . 9 H 6 ( 9 2# / ) / ) * ( " $

September 1999 Issue 1

Technical Integrity 6-3

BP Amoco Directional Survey Handbook

BPA-D-004

wrong well plan used for clearance scan

root-cause failure knock-on effect

wrong surface location or elevation used for planning

â&#x20AC;&#x153;on-designâ&#x20AC;? event

wrong input to target tolerance calculations

geological target location or boundary wrongly defined

gross surface location or survey error in drilled well

wrong input data for clearance scan

clearance scan software error inappropriate error model in drilled well

clearance scan results wrong wrong input to a/c tolerance calcs

inappropriate error model in planned well target tolerance calculation error

a/c tolerance calculation error

badly designed error model inappropriate separation rule

target tolerance print or plot error

badly designed separation rule

target tolerance wrong or invalid on plan

a/c tolerance print or plot error a/c tolerance wrong or invalid on plan

rig not at planned location or elevation target tolerance invalidated while drilling

change in target approach direction

anti-collision tolerance invalidated while drilling

survey program not followed target tolerance ignored or misunderstood

a/c tolerance ignored or misunderstood

drilling well plotting error target tolerace violated

statistically extreme survey error

a/c tolerace violated

insufficient or inaccurate projection ahead of bit gross survey error in drilling well

inadequate survey running or quality procedures

survey running or quality procedures mis-applied

tie-in or north reference error

unpredictable survey tool error

Figure 6.1 Generic failure mode and effects analysis for missed target and well collision

6-4 Technical Integrity

September 1999 Issue 1

BP Amoco Directional Survey Handbook

BPA-D-004

' * 4 8

" $ H 6 "

DIRECTIONAL SOFTWARE / STANDARDS 1.

Clearance scan software error

Badly designed error model

Badly designed separation rule

Target tolerance calculation error

Anti-Collision tolerance calculation error

DIRECTIONAL DATABASE 6.

Missing data, surface location or survey error in drilled well

Inappropriate error model in drilled well

PLANNING DATA 8.

Wrong surface location or elevation used for planning

Geological target location or boundary wrongly defined

DIRECTIONAL PLANNING 10. Wrong well plan used for clearance scan 11. Inappropriate error model in planned well 12. Inappropriate separation rule 13. Target tolerance printing/plotting error

Table 6.1 Generic classification of potential failures in the directional and survey process

14. Anti-Collision tolerance printing/plotting error E.

RIG POSITIONING 15. Rig not at planned location or elevation

SURVEY OPERATIONS 16. Survey program not followed 17. Inadequate survey running or quality procedures 18. Survey running or quality procedures mis-applied 19. Unpredictable survey tool error

DIRECTIONAL DRILLING OPERATIONS 20. Change in target approach direction 21. Target tolerance ignored or misunderstood 22. Anti-Collision tolerance ignored or misunderstood 23. Drilling well plotting error 24. Insufficient or inaccurate projection ahead of bit 25. Tie-in or north reference error

September 1999 Issue 1

Technical Integrity 6-5

BP Amoco Directional Survey Handbook

BPA-D-004

)

Section 3.1 describes some of the theory and techniques of surface positioning

* 4

" 0

) " $ " 0

( "

7 %

Appendix C includes an example of a Well Location Memorandum

" %O $

) " 7 â&#x20AC;˘ " + . A <A $ K$ $ $ "

â&#x20AC;˘ " $ G 1 â&#x20AC;˘ 1 < 1 2 2 (

â&#x20AC;˘ 1 < $

G 1 2 % " O " %O

1 D"A 1 B 1 "

6-6 Technical Integrity

September 1999 Issue 1

BP Amoco Directional Survey Handbook

BPA-D-004

< $ G 1 9 % ' $ " D %

Appendix B includes completed examples of a Final Well Position Memo and a final Well Location Data Form

" $ $ 1 + , & + " 9 % '

1 8 % ' # %

* $ $ 1 R D ( $

% " $ # 9

September 1999 Issue 1

Technical Integrity 6-7

BP Amoco Directional Survey Handbook

BPA-D-004

) !

" $

" 7 â&#x20AC;˘ ' â&#x20AC;˘ 1 â&#x20AC;˘ C ) â&#x20AC;˘ % â&#x20AC;˘ % $ & 0# $

" 9 $

$ "

" 9

( $ ! )

6-8 Technical Integrity

September 1999 Issue 1

BP Amoco Directional Survey Handbook

BPA-D-004

' * 8

" 9 )

" 7 â&#x20AC;˘ G O 1 ( # ( G " $ % ' 1 $ # + . & 7 & '57 (3 ' ;

â&#x20AC;˘ % ' D D $ ) % ' + $ . â&#x20AC;˘ D " D $ ( â&#x20AC;˘ '

+ 8 + "' 5 5

â&#x20AC;˘ % O + . â&#x20AC;˘ % ' 1 1 ( # ( G "

&" 5 7 5" " +0' "

â&#x20AC;˘ ' 9 ( D $ )

September 1999 Issue 1

Technical Integrity 6-9

BP Amoco Directional Survey Handbook

BPA-D-004

â&#x20AC;˘ #, + ; 3=(66=. " â&#x20AC;˘ 1 ' 1 1 ( # ( G â&#x20AC;˘ # $G 1 1 ( # ( G 5" #' 77 " 5"57=

â&#x20AC;˘ ' ( 1

â&#x20AC;˘ â&#x20AC;˘ # " G C % + , , G. 6 + &" 5"57=

â&#x20AC;˘ # )

Section 4.2 has details of the relief well drilling contingency requirement

â&#x20AC;˘ '

Section 4.2 has

â&#x20AC;˘ G " % (

details of this calculation

4 " 5 "

â&#x20AC;˘ C ' 1 ( # ( G

6-10 Technical Integrity

September 1999 Issue 1

BP Amoco Directional Survey Handbook

BPA-D-004

' $

" $ $ 7 â&#x20AC;˘ # â&#x20AC;˘ â&#x20AC;˘ 6 &"# 88 50 6 + =

" 1 $ # # + D .

( " 1 $ # ' # )

" 1 $ # '

< 1 $ # 9 6 ; " 80" 5 " 57 8 + ' "57 &" '6 'C "&

9 1 $ # < 7 6 " "

September 1999 Issue 1

Technical Integrity 6-11

BP Amoco Directional Survey Handbook

BPA-D-004

" 7 - " > " , # 3 # H " $ $ 5 " ( % ' $

# $ % ' + . + ( . " 1 $ # < #

Section 6.6 discusses the relationship between directional databases.

4+ 4 +53 ' += 65 6 ' ++ ' 0+85' D 5+& " += 5" 7 '5 "

â&#x20AC;˘ G

7 â&#x2C6;&#x2014; "

+ % O 9 % ' $

6-12 Technical Integrity

September 1999 Issue 1

BP Amoco Directional Survey Handbook

BPA-D-004

â&#x2C6;&#x2014; " â&#x2C6;&#x2014; " +J 2 C"2 . â&#x20AC;˘ G 9 ( 7 â&#x2C6;&#x2014; G % ' â&#x2C6;&#x2014; C

â&#x2C6;&#x2014; G

â&#x20AC;˘ + . % '

$ "8

! +J 2 C"2. â&#x20AC;˘ G + .

+ . 0+; = 4+ &+5 088 ' " " + ' 5+& 5" 6 + & 7 & '57 + <0 + "

â&#x20AC;˘ 9 â&#x20AC;˘ % '

September 1999 Issue 1

Technical Integrity 6-13

BP Amoco Directional Survey Handbook

BPA-D-004

â&#x20AC;˘ C + . 7 â&#x2C6;&#x2014; "

â&#x2C6;&#x2014; " + . â&#x2C6;&#x2014; #

+ ::Q :3Q :4Q D . â&#x20AC;˘ % ' 9 2( 7 â&#x2C6;&#x2014; â&#x2C6;&#x2014; O "8 â&#x2C6;&#x2014; O "8 â&#x2C6;&#x2014; $ + C 8 + 77 "& 5" 0" 0'' 807 + 7 8 77 " Relief well contingency requirements are in Section 4.2

â&#x20AC;˘ G â&#x20AC;˘ G D

6-14 Technical Integrity

September 1999 Issue 1

BP Amoco Directional Survey Handbook

BPA-D-004

5"= &+ ++ + " 5'6 0+; = " +0 " 77 ( '

â&#x20AC;˘ G

" 7 â&#x2C6;&#x2014; & â&#x2C6;&#x2014; G â&#x2C6;&#x2014; D + $ % . 5" 5 <05 8 " ; 0+; = 77 ( ( 5 "

â&#x20AC;˘ G 5 6 + "' 5" #' 77 " " +0' " 77 4+ ; " ; 75 " 8 " 0 77 45+5 " +07

â&#x20AC;˘ G ( 7 â&#x2C6;&#x2014; %

â&#x2C6;&#x2014; # â&#x2C6;&#x2014; % â&#x20AC;˘ G + .

September 1999 Issue 1

Technical Integrity 6-15

BP Amoco Directional Survey Handbook

BPA-D-004

â&#x20AC;¢ G 7 â&#x2C6;&#x2014; % â&#x2C6;&#x2014; % â&#x20AC;¢ C $ "GC + . D 7 â&#x2C6;&#x2014; " â&#x2C6;&#x2014; 9 â&#x20AC;¢ 9 7 â&#x2C6;&#x2014; C â&#x2C6;&#x2014; G

$ + . â&#x20AC;¢ 9 $ 7 â&#x2C6;&#x2014; #

â&#x2C6;&#x2014; G

â&#x2C6;&#x2014; G $

$ 77 " +0' " 5" +5 "& 5+ '7 5+D 5''0+5 5" 088 ' "

â&#x20AC;¢ G " $

6-16 Technical Integrity

September 1999 Issue 1

BP Amoco Directional Survey Handbook

BPA-D-004

â&#x20AC;¢ G ) 7 â&#x2C6;&#x2014; " $ â&#x2C6;&#x2014; " â&#x2C6;&#x2014; " + . â&#x2C6;&#x2014; " " ' 1 + .7 â&#x20AC;¢ + .

$ â&#x20AC;¢ G 7 â&#x2C6;&#x2014; " â&#x2C6;&#x2014; " â&#x2C6;&#x2014; " +" A . â&#x2C6;&#x2014; " + % ' 1 A1 + > -. â&#x2C6;&#x2014; " ! +

. â&#x20AC;¢ 1 1

+ ) .

September 1999 Issue 1

Technical Integrity 6-17

BP Amoco Directional Survey Handbook

BPA-D-004

â&#x20AC;˘ G )

+ . â&#x20AC;˘ G + .

+ . â&#x20AC;˘ G + . ' % # **

' 9 R %

% ' % % ' 1 $ # $ ( 9 ( $ $

% 1 $ # 9 % 7 â&#x20AC;˘ " ' # 1 $ # R â&#x20AC;˘ "

â&#x20AC;˘ " 9

6-18 Technical Integrity

September 1999 Issue 1

BP Amoco Directional Survey Handbook

BPA-D-004

( 0 5--

D 1 $ # D

( # + . 7 â&#x20AC;˘ " $ " % ' 1 â&#x20AC;˘ " â&#x20AC;˘ "

< + .

4 " 5 " 8+ + ' " 4+5' '

8 % & ' ( D

0 0

D$ % 7 â&#x20AC;˘ "

Appendix C contains an example dispensation form

â&#x2C6;&#x2014; C % â&#x2C6;&#x2014; ' < 1 "

9 ( 7

September 1999 Issue 1

Technical Integrity 6-19

BP Amoco Directional Survey Handbook

BPA-D-004

â&#x2C6;&#x2014; 1 ' < 1 "

* â&#x2C6;&#x2014; C " ( â&#x2C6;&#x2014; E #

â&#x2C6;&#x2014; # G â&#x20AC;˘ 2

â&#x20AC;˘ 1 D %

)

G $ $ " ( "

6-20 Technical Integrity

September 1999 Issue 1

BP Amoco Directional Survey Handbook

BPA-D-004

77 50 6 + = 7 5 "

Certain rules (such as not crossing anti-collision tolerance lines and following JORPs) are inflexible. 1 + .

77 0+; = ;57 5 "

" " B#

$ $ 1 $

7 When in doubt, re-survey. 65" 7 "& " "#' "8 + 5"'

# $ ) * $ 7 â&#x20AC;˘ 9 â&#x20AC;˘ 9 â&#x20AC;˘ 1 $ $ â&#x20AC;˘ 8 ( ( $

September 1999 Issue 1

Technical Integrity 6-21

BP Amoco Directional Survey Handbook

BPA-D-004

7 6 * $ Appendix C contains a Non-Conformance Report form suitable for this

> # ) , C 7 . #

)

. 1 $

) )

" ( 1 ( " % 1 9 " 7 â&#x20AC;˘ " + . â&#x20AC;˘ #

6-22 Technical Integrity

September 1999 Issue 1

BP Amoco Directional Survey Handbook

BPA-D-004

â&#x20AC;˘ B B#

â&#x20AC;˘ "

Survey data comparisons are discussed in Section 4.10

+ -

" % "

# " % % $ # % " 7 â&#x20AC;˘ " â&#x20AC;˘ # + .

â&#x20AC;˘ 9 0# â&#x20AC;˘

â&#x20AC;˘ # % 1 B# 1

September 1999 Issue 1

Technical Integrity 6-23

BP Amoco Directional Survey Handbook

BPA-D-004

â&#x20AC;˘

; %

# " ( " / ) 9 ( " $ # ) " unvalidated survey data should never be loaded on the definitive directional database ) "

" + , 64.

9 B#

6-24 Technical Integrity

September 1999 Issue 1

BP Amoco Directional Survey Handbook

77 0+; = <5 6

BPA-D-004

" < "

E&C' " ' # % 1 9 *

" ) " 1

' 7

BP Amoco Standard Practice

6 " - " ( % C ' + $ . ) > 1

, %

# $ "$ + , 64. ( 3 #

H 1 ( ) # (

September 1999 Issue 1

Technical Integrity 6-25

BP Amoco Directional Survey Handbook

BPA-D-004

40(7 6 "& 6 5 5

# $ $ % /

" & ' $ $ + - -. " ' # 5 5 '+ '57 =

" #

G ) 7 â&#x20AC;˘ 1 $ $

â&#x20AC;˘ * (

7 â&#x20AC;˘ â&#x20AC;˘ " â&#x20AC;˘ C < < < â&#x20AC;˘ 1 â&#x20AC;˘ '

6-26 Technical Integrity

September 1999 Issue 1

BP Amoco Directional Survey Handbook

BPA-D-004

9 7 â&#x20AC;˘ â&#x20AC;˘ 8 â&#x20AC;˘ 0# 8 " ; 5 5(5

& (

" " 9 ( 1 1 * #

5'' + + ' "

D 7 â&#x20AC;˘

â&#x20AC;˘

September 1999 Issue 1

Technical Integrity 6-27

BP Amoco Directional Survey Handbook

BPA-D-004

" 65+ #' 4= 5 5 (5'C#04

1 )

+ ' "57 5 5(5 ' 45+ "

' $ ' # " ( ) ' #

" ( # 2#' ' " 7 â&#x20AC;˘ % â&#x20AC;˘ % +

. - â&#x20AC;˘ % +

"8 . 3

6-28 Technical Integrity

September 1999 Issue 1

BP Amoco Directional Survey Handbook

BPA-D-004

1 $ 0 + ; & 75"'

% # ( $ " ( + ( .

) ,

4 * + B

$ $

" 4 +8 + 5"' 5 0+

1 / ) + D . # G %

< 1 ( 7 â&#x20AC;˘ ' â&#x2C6;&#x2014; *

September 1999 Issue 1

Technical Integrity 6-29

BP Amoco Directional Survey Handbook

BPA-D-004

â&#x2C6;&#x2014; " $ â&#x2C6;&#x2014; * $ â&#x20AC;˘ & â&#x2C6;&#x2014; 1 64 444 â&#x2C6;&#x2014; * â&#x2C6;&#x2014; * 0#

â&#x20AC;˘ Calculation of tortuosity is explained in Section A.6

â&#x2C6;&#x2014; % â&#x2C6;&#x2014; " â&#x2C6;&#x2014; ( '6" '57 "; &5 "

& $ $

# 2 # % 1 9 # C" 7 & (5

' # " 7 â&#x20AC;˘ JORPs #

E&C'

6-30 Technical Integrity

September 1999 Issue 1

BP Amoco Directional Survey Handbook

BPA-D-004

â&#x20AC;˘ Approved survey error models "

( â&#x20AC;˘ This Handbook " $ $

1 1 D"A % " 1 E&C'

September 1999 Issue 1

Technical Integrity 6-31/32

BP Amoco Directional Survey Handbook

BPA-D-004

Appendix A

+ * Contents

Page 5

' '

A-1

4 ' %

A-3

A-8

5 !

5 '

A-9

5 #'

A-17

5 )

A-22

Figure A.1

Reverse survey calculation

A-2

A.2

Geometrical construction of the pedal curve

A-7

A.3

The pedal curve and uncertainties in the north and east directions

A-7

A.4

Naming convention for sensor axes

A-8

A.5

A â&#x20AC;&#x2DC;bitâ&#x20AC;&#x2122;s-eye-viewâ&#x20AC;&#x2122; of the target: the basis of the BP Amoco target analysis method

A-10

A.6

Graphical method of target analysis

A-16

A.7

Calculating a no-go area on the travelling cylinder diagram

A-18

September 1999 Issue 1

Mathematical Reference A-i

BP Amoco Directional Survey Handbook

BPA-D-004

Appendix A

+ * Contents (contâ&#x20AC;&#x2122;d)

A.8

Derivation of the risk-based separation rule

A-20

A.9

Behaviour of the risk-based separation rule at low positional uncertainty

A-21

Behaviour of the risk-based separation rule at intermediate positional uncertainty

A-21

Behaviour of the risk-based separation rule at high positional uncertainty

A-22

A.10 A.11

A-ii Mathematical Reference

September 1999 Issue 1

BP Amoco Directional Survey Handbook

BPA-D-004

5-- % A

+ * Some of the equations and formulae underlying the methods described in the main part of the Handbook.

( (

' '

" 7 â&#x2C6;&#x2020;N =

â&#x2C6;&#x2020;MD sin I 1 cos A1 + sin I 2 cos A2 . RF 2

â&#x2C6;&#x2020;E =

â&#x2C6;&#x2020;MD [sin I1 sin A1 + sin I 2 sin A2 ]. RF 2

â&#x2C6;&#x2020;V =

â&#x2C6;&#x2020;MD [cos I1 + cos I 2 ]. RF 2

[

]

C 9

RF =

2 ďŁŤ DL ďŁś tanďŁŹ ďŁˇ ďŁ 2 ďŁ¸ DL

$ DL @ +I I . I I S6 +A A .T

September 1999 Issue 1

Mathematical Reference A-1

BP Amoco Directional Survey Handbook

BPA-D-004

" RF @ 6 DL ( X ( DL ( Y7 RF = 1 +

DL2 DL4 17 DL6 + + 12 120 20160

( X N 4 46Â° Y N 6>Â° 6 64 5 6 8 + + ; + 0+; = '57'075 "

A similar method, 1 also based on interpolating the hole direction, can be found in

World Oil, April 1986

! " u0

u01

u1 u02

r01

r12

u12

r02 Figure A.1

Reverse survey calculation

Îą12

" ' ' ' + . " ' ( 7 r r u1 = 12 u 01 + 01 u12 r02 r02

A-2 Mathematical Reference

September 1999 Issue 1

BP Amoco Directional Survey Handbook

BPA-D-004

' 7 ďŁŤ1 ďŁś u 0 + u1 = 2u 01 cosďŁŹ â&#x2C6; P0 CP1 ďŁˇ = 2u 01 cos(â&#x2C6; P0 P2 P1 ) = 2u 01 (u12 . u 02 ) ďŁ2 ďŁ¸

u 0 = 2u 01 (u12 . u 02 ) â&#x2C6;&#x2019; u1

O '

u 2 = 2u12 (u 01 . u 02 ) â&#x2C6;&#x2019; u1

" + . 9

> â&#x2C6;&#x2020;D12 = r12

Îą12 ďŁŤÎą ďŁś cscďŁŹ 12 ďŁˇ ďŁ 2 ďŁ¸ 2

Îą12

= sin â&#x2C6;&#x2019;1 u1 Ă&#x2014; u 2

4 ' %

' $

>(> (7 ďŁŽ Ď&#x192; n2 ďŁŻ > ( @ Cnev @ ďŁŻĎ&#x192; ne ďŁŻĎ&#x192; ďŁ° nv

Ď&#x192; ne Ď&#x192; nv ďŁš ďŁş Ď&#x192; e2 Ď&#x192; ev ďŁş Ď&#x192; ev Ď&#x192; v2 ďŁşďŁť

A (

September 1999 Issue 1

Mathematical Reference A-3

BP Amoco Directional Survey Handbook

BPA-D-004

* ( #+ * % 5A

" $ ( + . " $ ( + $ T $ $ (7

Ď&#x192; ha ďŁš ďŁş T Ď&#x192; la ďŁş = Thla C nev Thla Ď&#x192; a2 ďŁşďŁť

C hla

ďŁŽ Ď&#x192; h2 ďŁŻ = ďŁŻ Ď&#x192; hl ďŁŻĎ&#x192; ďŁ° ha

Thla

ďŁŽcos I cos A cos I sin A â&#x2C6;&#x2019; sin I ďŁš ďŁŻ ďŁş = ďŁŻ â&#x2C6;&#x2019; sin A cos A 0 ďŁş ďŁŻďŁ° sin I cos A sin I sin A cos I ďŁşďŁť

Ď&#x192; hl Ď&#x192; l2 Ď&#x192; la

# I A ! 6 E 4 0

" ! 7 + . ! $ + . + . + . 0"' + 5 " = 8 5 4 " " 6 77

" > ! " - (7 ďŁŽ Ď&#x192; n2 Cne @ ďŁŻ ďŁŻďŁ°Ď&#x192; ne

A-4 Mathematical Reference

Ď&#x192; ne ďŁš ďŁş Ď&#x192; e2 ďŁşďŁť

September 1999 Issue 1

BP Amoco Directional Survey Handbook

BPA-D-004

0"' + 5 " = 5 5 & ; " ; + '57 4 6

" $ $ > ( (7 C*ne

ďŁŽĎ&#x192; n*2 = ďŁŻ * ďŁŻďŁ°Ď&#x192; ne

* ďŁš Ď&#x192; ne * *T *2 ďŁş = Tne C nev Tne Ď&#x192; e ďŁşďŁť

ďŁŽ1 0 â&#x2C6;&#x2019; tan I cos AďŁš = ďŁŻ ďŁş ďŁ°0 1 â&#x2C6;&#x2019; tan I sin A ďŁť

* Tne

'57'075 " 8 6 + F " 57 ++ + 77 4

" ! 7 1 $ ( @ Ď&#x192; max @

1 $ ( @ Ď&#x192; min @

Ď&#x192; n2 + Ď&#x192; e2 +

(Ď&#x192; n2 â&#x2C6;&#x2019; Ď&#x192; e2 )2 + 4Ď&#x192; ne2 2

Ď&#x192; n2 + Ď&#x192; e2 â&#x2C6;&#x2019;

(Ď&#x192; n2 â&#x2C6;&#x2019; Ď&#x192; e2 )2 + 4Ď&#x192; ne2 2

" ! ( Ď&#x2C6; Ď&#x2C6; 7 tan 2Ď&#x2C6;

2Ď&#x192; ne

Ď&#x192; n2 â&#x2C6;&#x2019; Ď&#x192; e2

$:4Â° P:4Â°

" 7

Ď&#x192; n2 > Ď&#x192; e2

$,3Â° N Ď&#x2C6; maj N P,3Â°

Ď&#x192; n2 < Ď&#x192; e2

$,3Â° N Ď&#x2C6; min N P,3Â°

" ( C*ne (

September 1999 Issue 1

Mathematical Reference A-5

BP Amoco Directional Survey Handbook

BPA-D-004

' * % 7 *

- %

" > , +- . " ( > /G0 1" ) /G0 *8 ) 2( % G $1 7 2 Ď&#x2021; p, Î˝ p 2

Î˝ Ď&#x2021; p, Î˝ $ +Î˝ @-. +Î˝ @>. p.

Example. Find the number of standard deviations at which a 3D error ellipsoid must be drawn to represent a 95% confidence region, assuming the well position errors follow a trivariate normal distribution. Setting p = 0.95 and Î˝ = 3, we find from tables that Ď&#x2021; 02.95,3 = 7.81. The 95% confidence region is therefore represented by a 2.79-sigma error ellipsoid.

4 % ' 98 - :

" ! ! # 7 Ď&#x192;A

[cos A

ďŁŽĎ&#x192; 2 sin A ďŁŻ n ďŁŻďŁ°Ď&#x192; ne

]

Ď&#x192; ne ďŁš ďŁŽcos AďŁš 2 2 2 ďŁşďŁŻ ďŁş = Ď&#x192; n cos A + Ď&#x192; ne sin 2 A + Ď&#x192; e sin A Ď&#x192; e2 ďŁşďŁť ďŁ° sin A ďŁť

" # ( / ) $ 9 # -

A-6 Mathematical Reference

September 1999 Issue 1

BP Amoco Directional Survey Handbook

BPA-D-004

pedal curve

Figure A.2 Geometrical construction of the pedal curve

standard error ellipse

9 # > + .

North standard error ellipse

pedal curve or â&#x20AC;&#x153;footprintâ&#x20AC;?

Figure A.3

Ď&#x192; north

The pedal curve and uncertainties in the north and east directions Ď&#x192; east East

September 1999 Issue 1

Mathematical Reference A-7

BP Amoco Directional Survey Handbook

BPA-D-004

* % + 1 . " 7 X-axis

Gravity Highside

Ď&#x201E;

Figure A.4

Y-axis

Naming convention for sensor axes

Z-axis

Ď&#x201E;

= instrument toolface angle

(down hole)

" Gx, Gy, Gz

Bx, By, Bz + . ! 7 ďŁŤ ďŁś G x2 + G y2 ďŁˇ â&#x2C6;&#x2019; 1 ďŁŹ sin ďŁŹ ďŁˇ ďŁŹ G2 + G2 + G2 ďŁŹ G2 + G2 + G2 ďŁˇ x y z x y z ďŁ¸ ďŁ ďŁ ďŁŤ

Inclination = I = cos â&#x2C6;&#x2019;1 ďŁŹďŁŹ

(

ďŁŤ G B â&#x2C6;&#x2019;G B x y y x

)

ďŁś ďŁˇ ďŁˇ ďŁˇ ďŁ¸

G x2 + G y2 + Gz2 ďŁśďŁˇ ďŁˇ ďŁŹ Bz G x2 + G y2 â&#x2C6;&#x2019; Gz G x B x + G y B y ďŁˇ ďŁ ďŁ¸

Magnetic Azimuth = Am = tan â&#x2C6;&#x2019;1 ďŁŹďŁŹ

ďŁŤ

(

)

(

)

ďŁś

Instrument toolface = Ď&#x201E; = tan â&#x2C6;&#x2019;1 ďŁŹďŁŹ G x ďŁˇďŁˇ ďŁ Gy ďŁ¸

A-8 Mathematical Reference

September 1999 Issue 1

BP Amoco Directional Survey Handbook

BPA-D-004

" 7 G x = â&#x2C6;&#x2019; G sin I sin Ď&#x201E; G y = â&#x2C6;&#x2019; G sin I cosĎ&#x201E;

Gz @ G I B x = B cos Î&#x2DC; cos I cos Am sin Ď&#x201E; â&#x2C6;&#x2019; B sin Î&#x2DC; sin I sin Ď&#x201E; + B cos Î&#x2DC; sin Am cos Ď&#x201E; B y = B cos Î&#x2DC; cos I cos Am cos Ď&#x201E; â&#x2C6;&#x2019; B sin Î&#x2DC; sin I cos Ď&#x201E; â&#x2C6;&#x2019; B cos Î&#x2DC; sin Am sin Ď&#x201E; Bz = B cosÎ&#x2DC;sin I cos Am + B sin Î&#x2DC; cos I

G, B Î&#x2DC;

" 7 Gravity Field Intensity @

G x2 + G y2 + G z2

Magnetic Field Intensity @

B x2 + B y2 + Bz2

Magnetic Dip Angle @ sin â&#x2C6;&#x2019; 1 ďŁŤďŁŹ G x B x + G y B y + Gz Bz ďŁśďŁˇ ďŁ

5 !

G. B

ďŁ¸

5 '

" ) " ' # " !

September 1999 Issue 1

Mathematical Reference A-9

BP Amoco Directional Survey Handbook

BPA-D-004

(4 5 %

A ( + .

Exclusion probability is integrated over the part of each sector lying outside the target... â&#x20AC;Śthen summed over all sectors

Ď&#x2020;i+1

Figure A.5 A â&#x20AC;&#x2DC;bitâ&#x20AC;&#x2122;s-eye-viewâ&#x20AC;&#x2122; of the target: the basis of the BP Amoco target analysis method

Ď&#x2020;i+1â&#x2C6;&#x2019; Ď&#x2020;i Ns

Ď&#x192;l

Ď&#x2020;ij

geological target reference point

Ď&#x2020;i

lij

as-surveyed point of penetration

hij

Vi Ď&#x192;h

Yi standard error ellipse

Xi geological target boundary

1 + ! . Î´

! + ! $ . Îą K$ ( ! ! Îą â&#x2C6;&#x2019; 90Â° M$ ( $

A-10 Mathematical Reference

September 1999 Issue 1

BP Amoco Directional Survey Handbook

BPA-D-004

1 N v $ X i Yi x = ďŁŤďŁŹ X i ďŁśďŁˇ i

ďŁ Yi ďŁ¸

1 $ p = ďŁŤďŁŹ PX ďŁśďŁˇ ďŁ PY ďŁ¸

$ ( + . $

b 9( : # = ; : 8 6 5+& ( 0" 5+=

" (

xi â&#x2C6;&#x2019; p " $ +*28. $

( ďŁŤ sin Îą ďŁŹ Ttp = ďŁŹ â&#x2C6;&#x2019; cosÎą ďŁŹ ďŁ 0

â&#x2C6;&#x2019; cosÎ´ cosÎą ďŁś ďŁˇ â&#x2C6;&#x2019; sin Îą cosÎ´ ďŁˇ ďŁˇ â&#x2C6;&#x2019; sin Î´ ďŁ¸

# ( ( Ttp (x i â&#x2C6;&#x2019; p ) + b

9 ( ďŁŤ cos I cos A cos I sin A â&#x2C6;&#x2019; sin I ďŁś Ttc = ďŁŹ ďŁˇ cos A 0 ďŁ¸ ďŁ â&#x2C6;&#x2019; sin A

( ( $ 7

[

ďŁŤ U i ďŁś ďŁŤ highsideďŁś ďŁŹ ďŁˇ =ďŁŹ ďŁˇ = Ttc Ttp (x i â&#x2C6;&#x2019; p) + b ďŁ Vi ďŁ¸ ďŁ lateral ďŁ¸

September 1999 Issue 1

]

Mathematical Reference A-11

BP Amoco Directional Survey Handbook

BPA-D-004

4 8 8 6 +0 ( 4 "

" ( + . $ ( " ( $ 7 ďŁŤĎ&#x192; 2 C tc = ďŁŹďŁŹ h ďŁ Ď&#x192; hl

Ď&#x192; hl ďŁś T ďŁˇ 2 ďŁˇ = Ttc C nev Ttc Ď&#x192;l ďŁ¸

pdf ( t) =

ďŁŤ 1 ďŁś expďŁŹ â&#x2C6;&#x2019; t T C â&#x2C6;&#x2019; 1tďŁˇ tc ďŁ ďŁ¸ 2 2Ď&#x20AC; det (C tc )

2 2Ď&#x20AC; Ď&#x192; h2Ď&#x192; l2 â&#x2C6;&#x2019; Ď&#x192; hl

ďŁŤ 2 2 ďŁś â&#x2C6;&#x2019; h Ď&#x192; l + 2hlĎ&#x192; hl â&#x2C6;&#x2019; l 2Ď&#x192; h2 ďŁˇ ďŁŹ exp 2 ďŁŹ ďŁˇ 2 Ď&#x192; h2Ď&#x192; l2 â&#x2C6;&#x2019; Ď&#x192; hl ďŁ ďŁ¸

(

)

t = ďŁŤďŁŹ hďŁśďŁˇ ďŁ lďŁ¸

"'70 " 4+ (5( 7 =

" ďŁŤďŁŹ hďŁśďŁˇ â&#x2020;&#x2019; ďŁŤďŁŹ r cos Ď&#x2020; ďŁśďŁˇ ďŁ r sin Ď&#x2020; ďŁ¸

ďŁ lďŁ¸

pdf (r , Ď&#x2020; ) = =

1 2Ď&#x20AC; Ď&#x192; h2Ď&#x192; l2 â&#x2C6;&#x2019; Ď&#x192; hl2

r 2Ď&#x20AC;

Ď&#x192; h2Ď&#x192; l2

â&#x2C6;&#x2019; Ď&#x192; hl2

(

ďŁŤ â&#x2C6;&#x201A; (h, l ) ďŁś exp â&#x2C6;&#x2019; r 2 f (Ď&#x2020; ) det ďŁŹ ďŁˇ ďŁ â&#x2C6;&#x201A; (r , Ď&#x2020; )ďŁ¸

(

)

exp â&#x2C6;&#x2019; r 2 f (Ď&#x2020; )

2 2 2 2 f (Ď&#x2020; ) = Ď&#x192; l cos Ď&#x2020; â&#x2C6;&#x2019; Ď&#x192; hl sin 2Ď&#x2020; + Ď&#x192; h sin Ď&#x2020; 2 2 2

(

2 Ď&#x192; h Ď&#x192; l â&#x2C6;&#x2019; Ď&#x192; hl

A-12 Mathematical Reference

)

September 1999 Issue 1

BP Amoco Directional Survey Handbook

BPA-D-004

N s ( 7 ďŁŤ Ď&#x2020; = Ď&#x2020; + j Ď&#x2020;i +1 â&#x2C6;&#x2019; Ď&#x2020;i i ďŁŹ Ns r =â&#x2C6;&#x17E; ďŁŹ ďŁŹ I ij â&#x2030;&#x2C6; pdf (r , Ď&#x2020; ) dĎ&#x2020; ďŁŹ ďŁŹ Ď&#x2020; â&#x2C6;&#x2019;Ď&#x2020; 2 2 r = hij + lij ďŁŹ Ď&#x2020; = Ď&#x2020; + ( j â&#x2C6;&#x2019; 1) i +1 i i ďŁ Ns

â&#x2C6;Ť

ďŁś ďŁˇ ďŁˇ ďŁˇ dr ďŁˇ ďŁˇ ďŁˇ ďŁ¸

ďŁŤďŁŹ hij ďŁśďŁˇ $ ďŁ lij ďŁ¸

( $ Ď&#x2020; = tan â&#x2C6;&#x2019;1 ďŁŤďŁŹ U i ďŁśďŁˇ i

ďŁ Vi ďŁ¸

( ( $ ( ( $ r =â&#x2C6;&#x17E;

I ij

â&#x2030;&#x2C6;

â&#x2C6;Ť

Ď&#x2020;i + 1 â&#x2C6;&#x2019; Ď&#x2020;i Ns

( )

pdf r , Ď&#x2020;ij dr

r = hij2 + lij2

Ď&#x2020;ij = Ď&#x2020;i + ďŁŤďŁŹ j â&#x2C6;&#x2019; 1 ďŁśďŁˇ Ď&#x2020;i +1 â&#x2C6;&#x2019; Ď&#x2020;i ďŁ

2ďŁ¸

" ( 7 r =â&#x2C6;&#x17E;

I ij

Ď&#x2020;i + 1 â&#x2C6;&#x2019; Ď&#x2020;i 1 N s 2Ď&#x20AC; Ď&#x192; 2Ď&#x192; 2 â&#x2C6;&#x2019; Ď&#x192; 2 h l hl

September 1999 Issue 1

â&#x2C6;Ť

(

( )) dr

r exp â&#x2C6;&#x2019; r 2 f Ď&#x2020;ij

r = h ij2 + lij2

Mathematical Reference A-13

BP Amoco Directional Survey Handbook

BPA-D-004

(

( )) ďŁšďŁş ( ) ďŁşďŁşďŁť r =

ďŁŽ â&#x2C6;&#x2019; exp â&#x2C6;&#x2019; r 2 f Ď&#x2020; ij Ď&#x2020;i + 1 â&#x2C6;&#x2019; Ď&#x2020;i 1 ďŁŻ = 2 ďŁŻ Ns 2 f Ď&#x2020;ij 2Ď&#x20AC; Ď&#x192; h2Ď&#x192; l2 â&#x2C6;&#x2019; Ď&#x192; hl ďŁŻďŁ°

{(

r =â&#x2C6;&#x17E;

hij2 + lij2

) ( )}

2 2 Ď&#x2020;i +1 â&#x2C6;&#x2019; Ď&#x2020;i exp â&#x2C6;&#x2019; hij + lij f Ď&#x2020;ij = Ns 4Ď&#x20AC;f Ď&#x2020;ij Ď&#x192; h2Ď&#x192; l2 â&#x2C6;&#x2019; Ď&#x192; hl2

( )

" hij2 + lij2 ďŁŤďŁŹ hij ďŁśďŁˇ 7 ďŁ lij ďŁ¸

+ .

$ 7

+ .

i 7

1 l

h = l tan Ď&#x2020;ij l â&#x2C6;&#x2019; Vi V â&#x2C6;&#x2019;V = i +1 i h â&#x2C6;&#x2019; U i U i +1 â&#x2C6;&#x2019; U i

lij =

Vi (U i +1 â&#x2C6;&#x2019; U i ) â&#x2C6;&#x2019; U i (Vi +1 â&#x2C6;&#x2019; Vi ) (Ui +1 â&#x2C6;&#x2019; U i ) â&#x2C6;&#x2019; (Vi +1 â&#x2C6;&#x2019; Vi ) tan Ď&#x2020;ij

hij2

+ lij2

lij2

tan

Ď&#x2020;ij + lij2

ďŁŽ Vi (U i +1 â&#x2C6;&#x2019; U i ) â&#x2C6;&#x2019; U i (Vi +1 â&#x2C6;&#x2019; Vi ) ďŁš = = ďŁŻ ďŁş cos2 Ď&#x2020;ij ďŁŻďŁ° (U i +1 â&#x2C6;&#x2019; U i ) cos Ď&#x2020;ij â&#x2C6;&#x2019; (Vi +1 â&#x2C6;&#x2019; Vi ) sin Ď&#x2020;ij ďŁşďŁť lij2

" (

7 Nv Ns

A-14 Mathematical Reference

1â&#x2C6;&#x2019;

â&#x2C6;&#x2018;â&#x2C6;&#x2018; I

()

ij p

i =1 j =1

September 1999 Issue 1

BP Amoco Directional Survey Handbook

BPA-D-004

& - %

" ) ! " ( :;Q + )

:;Q. 9 ( 4

G $

+ bH Ď&#x192; H .

+ bL Ď&#x192; L . 1 ! A 4

* !

(2Ď&#x192; H â&#x2C6;&#x2019; bH ) cos Inc ! A Inc 4 !

! (2Ď&#x192; H + bH ) cos Inc ! AP6;4F 4

! 2Ď&#x192; L â&#x2C6;&#x2019; bL ! AP:4F 4 )

2Ď&#x192; L + bL ! A$:4F

September 1999 Issue 1

Mathematical Reference A-15

BP Amoco Directional Survey Handbook

BPA-D-004

4 ,

" ) 9 # H ( step 6

geol

ogic a

drille

Figure A.6

râ&#x20AC;&#x2122;s ta

2Ď&#x192;L + bL

Graphical method of target analysis

planned well azimuth, A

l targ

2Ď&#x192;H + bH cos Inc

step 3

rget 2Ď&#x192;H - bH cos Inc

2Ď&#x192;L - bL

step 4 step 5

A-16 Mathematical Reference

September 1999 Issue 1

BP Amoco Directional Survey Handbook

BPA-D-004

5 #'

- ' 0+85' 4 " 0"' + 5 " =

7 Ď&#x192;2

2 2 + Ď&#x192; hole Ď&#x192; surf

Ď&#x192; surf

@ C

Ď&#x192; hole

+ . 6

577 5"' 8 + 0+; = ( 5

# ( + . = = + . " ( 7 Sb @ Max U 4 + $ . V

September 1999 Issue 1

Mathematical Reference A-17

BP Amoco Directional Survey Handbook

BPA-D-004

* + $ .

+ . ' * " #& 5

" $ Î˛ + 6- ) . 7 .

> $ 7 ďŁŽcos I cos A cos( Î˛ â&#x2C6;&#x2019; A) â&#x2C6;&#x2019; sin A sin( Î˛ â&#x2C6;&#x2019; A)ďŁš ďŁş ďŁŻ @ ďŁŻcos I sin A cos( Î˛ â&#x2C6;&#x2019; A) + cos A sin( Î˛ â&#x2C6;&#x2019; A)ďŁş ďŁş ďŁŻ â&#x2C6;&#x2019; sin I cos( Î˛ â&#x2C6;&#x2019; A) ďŁť ďŁ°

7 I @

A @ #! "G 0

interfering well

Figure A.7 Calculating a no-go area on the travelling cylinder diagram

Î˛

minimum allowable separation no-go area

A-18 Mathematical Reference

September 1999 Issue 1

BP Amoco Directional Survey Handbook

BPA-D-004

Ď&#x192; 2 @

Ď&#x192; 1 @ uT C1u

2 uT C2 u + Ď&#x192; surf

7 C1

@ ' (

(

Ď&#x192; surf @ C 6 .

+ , >.

+ $#( % - +

" $ S

ďŁŤ d 1 + d 2 ďŁś d1 + d 2 = Ď&#x192; 2 lnďŁŹ ďŁˇ + ďŁ PĎ&#x192; 2Ď&#x20AC; ďŁ¸ 2

" G 9 # ; O S $ $ Ď&#x192; R +

. %

z 7 ďŁą (z â&#x2C6;&#x2019; S)2 ďŁź 1 exp ďŁ˛â&#x2C6;&#x2019; f ( z) = ďŁ˝ 2Ď&#x192; 2 ďŁž Ď&#x192; 2Ď&#x20AC; ďŁł

September 1999 Issue 1

Mathematical Reference A-19

BP Amoco Directional Survey Handbook

BPA-D-004

# d1 + d 2 2

â&#x2C6;Ť f (z)dz

P = â&#x2C6;&#x2019;

d1 + d 2 2

+ # ;. % ( + $ . 1 ďŁŤ d1 + d 2 ďŁś P â&#x2030;&#x2C6; (d1 + d 2 ) f ďŁŹ ďŁˇ ďŁ 2 ďŁ¸

[

]

2ďŁź ďŁą ďŁ´ S â&#x2C6;&#x2019; (d1 + d 2 ) / 2 ďŁ´ exp ďŁ˛â&#x2C6;&#x2019; ďŁ˝ Ď&#x192; 2Ď&#x20AC; 2Ď&#x192; 2 ďŁ´ ďŁ´ ďŁž ďŁł

d1 + d 2

S (

Figure A.8

planned well

interfering well

Derivation of the risk-based separation rule

Ď&#x192; f(z)

z=0 d + d2 z= _ 1 2

z=S z=

d1 + d 2 2

" ( # (

A-20 Mathematical Reference

September 1999 Issue 1

BP Amoco Directional Survey Handbook

BPA-D-004

% + 6. Actual Collision Risk Collision Risk (low position uncertainty)

Case 1

Ď&#x192; <

d +d 0.242

Figure A.9

Collision Risk (higher position uncertainty)

P Tolerable Collision Risk

Ď&#x192;b Ď&#x192;a

Sa S b

Behaviour of the risk-based separation rule at low positional uncertainty

Minimum Separation increases as Combined Position Uncertainty increases

# + -. " Case 2 d +d 0.399

> Ď&#x192; > 0.242

d +d 1

Figure A.10

Behaviour of the risk-based separation rule at intermediate positional uncertainty

Tolerable Collision Risk

Ď&#x192;b Ď&#x192;a S b Sa

Minimum Separation decreases as Combined Position Uncertainty increases

2 ( + >.

September 1999 Issue 1

Mathematical Reference A-21

BP Amoco Directional Survey Handbook

BPA-D-004

Case 3

Ď&#x192; > 0.399

d +d

Figure A.11 Behaviour of the risk-based separation rule at high positional uncertainty

Tolerable Collision Risk Tolerable Collision Risk is never exceeded - no Minimum Separation exists

Ď&#x192;b Ď&#x192;a

5 )

" D"A the average excess dogleg severity over plan #

DTD + D0 . " ! 7

i P

I Pi

APi

]

0â&#x2030;¤i â&#x2030;¤ M

j S

A-22 Mathematical Reference

I Sj

ASj

]

0â&#x2030;¤ j â&#x2030;¤ N

September 1999 Issue 1

BP Amoco Directional Survey Handbook

BPA-D-004

9 + # 6. 7

{

]}

[

DLiP = cos â&#x2C6;&#x2019;1 cos( I Pi â&#x2C6;&#x2019; I Piâ&#x2C6;&#x2019;1 ) â&#x2C6;&#x2019; sin I Piâ&#x2C6;&#x2019;1 sin I Pi 1 â&#x2C6;&#x2019; cos( A Pi â&#x2C6;&#x2019; A Piâ&#x2C6;&#x2019;1 )

7 1 DLS P = DTD â&#x2C6;&#x2019; D0

â&#x2C6;&#x2018; DL i =1

i P

O $ 7 1 DLS S = DTD â&#x2C6;&#x2019; D0

{

â&#x2C6;&#x2018; DL j =1

j S

]}

[

DLSj = cos â&#x2C6;&#x2019;1 cos( I Sj â&#x2C6;&#x2019; I Sj â&#x2C6;&#x2019;1 ) â&#x2C6;&#x2019; sin I Sj â&#x2C6;&#x2019;1 sin I Sj 1 â&#x2C6;&#x2019; cos( ASj â&#x2C6;&#x2019; ASj â&#x2C6;&#x2019;1 )

" 7 Wellbore Tortuosity =

September 1999 Issue 1

DLS S â&#x2C6;&#x2019; DLS P

Mathematical Reference A-23/24

BP Amoco Directional Survey Handbook

BPA-D-004

Appendix B

Contents

Page

" # $ %

$ '

(

)

! & * (

September 1999 Issue 1

Approved Tool Error Models B-i/ii

BP Amoco Directional Survey Handbook

BPA-D-004

An inventory of the survey tool error models approved for use in BP Amoco.

! "

" # $ % & â&#x20AC;˘ ' ( â&#x20AC;˘ ( ) # â&#x20AC;˘ ( The standard ) * format for survey error models # tool is described in +

September 1999 Issue 1

Approved Tool Error Models B-1

BPA-D-004

B-2 Approved Tool Error Models

MWD - Standard

MWD

MWD with no (or no known) special corrections

The model allows for the fact that axial interference may marginally exceed the upper limit specified in Section 4.9 when the well is near to horizontal east/west

MWD + Sag correction

MWD+SAG

MWD+SG

MWD with a BHA deformation correction applied

Covers all BHA corrections, from simple 2D to finite-element 3D models

MWD + Short Collar correction

MWD+SCC

MWD+SC

MWD with single station axial interference correction applied ( 4.9)

â&#x20AC;&#x153;Short Collarâ&#x20AC;? is the name of Sperry-Sunâ&#x20AC;&#x2122;s correction, but the error model covers all such

MWD + Sag + SC corrections

MWD+SAG+SC

MWD+SS

MWD with both BHA sag correction and single station axial interference correction applied

MWD + IHR correction

MWD+IHR

MWDIHR

In-hole referenced MWD (

MWD + IFR correction

MWD+IFR

MWDIFR

September 1999 Issue 1

with time-varying field applied. Model is applicable whether or not Short Collar type correction is applied.

Table B.1

Approved Survey Tool Error Models â&#x20AC;&#x201C; MWD (Part 1 of 2)

Assumes a BHA sag correction is applied to enhance inclination accuracy Assumes a BHA sag correction is applied to enhance inclination accuracy.

BP Amoco Directional Survey Handbook

4.8). In-field referenced MWD ( 4.7),

MWD + IFR [Alaska]

MWD+IFR:AK

MWDIAK

In-field referenced MWD in Alaska

Model takes account of increased violence of magnetic field disturbances in Alaska. Assumes a BHA sag correction is applied to enhance inclination accuracy

MWD + IFR [Wytch Farm]

MWD+IFR:WF

MWDIWF

In-field referenced MWD at Wytch Farm

Model takes account of observed low levels of axial low level interference using Anadrill BHA components and design. Assumes a sag correction is applied to enhance inclination accuracy

MWD + IFR + Multi-station

MWD+IFR+MS

MWDIMS

In-field referenced MWD with multistation analysis and correction ( 4.9) applied in post-processing

Assumes a BHA sag correction is applied to enhance inclination accuracy

MWD+crust

MWD+CA

MWD where local magnetic field has been measured (or derived from aero-magnetic data) and corrected for, but short-term time variations are not applied.

Assumes a BHA sag correction is applied to enhance inclination accuracy

MWD + Crustal + SC corrections

MWD+CA+SC

MWD+CS

Same as MWD + Crustal Anomaly correction but with single station axial interference correction applied

Assumes a BHA sag correction is applied to enhance inclination accuracy

Table B.1

Approved Survey Tool Error Models â&#x20AC;&#x201C; MWD (Part 2 of 2)

BPA-D-004

Approved Tool Error Models B-3

MWD + Crustal Anomaly corrn

BP Amoco Directional Survey Handbook

September 1999 Issue 1

BPA-D-004

B-4 Approved Tool Error Models

EMS - Standard

EMS

Electronic multishot with no (or no known) special corrections

Includes ex-BP â&#x20AC;&#x153;Electronic Single Shotsâ&#x20AC;? model. Assumes large axial interference errors have been corrected.

EMS + Sag correction

EMS+SAG

EMS+SG

Electronic multishot with a BHA deformation correction applied

Covers all BHA corrections, from simple 2D to finite-element 3D models. Assumes large axial interference errors have been corrected.

EMS + IHR correction

EMS+IHR

EMSIHR

In-hole referenced electronic multishot ( 4.8).

Assumes a BHA sag correction is applied to enhance inclination accuracy.

EMS + IFR correction

EMS+IFR

EMSIFR

In-field referenced electronic multishot ( 4.7), with time-varying

Assumes a BHA sag correction is applied to enhance inclination accuracy.

field applied. Model is applicable whether or not Short Collar type correction is applied. EMS+IFR:AK

EMSIAK

In-field referenced electronic in Alaska

Model takes account of increased violence of magnetic field disturbances in Alaska. Assumes a BHA sag correction is applied to enhance inclination accuracy

EMS + Crustal Anomaly corrn

EMS+crust

EMS+CA

Electronic multishot where local magnetic field has been measured (or derived from aero-magnetic data) and corrected for, but short-term time variations are not applied.

Assumes large axial interference errors have been corrected.

Table B.2

Approved Survey Tool Error Models - Electronic Magnetic Multishots

BP Amoco Directional Survey Handbook

September 1999 Issue 1

EMS + IFR [Alaska]

RIGS

INTEQ RIGS multishot surveys

BHI Seeker multishot

Seeker MS

SKR MS

All INTEQ Seeker ( surveys

Ferranti FINDS multishot

FINDS

Gyrodata - gyrocompassing m/s

GYD GC MS

GYD GC

Older Gyrodata gyro multishots, plus all battery/memory tool surveys (RGS-BT)

Gyrodata - cont. casing m/s

GYD CT CMS

GYD CC

Gyrodata multishot surveys with continuous tool (RGS-CT) in casing. OD 13-3/8â&#x20AC;? or less.

Gyrodata - cont. drillpipe m/s

GYD CT DMS

GYD CD

Gyrodata pump-down multishot surveys with continuous tool (RGSCT) in drill-pipe.

Gyrodata - large ID casing m/s

GYD LID MS

GYD LC

Gyrodata multishot surveys (gyrocompassing or continuous tool) in larger size casing strings (greater than 13-3/8â&#x20AC;? OD).

Gyrodata â&#x20AC;&#x201C; bat/mem drop m/s

GYD BM MS

GYD BM

Gyrodata multishot using Battery/Memory tool in any configuration.

Table B.3

5.8) multishot All Ferranti FINDS ( 5.8) surveys Replaces ex-BP â&#x20AC;&#x153;Gyrodata multishot into open holeâ&#x20AC;? model.

Includes an increased misalignment term

Approved Survey Tool Error Models - North Seeking and Inertial Gyro Multishots (Part 1 of 2)

BPA-D-004

Approved Tool Error Models B-5

BHI RIGS multishot

BP Amoco Directional Survey Handbook

September 1999 Issue 1

BPA-D-004

B-6 Approved Tool Error Models

5.8)

Schlumberger GCT multishot

GCT MS

GCT

GCT surveys in casing or open hole.

GCT = â&#x20AC;&#x153;Gyro Continuous Toolâ&#x20AC;? (

SDC Finder - multishot

Finder MS

FDR MS

Finder multishots in casing or drill pipe

Replaces ex-BP â&#x20AC;&#x153;Inrunâ&#x20AC;? and â&#x20AC;&#x153;Outrunâ&#x20AC;? models

SDC Keeper - casing m/s

KPR csg MS

KPR CM

Keeper multishot surveys in casing. OD 13-3/8â&#x20AC;? or less.

SDC Keeper - drillpipe m/s

KPR d/p MS

KPR DP

Keeper pump-down multishot surveys in drill-pipe.

SDC Keeper - large ID csg m/s

KPR LID MS

KPR LC

Keeper multishot surveys in larger size casing strings (greater than 13-3/8â&#x20AC;? OD).

Includes an increased misalignment term

Sperry-Sun G2 multishot

G2 gyro MS

G2 MS

G2 ( 5.8) multishots in casing, drill pipe or open hole

Replaces ex-BP â&#x20AC;&#x153;Staticâ&#x20AC;? and â&#x20AC;&#x153;Dynamicâ&#x20AC;? models

Approved Survey Tool Error Models - North Seeking and Inertial Gyro Multishots (Part 2 of 2)

September 1999 Issue 1

BP Amoco Directional Survey Handbook

Table B.3

Inclinometer (Totco/Teledrift)

INC

Inclination only surveys in nearvertical hole, including TOTCO, Teledrift and Anderdrift.

Inclinometer + known azi trend

INC+trend

INC+TR

Inclination only surveys in nearvertical hole, where formation dip and experience enables direction of drift to be predicted.

Table B.4

BP Amoco Directional Survey Handbook

September 1999 Issue 1

Replaces ex-BP â&#x20AC;&#x153;Inclinometer (azimuth in known quadrant)â&#x20AC;? model

Approved Survey Tool Error Models - Inclination Only Surveys

BPA-D-004

Approved Tool Error Models B-7

BPA-D-004

B-8 Approved Tool Error Models

Camera-based mag single shot

CB mag SS

CBM SS

Traditional (mechanical) magnetic single shot ( 5.5)

Conventional SRG single shots

SRG

Optically-referenced gyro single shots ( 5.6) Includes SDC Keeper when used in â&#x20AC;&#x153;siteline reference modeâ&#x20AC;?.

Tool types include SRG and MSRG (scientific Drilling), Sigma (INTEQ) and SRO (Sperry-Sun).

Camera-based gyro single shots

CB gyro SS

CBG SS

Traditional surface referenced gyro tool run on wireline, including â&#x20AC;&#x153;level rotorâ&#x20AC;? gyros and Sperry-Sun SU3.

Replaces ex-BP â&#x20AC;&#x153;PGSSâ&#x20AC;? model.

Gyrodata - gyro single shots

GYD SS

Gyrodata gyro orientation surveys

SDC Keeper - gyro single shots

KPR SS

Keeper gyro orientation surveys

SDC Keeper â&#x20AC;&#x201C; surface ref s/s

KPR SR SS

KPR SR

Keeper gyro orientation surveys, where azimuth alignment is achieved by optical referencing at surface.

SDC Finder - gyro single shots

Finder SS

FDR SS

Finder gyro orientation surveys

NS Gyro single shots

NS gyro SS

NSG SS

North seeking gyro orientation surveys taken with unspecified tool.

Approved Survey Tool Error Models - Other Single Shot Types

Excludes siteline (ie. surface) referenced surveys

Note Gyrodata, SDC Keeper and SDC Finder have their own models, which should be used if the tool type is known to be one of these.

BP Amoco Directional Survey Handbook

September 1999 Issue 1

Table B.5

Assumes tandem probes are run and that both are adequately magnetically spaced. Replaces ex-BP â&#x20AC;&#x153;PMSSâ&#x20AC;?.

CBG MS

Traditional optically referenced gyro surveys run on wireline, including â&#x20AC;&#x153;level rotorâ&#x20AC;? gyros and Sperry-Sun SU3 ( 5.8).

BP Amoco Directional Survey Handbook

September 1999 Issue 1 CB gyro MS

Camera-based gyro multishot

Replaces ex-BP â&#x20AC;&#x153;PGMSâ&#x20AC;? model.

CB mag MS

CBM MS

Traditional (mechanical) magnetic multishot ( 5.5)

Dipmeter or other wireline log

Dipmeter

DIPMTR

Wireline conveyed logging tools with directional survey capability ( 5.7).

Sperry-Sun BOSS gyro multishot

BOSS gyro

BOSS

Sperry-Sun BOSS multishot surveys ( 5.8).

Table B.6

Assumes adequate magnetic spacing. Replaces ex-BP â&#x20AC;&#x153;PMMSâ&#x20AC;?. Schlumberger OBDT, BGT are examples

Approved Survey Tool Error Models - Other Multishot Types

BPA-D-004

Approved Tool Error Models B-9

Camera-based magnetic multishot

BPA-D-004

B-10 Approved Tool Error Models

Blind drilling

Blind

n/a

Hole intervals where no surveys are taken

Model assumes well direction deviates from last known survey at a constant rate. Errors grow with square of distance drilled.

Unknown survey

Unknown

n/a

Any survey data of unknown or dubious type

Replaces ex-BP â&#x20AC;&#x153;unknown multishotâ&#x20AC;? model.

Zero Error model

Zero Error

n/a

Used to set position uncertainty to zero down to a given depth (eg. sidetrack point).

Table B.7

Approved Survey Tool Error Models - Special Models

BP Amoco Directional Survey Handbook

September 1999 Issue 1

BP Amoco Directional Survey Handbook

BPA-D-004

Appendix C

Contents

Page

C-5

C-8

C-9

C-10

C-12

C-14

C-16

C-18

" #" !

C-20

$ % !

C-22

& % ! '

C-27

September 1999 Issue 1

Data and Work Sheets C-i/ii

BP Amoco Directional Survey Handbook

BPA-D-004

(

Checklists and proformas to facilitate auditability and quality assurance.

! ! "#$ % & # '(&' )* & +% , + ,

# )*

! ' ) "

September 1999 Issue 1

Data and Work Sheets C-1

BP Amoco Directional Survey Handbook

BPA-D-004

) * $ *" ) *! " + The function of the Well Location Memorandum is discussed in more detail in Section 6.3

# - # # " ) * $ *" ) * , * )$) )- ).

& ! - #

" ) * $ *" $ *! , * )$) )- ). DGPS and other surface positioning systems are described in Section 3.1

$ . $*!/ - - #

# ! 0 % * #

- . 1 2/ !) $ *" ) /" $ &))$

3 )"

C-2 Data and Work Sheets

September 1999 Issue 1

BP Amoco Directional Survey Handbook

BPA-D-004

!) $ *" ) /" &) 0 $

% * 0 - 4 . 5 6/ +!1)2 !*/! $ &))$

3 ! 4 % ! 4 % * "$ * *" " $!+ $ *" &))$

- 7 - # 3 0 ! 4 % * )" $ *" !* !) * )" ) ! $ )

$ 8

# % * "*" * " ) ## "*" *" *! " ) !) *!$

& 9 1 8

.+' - ,/ : .+' - ,/ & - . 5 ;/ 4 % ! 4

September 1999 Issue 1

Data and Work Sheets C-3

BP Amoco Directional Survey Handbook

BPA-D-004

* $* )! 3 ) * *" ! 0 *!0 &))$

" - 0 . 6 2 6 6/ < - !) $ *" +!1)2 & " 3**0 & "/) !)4+) $

" = 8

# 8

C-4 Data and Work Sheets

September 1999 Issue 1

BP Amoco Directional Survey Handbook

BPA-D-004

WELL LOCATION MEMORANDUM LOCATION DESIGNATION

This WLM supersedes the following previous locations: (NB: Any change in shotpoint location must have a new location designation)

Country: Region/State:

Prospect/Field: Lease/PSC/Block:

1. WELL LOCATION DEFINITION (To be completed by Buisiness Unit subsurface and/or reservoir team) SURFACE LOCATION: PRIMARY DEFINITION: 3D, 2D, HR Seismic Survey or OTHER* (* Circle appropriate definition)

Survey name:

Survey mnemonic:

Database type & name:

3D Inline bin, or 2D/HR line number:

Acquisition contractor & year:

3D Xline bin, or 2D/HR shot number:

Processing contractor & year:

3D bin size (Inline x Xline): or 2D/HR shotpoint interval:

OTHER DEFINITION (eg: template & slot No.):

SECONDARY DEFINITION: 3D, 2D or HR* Seismic Survey (* Circle appropriate definition)

Survey name:

Survey mnemonic:

Database type & name:

3D Inline bin, or 2D/HR line number:

Acquisition contractor & year:

3D Xline bin, or 2D/HR shot number:

Processing contractor & year:

3D bin size (Inline x Xline): or 2D/HR shotpoint interval:

PRIMARY DRILLING TARGET LOCATION (for non-vertical wells): PRIMARY DEFINITION: 3D, 2D or HR* Seismic Survey (* Circle appropriate definition)

Survey name:

Survey mnemonic:

Database type & name:

3D Inline bin, or 2D/HR line number:

Acquisition contractor & year:

3D Xline bin, or 2D/HR shot number:

Processing contractor & year:

3D bin size (Inline x Xline): or 2D/HR shotpoint interval:

Section 1 completed by:

Section 1 approved by:

Signature:

Date:

Name:

Position/Job Title:

September 1999 Issue 1

Data and Work Sheets C-5

BP Amoco Directional Survey Handbook

BPA-D-004

Well Location Memorandum - Page 2

LOCATION DESIGNATION

SUBSURFACE DATA (To be completed by Business Unit Subsurface Team)

Attach a separate map sheet to this WLM showing seismic lines and geological structure around target location

Describe below in words and diagramatically the surface location and it's constraints (give dimensions):

Proposed Location

TOLERANCE

Define Surface Location Tolerance(s)

Surface Location Area Diagram Illustrate shape and size of the zone within which a surface location would be acceptable and indicate constraints which limit rig anchoring or manoevring (eg: shallow gas, obstructions, pipelines).

For location(s) derived from workstation provide: Coordinates of surface and primary target locations and two other bins remote from the primary target (one bin with same Inline and one with same Xline bin number as primary target)

Location

3D Survey Name

Bin Size

Inline

Xline

Eastings

Northings

Eastings

Northings

Surface: Primary Target: Same Inline: Same Xline: For surface and target locations based on 2D or HR seismic provide: 2D/HR Survey Name Line No. Shotpoint Point* Location Surface: Primary Target: * Mapped point type (SP, CDP, etc) Attach extract of relevant 2D and/or HR line from database listing shotpoint coordinates values for 2km either side of proposed location

C-6 Data and Work Sheets

September 1999 Issue 1

BP Amoco Directional Survey Handbook

BPA-D-004

Well Location Memorandum - Page 3

LOCATION DESIGNATION

3. WELL LOCATION COORDINATES (To be completed by UTG SURVEY GROUP) LOCATION COORDINATES SURFACE LOCATION (Vertical or Deviated well)

PRIMARY TARGET LOCATION (Deviated well)

Latitude:

Longitude:

Eastings:

Northings:

Surface Positioning Tolerance:

True azimuth from surface location:

Water depth:

Horizontal offset distance:

degrees m

Ground Elevation:

Geodetic Information: Datum name:

Datum mnemonic:

Ellipsoid name:

Ellipsoid mnemonic:

Projection name:

Projection mnemonic:

Zone:

Data source of coordinates (eg: database name, report, etc): Surface Location: Primary Target Location:

Seismic survey positioning systems and horizontal accuracy estimates:

Surface Location Positioning System

Primary Target Location Accuracy

Positioning System

Accuracy

3D Seismic: 2D Seismic: HR Seismic: Other positioning information:

Section 3 completed by:

Section 3 approved by:

Signature:

Date:

Name:

Position/Job Title:

Circulation: D.S. / S.D.E. / D.E.

Site Investigation Specialist

Subsurface Team Leader Asset Geoscientists

Data Administrator (load to database) Head of Survey

September 1999 Issue 1

Data and Work Sheets C-7

BP Amoco Directional Survey Handbook

BPA-D-004

" ) * $ *" ) * )- )

! " # # $%&'$%(#%)* ##%+,

! " 2

" # $ % & '(%)* " ($ -& --' 0)

+ ,- . /0%( 1

2 * 2

" ( 0 %'# " # #70 %/ ' *

+3 4 5 64 $ 1

'8# 2 ( '78$ % (9% : / + #1' ; < ! ' /

! '%- '

! '

(#'-$ (-'-$ =9: , 2

2 ! - '-Â° ' -. )+/ " - ! 0 ! 12+ ! 0

! 0 . 3 " 4.

#) 2 2 =9: '%

2 2 ! /'- '

: 2 6 > ' 0 5 6 4

? ' %-78

, " 4 /007

! " ## $$ %%& ' ()

C-8 Data and Work Sheets

September 1999 Issue 1

Area:

Lat:

(Geogs: 2 dec places, Grid: 1 dp (m) 0 dp (ft)) Â° Long:

Ac c e p t e d S u r f a c e P o s i t i o n

& & ( '

Geodetic Datum Easting: Radius of error: System/method for accepted position

Projection and zone: !

Northing: & & Primary Positioning System (Geogs: 3 dec places, Grid: 2 dec places) Names of Reference Station(s) used for Primary Position

)*+$, -.

Secondary positioning

%# +$, -.

system:

01 12

Rig positioning contractor: Job number: Site survey date:

Long: Sph. Ht.

Contractor: Report number:

Coords of rotary: Local Datum Lat: Â° Long: Â° & Ellip. Ht.

or stated Vert Datum

RTE

B.L.A.T. A.M.S.L

& &

' ' '

S.D.

dY: ' rY:

dZ: ( ' rZ: ( &

Scale Factor: //' Useful Information / Notes

Â° Â°

3$4 + ' '/$% 5 6* 7 83 9$%%$ '4 ! 4 ! $%% 4# #$ ! + #3 $ #$ ! % : * 7 !56 ) # %% 5$! # 4 43 ;! correct.

Sph.Ht.

Easting:

Â° Â° & & &

S.D. S.D.

GPS Antenna

GPS Antenna 56

Rig Hdg 309.7 deg T

dX: ' rX:

' < Â° Coords of rotary: Local Datum

Northing Diagram

Diagram

Reciprocal flattening 1/ Datum Shift From WGS84 to Local Datum

S.D. X: Y: Z: Offset: Antenna to rotary (Rel. range/bearing)

Lat. Long

"!# ! #$ ! % & '

42 .55

.3 m

R/T

Rig Hdg 309.7 deg T

Completed by: (block caps)

1 " 7

Checked by: (block caps)

R/T

BPA-D-004

Data and Work Sheets C-9

Water depth

& & & &

Easting: Northing:

WGS84 Datum

Lat. Long

& ' < Â° ! 2 : %

Ref.Stn.2: Name/Country: Lat. Long. Easting Northing Dist to Ref.Stn.

Easting Northing Dist to Ref.Stn. Antenna Coords: Network Solution

Offset: Antenna to rotary (Relative range/bearing)

B.M.S.L.

Northing

Type of rig: Vertical datum:

Easting Dist to Ref.Stn.

Associated Ellipsoid Semi-major axis Semi-minor axis

Ref.Stn.3: Name/Country: Lat. Long.

Â° Â°

! 0 3

Ref.Stn.1: Name/Country: Lat. Long.

1. 0

Rig name:

Antenna Position: WGS84 Datum Lat:

Well Number:

Submit to BP Amoco Survey for checking/approval Location designation: Date Completed: Secondary Positioning System Contractors report no. (Geogs: 3 dec places, Grid: 2 dec places) Geodetic Parameters Â°

17 .4 m

Prospect/Field:

BP Amoco Directional Survey Handbook

September 1999 Issue 1

Country:

BP Amoco Directional Survey Handbook

BPA-D-004

WELL PLAN DATA SHEET Rig / Platform / Drill Site*

Well

Sheet completed by SURFACE LOCATION

Date Datum/Ellipsoid

planned / actual*

Structure reference Lat. Long.

Description

Well reference point Lat. Long. Offset from structure ref.

Description

N / S* E / W*

N / S* E / W* N / S*

Elevation (land rig) Drill datum RT / KB* Drill datum to well ref. pt. Well ref. pt. to MSL TARGET #1 Name Easting Northing Depth TVDss Tolerance

* delete as appropriate

Projection

Easting Northing

Easting Northing E / W*

Elevation (offshore) Drill datum RT / KB* Drill datum to MSL Drill datum to well ref. pt. TARGET #2 Name Easting Northing Depth TVDss Tolerance

Survey reference True / Grid* Grid convergence (T to G) Magnetic declination (T to M) Magnetic model Date Correction (magnetic to survey ref.) Correction (true to survey ref.)

TARGET #3 Name Easting Northing Depth TVDss Tolerance

North arrows (diag.) E / W* E / W*

Curved conductors Drill datum to well reference point MD TVD North East N / S* E / W* Incl. at w.r.p. Azim at w.r.p.

C-10 Data and Work Sheets

September 1999 Issue 1

BP Amoco Directional Survey Handbook

BPA-D-004

WELL PLAN DATA SHEET Rig / Platform / Drill Site*

Well

Sheet completed by

Date Datum/Ellipsoid

planned / actual*

Structure reference Lat. Long.

Description

Well reference point Lat. Long. Offset from structure ref.

Description

$Â°, - % $. N / S* $$Â° %- . E / W*

0 , $$ 0 , ,1 %% -

" 4! 5 + 6

!"# $%%

+ Easting Northing

Projection

&' () *

/ 0 , $ 1 0 ,$%1$ 1

+ $ (+ ! 2 3* $Â°, - % . N / S* Easting / 0 , $ $

$$Â° %- % . E / W* Northing 0 ,$%1 %

% - N / S* 1 % - E / W*

Elevation (land rig) Drill datum RT / KB* Drill datum to well ref. pt. Well ref. pt. to MSL

SURFACE LOCATION

TARGET #1 Name Easting / Northing Depth TVDss Tolerance

* delete as appropriate

Elevation (offshore) Drill datum RT / KB* Drill datum to MSL Drill datum to well ref. pt. TARGET #2 Name Easting / 0 , Northing 0 , ,$ Depth TVDss Tolerance

, % , $ , $ , %

Survey reference True / Grid* Grid convergence (T to G) Magnetic declination (T to M) Magnetic model 77' Correction (magnetic to survey ref.) Correction (true to survey ref.)

4 4 4 4

, 1 , ,$ , , , ,

,1Â° E / W* Â° E / W* Date 8

,Â°

,1Â°

1 $% -

TARGET #3 Name Easting Northing Depth TVDss Tolerance

North arrows (diag.)

decl. = +0.11 conv. = +2.34

Curved conductors Drill datum to well reference point MD TVD North East $ - $% - % 1- N / S* - E / W* Incl. at w.r.p. 1 Â° Azim at w.r.p. %$ $Â°

September 1999 Issue 1

Data and Work Sheets C-11

BP Amoco Directional Survey Handbook

BPA-D-004

DIRECTIONAL DESIGN CHECK LIST Rig / Platform / Drill Site

Well Date

Sheet completed by Checked by

Well Objectives Document from BU sub-surface team Updates to well objectives

Comment

Well Location Memorandum Planning File Well Plan Data Sheet Survey Program Data Sheet Proposed well trajectory BU sub-surface approval of trajectory Target analysis (1 per target) Offset well data (surveys, completion diags. etc.) Initial clearance scan (global scan) Tolerable Collision Risk Worksheet(s) Minimum separation calculations Anti-Collision Instruction Sheet Magnetic interference prediction Relief well contingency calculation Dispensations from Recommended Practice Wellsite Drawings Plan view drawings Vertical section drawings Structure (spider) plots Travelling cylinder - global clearance scan Travelling cylinder - working drawing(s) Travelling cylinder - wellsite plots

C-12 Data and Work Sheets

September 1999 Issue 1

BP Amoco Directional Survey Handbook

BPA-D-004

DIRECTIONAL DESIGN CHECK LIST Rig / Platform / Drill Site

Well

Date

Sheet completed by Checked by

+9:

Well Objectives Document from BU sub-surface team Updates to well objectives

Comment

5 ! ! ! #; < =; , !" !=

< = 9!: 5: :!9 ;

Well Location Memorandum

Planning File Well Plan Data Sheet Survey Program Data Sheet Proposed well trajectory BU sub-surface approval of trajectory Target analysis (1 per target)

Offset well data (surveys, completion diags. etc.) Initial clearance scan (global scan) Tolerable Collision Risk Worksheet(s) Minimum separation calculations Anti-Collision Instruction Sheet

9 : = 3:! "!9 ! ! 3

Magnetic interference prediction

+ + > ":= 6

Relief well contingency calculation

Recommended Practice Dispensation Form(s)

!" =):3 = 8

Wellsite Drawings Plan view drawings Vertical section drawings Structure (spider) plots

? " @6:" 3

Travelling cylinder - global clearance scan Travelling cylinder - working drawing(s) Travelling cylinder - wellsite plots

September 1999 Issue 1

8 " : = % < = 9!:

+ + > ":= 6

Data and Work Sheets C-13

BPA-D-004

C-14 Data and Work Sheets

SURVEY PROGRAM DATA SHEET Rig / Platform / Drill Site Survey Tool / Error Model

Well Hole Size

Program version Casing Size

Depth interval from to

Sheet completed by

Date

Comments / Contingency

BP Amoco Directional Survey Handbook

September 1999 Issue 1

Rig / Platform / Drill Site

Well

Date

Hole Size

! " " #

%&%'

! " " #

% $

" ( ( ) * "* !+ , * ,

-. ! !

% $

! "/ ) , " , () # " ! # , " * )) # +) / (

-. 0 1 !+ " , "

%&%'

& $

Comments / Contingency

! "/ ) , " , () # " ! # , " * )) # +) / (

BPA-D-004

Data and Work Sheets C-15

-. 0 1 !+ " , "

Depth interval from to

Sheet completed by

Survey Tool / Error Model

2 " ! ! !# + -() # "

Casing Size

Program version

BP Amoco Directional Survey Handbook

September 1999 Issue 1

SURVEY PROGRAM DATA SHEET

BP Amoco Directional Survey Handbook

BPA-D-004

ANTI-COLLISION INSTRUCTION SHEET Rig / Platform / Drill Site

Well Date

Sheet completed by BU authorisation

The instructions given in this sheet are based on: Well plan no. Date

999 Survey program no.

Date

and are not otherwise valid. Wells to be Shut In Well name

Minor Risk Wells Well name

Slot

Minimum Shut-in Interval MD from MD to

TCR*

Comment

Key Assumptions

*Tolerable Collision Risk

Travelling Cylinder Plots Plot no. Depth from Depth to

Date

Comment

Contingency Plans / Special Instructions

C-16 Data and Work Sheets

September 1999 Issue 1

BP Amoco Directional Survey Handbook

BPA-D-004

ANTI-COLLISION INSTRUCTION SHEET Rig / Platform / Drill Site

Well

Date

Sheet completed by BU authorisation

A:9 2 "

The instructions given in this sheet are based on: Well plan version no. Date

Survey program version no.

Date

and are not otherwise valid. Well Shut-ins Well name

Minimum Shut-in Interval MD from MD to

Slot no.

Minor Risk Wells Well name

$ $ -

, -

TCR*

Comment

# ?! ! 6 :) . ! := : ! B

Key Assumptions

*Tolerable Collision Risk

Travelling Cylinder Plots Plot no. Depth from Depth to

$ , 1 -

, 1

Date

1 1

Comment

Contingency Plans / Special Instructions

5 ! 2 = !== 3 ! B B ( * " 9!:= ) B:= : : = ) " = := = 6 := 2 !# = 2C > ": := !9 = !38: ) :" : =! ": " B : := . ! := ! " ! ( -* D B ! , - ' :! " !6 : = " !8 :3!= 9 ! 6" = !"C :" : =! ": " 9!# ": !9 !B!" ) 9! " 2!2: : C ) : : =

September 1999 Issue 1

Data and Work Sheets C-17

BP Amoco Directional Survey Handbook

BPA-D-004

DISPENSATION FROM RECOMMENDED PRACTICE To be used for recording planned violations of standard directional and survey procedures and recommended practices

Rig / Platform / Drill Site

Well Date

Sheet prepared by Recommended Practice Document

Procedure / Standard to be violated

Details of Dispensation Requested

Justification

Attachments

Technical Assessment / Recommendation

Signature / Date / Comment

BU Authorisation

C-18 Data and Work Sheets

September 1999 Issue 1

BP Amoco Directional Survey Handbook

BPA-D-004

DISPENSATION FROM RECOMMENDED PRACTICE To be used for recording planned violations of standard directional and survey procedures and recommended practices

Rig / Platform / Drill Site

Well

Date

Sheet prepared by

=3C +9: