Anti Stick-Slip Technology brochure by Tomax

ANTI STICK-SLIP TECHNOLOGY FOR SUB-SURFACE DRILLING APPLICATIONS

STRINGERS

ENLARGEMENT

ROUGH SEAS

PERFORMANCE

INTERVENTION

ANTI STICK-SLIP

TECHNOLOGY

Regulators for improving energy transfer are common to many areas of technology. Tomax has adapted such a solution to downhole drilling.

The patented Anti Stick-Slip Technology (AST) has contributed to effective drilling through more than 3 million feet of challenging rock.

FUNCTIONAL PRINCIPLE The AST consists of a mechanical-hydraulic converter placed in the lower part of the drill string. Under normal, stable conditions, the unit will transfer torque and weight to the bit as a passive part of the Bottom Hole Assembly (BHA). However, if the bit becomes unstable, the AST will intervene to regulate the forces and the bit’s depth of cut.

In practical terms, this means that the momentary response/closed-loop function of the AST prevents the escalation of local instabilities into destructive vibrations.

The tool functions continuously, and no reset is required.

STABILITY DOWNHOLE The value of Anti Stick-Slip Technology has been proven through a wide variety of downhole challenges, where the AST tool has prevented destructive vibrations while increasing penetration rates through improved drill bit efficiency. The technology is applicable for all types of drilling and milling operations and is equally suitable for use in vertical and deviated wells.

Increasing bit torque from the rock/ cutter interface will cause the AST to contract, offloading the weight on bit and reducing the depth of cut.

The tool will then extend and reapply weight to deliver a steady load.

WITH AST

WITHOUT AST

Few, if any vibration mitigation solutions have been through as many scientific tests as the Tomax AST. This picture is taken from the drillers chair on the IRIS, Ullrig in Stavanger. The tool is a 6 ž� XC-AST with integrated recording of the motion and absorber pressures.

ANTI STICK-SLIP

IMPLEMENTATION Use of the AST requires no changes to standard drilling practices.

The tool has a wide working range, which eliminates the need for time consuming surface parameter adjustments. Use of the AST does not require the presence of on-site service personnel.

AST VALUE The spring characteristics of the drill string will cause distortions to the delivery of power to the bit. It is easy to envision this by imagining what happens when the bit is lowered to bottom: the bit rotates steadily off bottom but will most likely stall as the cutters bite. This is both because a gentle lowering of a long string is difficult, and also because the string conveys no torque at this point.

With the cutters stuck in the rock, the torque needs time to build until the cutters slip and the bit turns.

Drilling science says that the severity of this stick-slip at the cutting interface is regulated by the axial compliance of the drilling system i.e. the freedom of the bit to move in the axial (up-down) direction. This way a BHA is capable of self- regulating stick-slip to a certain extent. Unfortunately this also affects the loading of the cutters and limits the drilling efficiency. The AST replaces the stick-slip mitigation from axial excitation by a dedicated mechanical regulator.

This makes the stick-slip mitigation far more precise and provides for a relative improvement in drilling efficiency.

DRILLING EFFICIENCY 0,6 The use of AST for stick-slip mitigation is observed to improve drilling efficiency as much as 50% and more in difficult sediments.

0,5 0,4 0,3 0,2 0,1 0 Self regulated BHA

AST BHA

“Vibration reduction – success, ROP improvement – success.

Tool performance was highly noticed on the MWD vibration readings and while drilling data transmission.”

Anadarko did about 30 well sections with AST Offshore Mozambique

CASE EXAMPLE

MAINTAINING A SHARP EDGE IN HARD ROCK In hard stringers, more force is required to engage the cutters. As a result more heat is generated, thereby reducing the wear and impact resistance of PDC cutters. The inclusion of an AST tool in the BHA allows the use of more aggressive cutting structures to maximize drilling efficiency in terms of increased penetration rates and PDC durability.

The efficiency of a drill bit is generally determined by how sharp the cutter is. A sharp cutter requires less force to engage the rock and consequently creates less friction.

TIME-DEPTH CURVES

0

5 OFFSET

10 AGGRESSIVE BIT AND AST

15 DAYS

20

25

30

The graph shows the radical ROP and durability potential in replacing the conventional heavy set bits with an aggressive PDC bit and AST. In this example the cutters used had minimal chamfer and drilled the entire section in one run. The geology was a mixture of shales and hard carbonates in the Central North Sea.

PLACEMENT IN BHA The optimum placement of the AST tool is on top of the non-magnetic portion of the BHA. This is the same for rotary steerable systems, downhole motors and rotary assemblies.

BHA configurations examples for RSS/Under Reamer BHA RSS/LWD BHA and motor BHA. For hard rock and high friction formations, a roller reamer above the AST is recommended.

MAXIMUM BENEFIT FROM PDC Analysis of vibrations from modern drilling systems tends to reveal borehole friction as an increasingly important factor. High friction results in the energy being bounced back up the string. The phenomenon is typically encountered when the Polycrystalline Diamond Compact (PDC) cutters are loaded up to engage hard stringers.

The AST will greatly improve the benefit from PDC technology by allowing the use of more aggressive cutters that require less weight on bit.

In addition to a reduction in vibrations, friction is reduced with less heat generated at the cutter interface, resulting in increased energy efficiency. Heat is the most important factor contributing to wear and impact resistance of PDC cutters.

4

Transverse Strength (GPa) TSP PDC

3 2 1 0

200

400

600 800 1000 Temperature (°C)

1200

1400

The PDC cutter has a great strength advantage over the rock when cool (2.4 Gpa or 340.000 psi), but the strength takes a dramatic dive with increased temperature. The main source of heat in the drilling situation is friction – which implies low friction results in longer bit life.

NO STALLS WITH DOWNHOLE MOTORS With the AST positioned above a drilling motor, any sudden reactive torque will cause the AST tool to immediately contract, reducing weight on bit and preventing the bit or mill from stalling. This function saves both time and equipment. Additional value is gained from reduced fatigue cycles in coiled tubing operations and a more controllable toolface orientation with steerable motors.

With an effective system for preventing stalls, the safety margin on the motor differential pressure can be lowered, enabling higher load limits with longer, more efficient runs.

COUNTERFORCE ASSISTED AST The patented counterforce assisted AST solution (XCAST) keeps the lower BHA and the drill-bit suspended in both axial and rotational directions at the critical moment when the first cutter touches the rock. As the load increases, the helix-telescope function of the Tomax AST (Anti Stick-Slip Tool) ensures a steady load within the capacity of the PDC cutters.

NEW This new and improved principle of operation will produce the first vital circles of cut free from chatter. As more of the cutters are engaged, a smooth bottom-hole pattern develops. When the full cutting face is engaged, the XC-AST system is practically offloaded, while the main springs in the AST system take over to keep the system in tune. Now the Weight On Bit (WOB) can be brought beyond the compressive strength of the rock to produce a fast yet safe ROP (Rate Of Penetration).

Conventional drill-strings have high inertias in both rotational and axial directions. Therefore heavy-set and often quite blunt drill-bits are preferred to prevent damage in hard rock. The downside of the heavy-set approach is the difficulty of providing enough WOB to properly engage the cutters in the hardest layers. The result is often long periods of ineffective, slow grinding and unpredictable bit life. The new XC-AST makes it safe to run a drill-bit that is sharp enough to stay engaged even in the hardest layers. A continuous cut at moderate WOB produces less heat and makes the cutter last longer.

The patented XC-AST solution keeps the lower BHA and the drill-bit suspended in both axial and rotational directions at the critical moment when the first cutter touches the rock.

CERTIFIED BRANCHES

NORWAY

UK

USA

NORWAY Tomax AS Travbaneveien 1, Forus P.O. Box 332, Forus NO-4067 STAVANGER NORWAY Call: +47 51 95 11 70 Email: tomax-norway@tomax.no

BRAZIL

All branches of Tomax are certified in accordance with ISO 9001-2008 by Det Norske Veritas.

UK Tomax UK Ltd. 2nd Floor East Wing, Migvie House, 23 North Silver Street, Aberdeen, AB10 1RJ, UK Call: +44 (0) 1224 561313 Email: tomax-uk@tomax.no

USA Anti Stick-Slip Technology LLC 4103 Chance Lane, Rosharon, TX 77583 USA Call: +1 281 431 7800 Email: tomax-USA@tomax.no BRAZIL Tomax do Brasil Av. da Assembléia, 10-1919, Centro Rio de Janerio – RJ, BRASIL Call: (21) 3497-5083 Email: tomax-brazil@tomax.no

9 ½” X-series AST TOOL SPECIFICATIONS: PARAMETER

METRIC

IMPERIAL

Length

3.44 m (XC 4,92m)

11.29’ (XC 16,14’)

Stroke

0.15 m

6”

Max. OD

241 mm

9.5”

Min. ID

72 mm

2 13/16”

Mass

1110 kg (XC 1220 kg)

2470 lbs (XC 2690 lbs)

Max. WOB operational

45 kdaN

100 klbs

Max. downhole torque

68 kNm

50 kftlbs

Max. RPM

As recommended from bit manufacturer

As recommended from bit manufacturer

Ultimate tensile load

536 kdaN

1180 klbs

Operational tensile load

280 kdaN

616 klbs

Max. internal pressure

690 bar

10 000 psi

Max. hydrostatic pressure

2000 bar

30 000 psi

Max. pump rate

6000 lpm

1600 GPM

Max. sand content

1%

1%

Max. DLS operational

14 deg/30m

14 deg/100ft

Max. temp. operational

200C

390 F

Connection top

API 7 5/8 REG box

API 7 5/8 REG box

Make up torque

100 000 Nm

74 000 ftlbs

Connection bottom

API 7 5/8 REG pin

API 7 5/8 REG pin

Make up torque

100 000 Nm

74 000 ftlbs Configurations: XD = Standard XC = Counterforce

8 ¼” X-series AST TOOL SPECIFICATIONS: PARAMETER

METRIC

IMPERIAL

Length

4.23 m (XC 5,17 m)

13.87’ (XC 16.96’)

Stroke

0.25 m

9.4”

Max. OD

209.6 mm

8.25”

Min. ID

70 mm

2.7”

Mass

820 kg (XC 1015 kg)

1808 lbs (XC 2230 lbs)

Max. WOB operational

45 kdaN

100 klbs

Max. downhole torque

48 kNm

35 kftlbs

Max. RPM

As recommended from bit manufacturer

As recommended from bit manufacturer

Ultimate tensile load

512 kdaN

1 151 klbs

Operational tensile load

260 kdaN

572 klbs

Max. internal pressure

690 bar

10 000 psi

Max. hydrostatic pressure

2000 bar

30 000 psi

Max. pump rate

5 650 lpm

1500 GPM

Max. sand content

1%

1%

Max. DLS operational

14 deg/30m

14 deg/100ft

Max. temp. operational

200C

390 F

Connection top

API 6 5/8 REG box

API 6 5/8 REG box

Make up torque

65 000 Nm

48 000 ftlbs

Connection bottom

API 6 5/8 REG pin

API 6 5/8 REG pin

Make up torque

65 000 Nm

48 000 ftlbs Configurations: XD = Standard XC = Counterforce

6 ¾” X-series AST TOOL SPECIFICATIONS: PARAMETER

METRIC

Imperial

Length

3.96 m (XC 4.75 m)

13.0’ (XC 15.6’)

Stroke

0.20 m

0.6’

Max. OD

171 mm

6.75”

Min. ID

53 mm

2.08”

Mass

625 kg (XC 640 kg)

1375 lbs (XC 1410 lbs)

Max. WOB operational

30 kdaN

66 klbs

Max. downhole torque

41 kNm

30 kftlbs

Max. RPM

As recommended from bit manufacturer

As recommended from bit manufacturer

Ultimate tensile load

327 kdaN

720 klbs

Operational tensile load

170 kdaN

375 klbs

Max. internal pressure

690 bar

10 000 psi

Max. hydrostatic pressure

2000 bar

30 000 psi

Max. pump rate

3500 lpm

925 GPM

Max. sand content

1%

1%

Max. DLS operational

20 deg/30m

20 deg/100ft

Max. temp. operational

200C (XT 220C)

390 F (XT 425F)

Connection top

NC 50 box

NC 50 box

Make up torque

40 000 Nm

29 500 ftlbs

Connection bottom

NC 50 pin

NC 50 pin

Make up torque

40 000 Nm

29 500 ftlbs Configurations: XD = Standard XT = High temp. (220C) XC = Counterforce

5 ¼” X-series AST TOOL SPECIFICATIONS: PARAMETER

METRIC

IMPERIAL

Length

3.95 m

12.96’

Stroke

0.25 m

10”

Max. OD

133 mm

5.25”

Min. ID

35 mm

1.38”

Mass

332 kg

730 lbs

Max. WOB operational

30 kdaN

66 klbs

Max. downhole torque

24 kNm

18 kftlbs

Max. RPM

As recommended from bit manufacturer

As recommended from bit manufacturer

Ultimate tensile load

225 kdaN

500 klbs

Max. internal pressure

690 bar

10 000 psi

Max. hydrostatic pressure

2000 bar

30 000 psi

Max. pump rate

1500 lpm

400 GPM

Max. sand content

1%

1%

Max. DLS operational

25 deg/30m

25 deg/100ft

Max. temp. operational

200C (XT 220C)

390 F (XT 425F)

Connection top

HT 38 box

HT 38 box

Make up torque

23 900 Nm

17 600 ftlbs

Connection bottom

HT 38 pin

HT 38 pin

Make up torque

23 900 Nm

17 600 ftlbs

Configurations: XD = Standard XT = High temp. (220C)

4 ¾” X-series AST TOOL SPECIFICATIONS: PARAMETER

METRIC

IMPERIAL

Length

3.68 m (XC 5.17 m)

12.07’ (XC 16.96’)

Stroke

0.25 m

10”

Max. OD

121 mm

4.75”

Min. ID

35 mm

1.38”

Mass

300 kg (XC 363 kg)

660 lbs (XC 800 lbs)

Max. WOB operational

15 kdaN

33 klbs

Max. downhole torque

13 kNm

9 kftlbs

Max. RPM

As recommended from bit manufacturer

As recommended from bit manufacturer

Ultimate tensile load

180 kdaN

400 klbs

Operational tensile load

55 kdaN

121 klbs

Max. internal pressure

690 bar

10 000 psi

Max. hydrostatic pressure

2000 bar

30 000 psi

Max. pump rate

1500 lpm

400 GPM

Max. sand content

1%

1%

Max. DLS operational

25 deg/30m

25 deg/100ft

Max. temp. operational

200C (XT 220C)

390 F (XT 425F)

Connection top

NC 38 box

NC 38 box

Make up torque

13 300 Nm

9 800 ftlbs

Connection bottom

NC 38 pin

NC 38 pin

Make up torque

13 300 Nm

9 800 ftlbs Configurations: XD = Standard XT = High temp. (220C) XC = Counterforce

TT-series AST TOOL SPECIFICATIONS: PARAMETER / TOOL SIZE O.D. Inches

1-11/16

2-1/8

2-7/8

3-1/2

I.D. Inches (mm)

0.62 (16)

0.67 (17)

0.78 (20)

0.98 (25)

Length ft (m)

4.9 (1.49)

4.6 (1.40)

4.3 (1.31)

4.4 (1.34)

Weight lbs (kg)

27 (12)

42 (19)

62 (28)

106 (48)

Tool Joint Max Opr Torque ft-lbs (Nm) Ultimate Tensile lbs (kN)

1” AMMT

1-1/2” AMMT

2-3/8” PAC

2-7/8” REG

200 (275)

400 (550)

1000 (1370)

1315 (1800)

49 000 (223)

54 400 (247)

124 000 (563)

207 900 (945)

Max Dog Leg Deg/100 ft (30m)

24

24

24

24

Max Temp F (C)

390 (200)

390 (200)

390 (200)

390 (200)

Sour Service

Yes

Yes

Yes

Yes

Air/Foam

Yes

Yes

Yes

Yes

MONITORING TOOL STATUS ON SITE A surface check should be performed if re-running the AST is considered.

The check consists of wiping clean the polished section and visually inspect for mechanical damage and wear, as well as fluid leakage.

The stipulated maximum IADC rotating hours on an AST tool is in general 200. API guidelines apply.

In practical terms, the tool should be laid out prior to a run that will result in accumulated rotating hours beyond the established limit. An exception is made in cases where a tool is suspected to have been subjected to abnormal conditions.

A check of the telescopic section should be done every time the tool goes through the rotary table. The tool is shipped with an elastic cover to protect the polished area during transport and rig handling.

NEW TECHNOLOGY

FOR A NEW ERA The continuous search for hydrocarbons is moving the drilling industry into new, unknown environments. With this expansion, the ­uncertainty inherent in sub-surface formations implies increasing economic risk. The AST is an effective way to reduce this increased risk while increasing the overall rate of penetration.

RENDER.NO

LOCATIONS NORWAY Tomax AS Travbaneveien 1, Forus P.O. Box 332, Forus NO-4067 STAVANGER, NORWAY Call: +47 51 95 11 70 Email: tomax-norway@tomax.no UK Tomax UK Ltd. 2nd Floor East Wing, Migvie House, 23 North Silver Street, Aberdeen, AB10 1RJ, UK Call: +44 (0) 1224 561313 Email: tomax-uk@tomax.no USA TOMAX Drilling Technology LLC 4103 Chance Lane, Rosharon, TX 77583, USA Call: +1 281 431 7800 Email: tomax-USA@tomax.no BRAZIL Tomax do Brasil Av. da Assembléia, 10-1919, Centro Rio de Janerio – RJ, BRASIL Call: (21) 3497-5083 Email: tomax-brazil@tomax.no SOUTH AFRICA Tomax Drilling Technology Cnr Lower Long St. & Hans Strijdom Road Foreshore, Cape Town 8001 Call: (27) 214121500 Email: helge.smedsvig@tomax.no

TOMAX.NO