PETE 310 Lecture # 17 Chapter 10 – Properties of Black Oils - Reservoir Fluid Studies
Fluid Properties for Reservoir Engineering Processes The fluid properties of interest to the Reservoir Engineer are those that affect the mobility of fluids within the reservoirs these are used in material balance calculations Properties at surface conditions for transportation and sales (API, viscosity, oil quality)
Fluid Properties for Reservoir Engineering Processes PVT properties are determined from 5 specific lab procedures – – – – –
Flash liberation tests Differential Liberation Tests Viscosity Measurements Separator Tests Compositional measurements
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Fluid Properties Determined Oil Properties – – – – –
Bubble Point Pressure Bo Rs Bt Co and µo
Gas properties – z – Bg and µg
Compositions oil & gas
Oil Sampling Procedures Bottom hole or subsurface samples Separator Samples SAMPLE BEFORE RESERVOIR PRESSURE DROPS BELOW Pb
1.Flash Vaporization Test
V
2
V
t1
oil
3
V t3 = V b
1
t2
oil
4
5
gas V oil
gas V
t4
t5
oil oil
Hg
Hg
Hg
Hg Hg
P 1 >> P
b
P2 > P
b
P3 = P
b
P4 < P
b
P5 <P
4
Temperature of Test = Reservoir Temperature
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1.Flash Vaporization Test Properties determined â&#x20AC;&#x201C; Pb â&#x20AC;&#x201C; Co
Determination of Pb
Determination of Co
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2.Differential Separation Test Gas off 1
2
3
4
gas
5 gas
gas oil oil
Hg
oil
oil
Hg
oil
Hg
Hg P1 = Pb
P2 < Pb
oil
Hg P2 < Pb
P2 < P b
P3 < P
2
< Pb
Temperature of Test = Reservoir Temperature
2.Differential Separation Test Properties Determined – Oil formation volume factor at the Bubble Point pressure Bodb and below the bubble point pressure Bod – Solution gas-oil ratio at the Bubble Point pressure Rsdb and below the bubble point pressure Rsd – Isothermal compressibility (derived property)
3. Separator Tests Tests performed at a combination of different Temperature and Pressure pairs
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3. Separator Tests Goals: Maximize API, minimize BoSb & RsSb
Optimization of Separator 2 Conditions 3300
2.86
Solution Gas Oil Ratio at Pb (Rsb)
3280
2.84
3260 2.82
3240 2.80
3220 3200
2.78
3180 o T = 75 F 2.76 Sep2
3160 50
100
150
200
250
Formation Volume Factor at Pb (Bob)
High Pressure Separator @ 900 psia and 100 ยบF
300
Separator 2 Pressure (psia)
Comparison between 1 & 2 Separators Stages (volatile oil) 2.96
3440 One Separator Stage
3420
2.94
3400 2.92
3380
3360
Low Pressure Separator @ 300 psia and 75ยบF o TSep1 = 160 F
400
500
600
700
800
2.90 900
Formation Volume Factor at Pb (Bob)
Solution Gas Oil Ratio at Pb (Rsb)
3460
1000
Separator 1 Pressure (psia)
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Typical PVT Properties for a Black Oil and a Volatile Oil 3.2
Formation Volume Factor (Bo)
o T =180 F R
Black Oil Volatile Oil Black Oil Correlation
3.0 2.8 2.6 2.4 2.2 2.0 1.8 1.6 1.4 1.2 1.0
P b
P b 0
1000
2000
3000
4000
5000
Pressure (psia)
Typical PVT Properties for a Black Oil and a Volatile Oil 4000 o T =180 F R
Solution Gas Oil Ratio (Rs)
Black Oil Volatile Oil Black Oil Correlation
3000
2000
1000
0
P b
0
1000
2000
3000
P b
4000
5000
Pressure (psia)
Nomenclature
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4. Compositional Tests http://www.rpi.edu/dept/chem-eng/Biotech-Environ/CHROMO/chromintro.html http://www.rpi.edu/dept/chem-eng/Biotech-Environ/CHROMO/chroanim.html
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