PETE 310

Lecture # 17

Chapter 10 Properties of Black Oils

Reservoir Fluid Studies Lab Procedure

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 (CCE)

Differential Liberation Tests (DL)

Viscosity Measurements

Separator Tests

Compositional measurements

Fluid Properties Determined

Oil PropertiesBubble Point Pressure

BoRsBtCo and mo

Gas propertiesz

Bg and mgCompositions oil & gas

Oil Sampling Procedures

Bottom hole or subsurface samples

Pros

Cons

Separator Sampling

Pros

Cons

Surface Sampling

Bottom Hole Sampling

Preserved Samples

Reservoirs Conditions

Selective Sampling Zones

Sampling early in the life of the reservoir with minimum disturbance

Lower overall cost

Oil Sampling Procedures

Separator Samples

Cheaper

SAMPLE BEFORE

RESERVOIR PRESSURE

DROPS BELOW Pb

Temperature of Test = Reservoir Temperature

Vt1

Vt2

Vt3

=V

b

Vt5

Vt4

oil oil oiloil

oil

gas gas

Hg Hg HgHg

Hg

P1

>> Pb

P2

> Pb

P3

= Pb

P4

< Pb

P5

< P4

1 2 3 4 5

Flash Vaporization Test or Constant Composition Expansion Test (CCE)

Flash Vaporization Test (CCE)

Properties determined

Pb

Co

Determination of Pb

Determination of Co

Differential Separation Test (DL)

gas

oil

oil oiloil

oil

gas

Hg

Hg

HgHg

Hg

P 1 = P b P 2 < P b P 2 < P b P 2 < P b P 3 < P 2 < P b

1 2 3 4 5

gas

oil

Gas off

Temperature of Test = Reservoir Temperature

Differential Separation Test (DL)

Temperature of Test = Reservoir Temperature

Piston.swf

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 Rsdband below the bubble point pressure Rsd

Isothermal compressibility (derived property)

Separator Tests

Tests performed at a combination of different Temperature and Pressure pairs

Separator Tests

Goals: Maximize API, minimize BoSb & RsSb

Optimization of Separator 2 Conditions

3160

3180

3200

3220

3240

3260

3280

3300

So

lutio

n G

as O

il R

atio

at

Pb

(R

sb

)

2.76

2.78

2.80

2.82

2.84

2.86

Fo

rma

tio

n V

olu

me

Fa

cto

r a

t P

b (

Bo

b)

50 100 150 200 250 300

Separator 2 Pressure (psia)

High Pressure Separator @ 900 psia and

TSep2

= 75oF

100 F

Nomenclature

Compositional Tests

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