E (I-1D) Fluid Statics & Fluid Distribution

8/11/2019 E (I-1D) Fluid Statics & Fluid Distribution

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Copyright 2008, NExT, All rights reserved

Basics of Reservoir Engineering Module I

I.1.D Fluid Statics in the Reservoir and Fluid Distribution


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Fluid Distribution and Fluid Contact Estimation

So

Gas

Water

Oil

500

depth


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Reservoir Statics, Fluid Distribution and Capillarity

A B

o

w

1

2

3Pc = 0

Pressure

Depth

wo


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Uses of Capillary Pressure Data

Determine initial water saturation in the reservoir

Determine fluid distribution in reservoir

Determine residual oil saturation for

water flooding applications

Determine pore size distribution index

May help in identifying zones or rock types

Input for reservoir simulation calculations.

Decreasing

Permeability

A B

C

20

16

12

8

4

00 0.2 0.4 0.6 0.8 1.0

Water Saturation

CapillaryP

ressure



Fluid Contacts and Capillarity

(after Dandekar)



Relation Between Capillary Pressure and Fluid

Saturation

Free Water Level

Pc

Pd

Water-oil contact

Hd

HeightAboveFreeWate

rLevel(Feet)

0 50 100Sw(Percent)

0 50 100Sw(Percent)

0



Fluid Distribution in Petroleum Reservoirs

Gas & Water

Gas density = g

Oil, Gas & Water

Oil & Water

Oil density = o

Water

Water density = w

A

h1

h2

B

Free Oil Level

Free Water Level

Capillary pressure difference between

oil and water phases in core APc= h1g (w-o)

Capillary pressure difference between

gas and oil phases in core B

Pc= h2g (o-g)



Fluid Distribution

VCL

dec0 1

0 VCL

VCL 1

ILDC

ohmm0.2 200

RHOCN

us/f1.65 2.65

CNLLSS

0.6 0

DTC

us/f135 55

RHOCN CNLLSS

GAS

us/f1 0

BVW

dec1 0

OIL

1 0

BVWG1 0

SW

dec1 -1

10750

10800


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45 7 lb =



Fluid Distribution Exercise 2

Mercury injection test using a reservoir core sample shows:

A lab test (mercury injection test) of a reservoir core sample shows:

345.7oil ft =

30000.885

11250.838

5760.731

3790.533

3240.375

2810.158

2340

Capillary pressure, psiMercury saturation

mercury , cS p

345.7oillb

ft =

362.43waterlb

ft =

Question: Since mercury is the non-wetting phase

in the lab experiment, does the data represent

drainage or imbibition?

Density Info:

25ow

dynescm

=

100amdynes

cm =

Reservoir Info: 30oow =

Lab Info: 140oam =

1. Plot the drainage capillary pressure for this reservoir.

2. Identify fluid contacts, oil zone, water zone, and transition zone on your plot.

3. Draw a cross-sectional diagram of the reservoir indicating zones and contacts.

4. Calculate height of oil-water contact (OWC) above the free water level in ft.

5. Calculate the thickness of the transition zone in ft.

Fl id Di ib i E i 2 S l i



Fluid Distribution Exercise 2 - Solution

Capillary Data:

847.90.11530000.885

317.90.16211250.838

162.80.2695760.731

107.10.4673790.533

91.570.6253240.375

79.420.8422810.158

66.1312340mercury

S ,air mercuryc psiwater

S ,oil waterPc psi

R f



References

1. Amyx, J.W., Bass, D.M., and Whiting, R.L.: Petroleum Reservoir

Engineering, McGrow-Hill Book Company New York, 1960.

2. Tiab, D. and Donaldson, E.C.: Petrophysics, Gulf Publishing

Company, Houston, TX. 1996.

3. Dake, L.P.: Fundamentals of Reservoir Engineering, Elsevier, 1979

E (I-1D) Fluid Statics & Fluid Distribution

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