OFM_Fetkovich (oil field manager)

7/29/2019 OFM_Fetkovich (oil field manager)

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Fetkovich Transient & Decline Analysis

OFM 2004


2/23

2004 Schlumberger Information Solutions. All rights reserved.

Arps Equation for Exponential Decline

(((( ))))

tD

i

i

eqtq

====


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Decline Curve - Dimensionless Time

tDt idD


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Decline Curve - Dimensionless Rate

(((( ))))

idD

q

tqq


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Dimensionless Arps Equation

For exponential decline

dDt

dD eq

====


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Dimensionless - Exponential Decline

0.001

0.01

0.1

1

10

100

0.0001 0.001 0.01 0.1 1 10 100 1000

tdD

qdD


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Dimensionless Arps Equation

Hyperbolic decline

Harmonic decline

(((( ))))

b1

dD

dD

bt1

1q

++++

====

(((( ))))dDdD

t11q

++++====


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Dimensionless - Decline Type Curves

0.001

0.01

0.1

1

10

100

0.0001 0.001 0.01 0.1 1 10 100 1000

tdD

qdD

b=0

b=10.2

0.4

0.6

0.8


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Constant Pressure Production

2wat

Drc

kt006329.0t

====

(((( ))))wfiD

ppkh

qB2.141q

====

wa

eD r

r

R ====s

wwa err

====


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Constant Pressure Production

1.E-03

1.E-02

1.E-01

1.E+00

1.E+01

1.E+02

1.E+00 1.E+01 1.E+02 1.E+03 1.E+04 1.E+05 1.E+06 1.E+07 1.E+08

tD

q

D

R=20R=50

R=1000R=300R=100

R=inf.

R=10


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Fetkovich Solution

====

2

1

r

rln1

r

r

2

1

tt

wa

e

2

wa

e

DdD

====

21

rrlnqqwa

eDdD


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Fetkovich Solution

0.001

0.01

0.1

1

10

10 0

0.0001 0.001 0.01 0.1 1 10 100 1000

tdD

qdD


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Fetkovich Type Curve

0.001

0.01

0.1

1

10

100

0.0001 0.001 0.01 0.1 1 10 100 1000

tdD

qdD

Transient flow Boundary-dominated flow

b=0 b=1

0.2

0.4

0.6

0.8

RD=10

RD=1E6

2050

100300


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Dimensionless Variables

====

2

1

r

rln1

r

r

2

11

rckt006329.0t

wa

e

2

wa

e

2wat

dD

(((( ))))

==== 2

1

r

r

lnppkh

qB2.141

qwa

e

wfidD


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Drainage Radius Estimate

(((( ))))

dDwfidDte q

q

pph

B2.141

t

t

c

006329.0

2r


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Drainage Area and Original Oil-In-Place

43560rA2e====

(((( ))))

====

dDdDwfit

w

q

q

t

t

ppc

S1N


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Estimating Permeability and Skin Factor

(((( ))))(((( ))))

====

dDD

wfi q

q

2

1Rln

pph

B2.141k

D

ewa

R

rr ====

====

wa

w

r

rlns


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Estimating - Permeability and Skin Factor

(((( )))) (((( ))))

==== dDDwfi q

q

2

1

Rlnpph

B2.141

k

swwa err

====wa

eD

r

rR ====


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Applying the Fetkovich Type Curve

Plot rate vs. time on log-log scale

Identify transient and boundary-dominated flow

Move field data plot on type curve

Match field data to type curve

By hand

By Automatic Match


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Applying the - Fetkovich Type Curve

OFM

Select a convenient match point

Read the time match point (tdD, t)

Read the rate match point (qdD, q)

Select the early-time stem RD

Select the late-time stem b


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Estimate the drainage radius

Estimate the drainage area and

original oil in place

(((( ))))

dDwfidDte

q

q

pph

B2.141

t

t

c

006329.02r

43560

rA

2e====

(((( ))))

====

dDdDwfit

w

q

q

t

t

ppc

S1N


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If RD can be estimated from type curve match, estimate

permeability

Estimate apparent wellbore radius and skin factor

(((( ))))

(((( ))))

====

dDD

wfi q

q

2

1Rln

pph

B2.141k

D

ewa

R

rr ====

====

wa

w

r

rlns


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If RD cannot be estimated, estimate skin factor from

independent sourceEstimate apparent wellbore radius and RD

Estimate permeability

(((( )))) (((( ))))

====dD

Dwfi q

q

2

1

Rlnpph

B2.141

k

swwa err

====

wa

eD

r

rR ====

OFM_Fetkovich (oil field manager)

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