Case Study :

History Matching of Well by Predictive Material Balance

Term Project : Advanced Reservoir Engineering

Presented By,

Namit J Jaiswal

B.E (Chemical)

December 18, 2003

Fairbanks, Alaska

OUTLINE

What is history matching ?

Methods used for history matching

Case description

Solution Scheme

Results

Conclusion and Recommendation

What is history matching ?

History Matching is the procedure for determining parameters in a reservoir model from observed production data.

History Matching

Process in reservoir

Levels of aquifer support

Bypassed zone

identification

Paths of fluid migration

TYPES

Manual

Automatic

Case Description

Reservoir type: Volumetric under saturated reservoirConnate water: 37 %Porosity: 21.5 %Drained Area by each well: 40 acresThickness of pay zone was given by isopach maps of both zones.

Well K, Zone 1 K, Zone 25-6 5.1 4.08-16 8.3 6.89-13 11.1 6.014-12 8.1 7.6

Laboratory core permeability measurements

Solution Scheme

1. Model Development

2. Initialization

3. History Matching

1. Model Development

Oil In place Material Balance

Tracy’s Model

Flow equation

Oil In-Place

oi

wi

B

SAhN

)1(7759

Material Balance

giggi

oigsosoioio

gsoon

BBB

mBBRRBB

BRB

giggi

oigsosoioio

gg

BBB

mBBRRBB

B

giggi

oigsosoioio

w

BBB

mBBRRBB

1

Calculation of these

avegn

gjpnjpp R

GNNN

)1()1(

pjppj NNN )1(

oi

pwwL B

B

N

NSSS 01)1(

Equation cont.

ggo

oogsoj Bk

BkRR

Equation cont.

Compare and iterate

Flow Equation

75.0ln

00708.0

w

e

wf

oo

oo

r

r

pp

B

hkq

o

p

q

Nt

2. Model Initialization

Permeability ratios

PVT data

Isopach Plots

Production History

Permeability data for cores

Given DATA

History Matching

Modified Parameter

kg/ko

kro

H

Absolute permeability

Results (5-16 Well )

WELL Zone (1) Zone (2) Zone (1) Zone (2) Zone (1) Zone (2)

5-6 5.3 4.1 8.2 13.3 43.46 54.53

DATAAverage Absolute Permeability to Air

(md)

Average Thickness of Pay zone (ft)

Capacity (ft)

5-16 Well Production History Matching

0

10

20

30

40

50

60

0 1 2 3 4 5 6 7 8Time,years

Oil

prod

uctio

n,st

b/da

y

0

200

400

600

800

1000

1200

1400

GO

R, s

cf/s

tb

Actual Production Modeled Production Actual GOR Modeled GOR

WELL Zone (1)Zone (2)

Zone (1)

Zone (2)

Zone (1)

Zone (2)

8-16 8.3 6.6 10.5 11.0 87.15 72.6

DATA

Average Absolute

Permeability to Air (md)

Average Thickness of Pay zone (ft)

Capacity (ft

Result Well (8-16)

8-16 Well Production History Matching

0

10

20

30

40

50

60

0 1 2 3 4 5 6 7 8 9

Time,years

Oil,

stb/

day

0

200

400

600

800

1000

1200

GO

R. s

cf/s

tb

Actual Oil Production Modeled Production Actual GOR Modeled GOR

WELLZone (1)

Zone (2)Zone (1)

Zone (2)

Zone (1)

Zone (2)

9-13 11.1 6 15 11166.

566

DATAAverage Absolute Permeability to Air

(md)

Average Thickness of Pay zone (ft)

Capacity (ft)

Result Well (9-13)9-13 Well Production History Matching

0

10

20

30

40

50

60

70

80

0 1 2 3 4 5 6 7 8

Time,years

Oil

prod

uctio

n,St

b/da

y

0

200

400

600

800

1000

1200

1400

Actual Oil Production Modeled Production Actual GOR Modeled GOR

WELLZone (1)

Zone (2)

Zone (1)

Zone (2)

Zone (1)

Zone (2)

14-12 8 7.5 6 11 48 82.5

DATA

Average Absolute

Permeability to Air (md)

Average Thickness of Pay zone (ft)

Capacity (ft)

Results Well (14-12)

14-12 Production History Matching

0

10

20

30

40

50

60

0 1 2 3 4 5 6 7 8 9

Time, years

Oil

prod

uctio

n st

b/da

y

0

200

400

600

800

1000

1200

GO

R, S

CF/

STB

Actual Oil Production Modeled Production Actual GOR Modeled GOR

c

Conclusion

Reasonable and Defendable Model

Tarner Tracy is fine for this problem