IMPROVING DUAL POROSITY SIMULATION OF WATERFLOOD

PERFORMANCE IN THE NATURALLY FRACTURED SPRABERRY TREND

AREA

By Tanvir ChowdhuryTexas A&M University

Pioneer Natural Resources

• It is a very large field in areal extent (400,000 acres)

• A NFR with extensive vertical fractures

• Poor ultimate recoveryGlasscock Co

Reagan CoUpton Co

Midland Co

Martin Co Borden Co

Pioneer Natural Resources’ Pioneer Natural Resources’ Spraberry Unit PositionSpraberry Unit Position

Spraberry Trend AreaSpraberry Trend Area

Spraberry Trend Area

• Investigated the waterflood performance of an old (Humble Pilot) and a new (O’Daniel Pilot) Waterflood.

Find methods to extend and apply the results found from the Humble and O’Daniel Pilot simulations to all over the Spraberry Trend area

Presentation OutlineStep 1 Step 2

Applied

Simulation of tracer response from the

present waterflood pilot

Step 3

Field Simulation involving multiple wells

Confirmed

Previous StudiesPVT Study

Log Analysis Imbibition Study(Pc & Kr)

Pressure Transient AnalysisProduction Data Analysis

Core AnalysisOutcrop Study

Simulation of an old waterflood pilot (Humble

Pilot)

Permeability anisotropy and fracture orientation

Obtained

Simulation of The Humble Pilot

Step 1

22

Only two wells were included in the basic model, one is injector (SHB-10) and the other is producer (SHB-8) as shown in Humble Pilot map.

The production well was located in the same line with injection well (in the on-trend direction, along the primary fracture orientation).

The response of oil production rate in the SHB-8 well was only affected by water injection from the SHB-10 well.

Assumptions For Simulation

16

15

SHACKELFORD

HUMBLE

MAGNOLIA

“A”

10

9

15

8

17

16

20

21

TIPPET

TIPPET

TIPPET TIPPET

HUTT

UNION

HUMBLE “B”

SHACKELFORD

HUMBLE “B”SHACKELFORD

SHACKELFORDHUMBLE “B”

HUMBLE “B”

1 2

3

2

6

3

1

23

4

1

2

1

2

3

4

1

2

3

48

412

13

1

2

3

4

3

11

8

24

6107

5

1

9

Spraberry FractureSystem Schematic

Average fracture spacing3.17 ft (N42E)

Average fracture spacing1.62 and 3.8 ft (N32E and N80E)

Pay zone, 5USiltstone,

Vshl<15%,f>7%

Pay zone,1USiltstone,

Vshl<15%,f>7%

Non-pay zone,2U,3U, and 4U

Siltstone+Dolomite,

Vshl<15%, f <7%

Sand layer1U (10 ft)

Sand layer5U (15 ft)

Shale layer(140 ft)

Reservoir Properties

Oil-water Relative Permeability

0

0.2

0.4

0.6

0.8

1

0 0.2 0.4 0.6 0.8 1Sw

Kr

Krw (farcture)Kro (fracture)Krw (matrix)Kro (matrix)

0

5

10

15

20

25

30

0.0 0.2 0.4 0.6 0.8 1.0

Water Saturation (PV)

Cap

illa

ry P

ress

ure

(psi

g)

Fracture

MatrixVugs

Grid System

Matrix

Fracture

Comparison Between Observed and Simulated Results

Water cut vs. time BHP vs. time

0

200

400

600

800

1000

1200

1400

1600

0 200 400 600 800 1000 1200 1400Time (Days)

Wat

er I

nje

ctio

n R

ate

(ST

BW

/D)

Simulation ResultObserved Data

Water Injection Begins

0

0.2

0.4

0.6

0.8

1

0 200 400 600 800 1000 1200 1400

Time (Days)

Wat

er C

ut

(Fra

ctio

n)

Simulation Result

Observed Data

Water Injection Begins

0

500

1000

1500

2000

2500

3000

3500

4000

4500

5000

0 200 400 600 800 1000 1200 1400

Time (Days)

BH

P (

Psi

a)

Simulation Result

Observed Data

Water Injectio

n Begins

0

10

20

30

40

50

60

70

80

90

100

0 200 400 600 800 1000 1200 1400

Time (Days)

Pro

du

ctio

n R

ate

(ST

B/D

)

Simulation Result

Observed Data

Water Injectio

n Begins

Simulation of The Tracer Test Conducted in The O’Daniel Pilot

Step 2

N

O'Daniel

O'Daniel

O‘Brian

O'Daniel

O'Daniel

Brunson

Boone

O‘Brian

Powell

Floyd

35

33

B-1

D-1

C-1

5

7

12

913

10 63

9

812

7

A-1

B-1

1

A-5

Boon

e E-1 A-6

A-3A-7

32

12

8W

346

1

24

31

36

26

D-1

19

1330

G-1

C-2E-1

Boon

e A-1

D-1

A-1F-1

C-1

C-11

D-1

32

47

25

29

37

46C-1

28

4538

39

40

48 14

4143

4950

44

42

Production Well

Production Well Monitored During Tracer Test

Water Injector

CO2 Injector

Logging Observation Well

N

O'Daniel

O'Daniel

O‘Brian

O'Daniel

O'Daniel

Brunson

Boone

O‘Brian

Powell

Floyd

35

33

B-1

D-1

C-1

5

7

12

913

10 63

9

812

7

A-1

B-1

1

A-5

Boon

e E-1 A-6

A-3A-7

32

12

8W

34

6

1

24

31

36

26

D-1

19

13

30

G-1

C-2

E-1

Boone

A-1

D-1

A-1F-1

C-1

C-11

D-1

32

47

25

29

37

46C-1

28

4538

39

40

48 14

41

43

4950

44

42

Production Well

Production Well Monitored During Tracer Test

Water Injector

CO2 Injector

Logging Observation Well

RESPONSE OF SURROUNDING WELLS ON TRACER INJECTIONAT E.T O'DANIEL PILOT AREA

0.0

20,000.0

40,000.0

60,000.0

80,000.0

100,000.0

120,000.0

140,000.0

160,000.0

180,000.0

200,000.0

0 10 20 30 40 50 60 70 80 90 100

TIME (DAYS)

TR

AC

ER

CO

NC

EN

TR

AT

ION

(P

PT

)

WIW #47-Brunson D-1 WIW #46-Brunson D-1

WIW #45- Pilot Well #38 WIW #48-O'Daniel A-1

Time

Co

nce

ntr

ati

on

Co

nce

ntr

ati

on

Time

a) Typical Response b) Shape of The Actual Response From WIW#47 to O’Daniel D-1

47O'Daniel

Brunson

D-1

Model

1. Dual porosity with tracer option using Eclipse

2. Grid block is 100 x 100

3. Number of wells 2, one injector (E.T. O’Daniel #47) and one producer (Brunson “D” 1).

4. Rock and fluid properties from Humble Simulation model.

5. Tracer injection concentration is 158.9 ppm for 11.67 hrs.

O'Daniel O'Daniel

Brunson

D-1

47

25

29

37

46

45

3839

40

4814A-1

O'Daniel

35

33

3212

8W34

24

31

36

D-113

30

29

C-128

14

Production Well

Water Injector

History Match Result (W#47-Br.D-1): Kx/Ky= 84/15000Orientation 43 Deg.

0

20000

40000

60000

80000

100000

120000

140000

160000

180000

0 5 10 15 20 25 30 35Time (Days)

Co

nc

en

tra

tio

n (

pp

t)

Simulation Result Observed Data

O'Daniel

O'Daniel

O‘Brian

O'Daniel

O'Daniel

Brunson

Boone

O‘Brian

Powell

Floyd

35

33

B-1

D-1

C-1

5

7

12

913

10 63

9

812

7

A-1

B-1

1

A-5

Boon

e E-1 A-6

A-3A-7

32

12

8W

346

1

24

31

36

26

D-1

19

1330

G-1

C-2E-1

Boon

e A-1

D-1

A-1F-1

C-1

C-11

D-1

32

47

25

29

37

46C-1

28

4538

39

40

48 14

4143

4950

44

42

Fracture Orientation Obtained From The Tracer Test

Simulation of O’Daniel Unit and Surrounding Wells

Step 3

Model

1. Dual porosity with tracer option using CMG simulator

2. Grid block is 130 x 130 with 3 x 2 layers

3. The 8,383-acre area of the model contains 15 injectors and 44 producers

4. Rock and fluid properties were obtained from The Humble Simulation model.

O’Daniel Unit Simulation

Structural Map For The O’Daniel Unit Simulation

Model

1. The Structural map was scanned and digitized.

2. The digitized map is then uploaded to the CMG Gridbuilder to build the geological model

Building The Model

Spraberry FractureSystem Schematic

Average fracture spacing3.17 ft (N42E)

Average fracture spacing1.62 and 3.8 ft (N32E and N80E)

Pay zone, 5USiltstone,

Vshl<15%,f>7%

Pay zone,1USiltstone,

Vshl<15%,f>7%

Non-pay zone,2U,3U, and 4U

Siltstone+Dolomite,

Vshl<15%, f <7%

Sand layer1U (10 ft)

Sand layer5U (15 ft)

Shale layer(140 ft)

The Simulation Model

Results Obtained From Previous Studies

1. There are 3 layers in the model.

2. Only the first and the third layers contribute to the production and the middle layer is a non-producing shale layer.

O'Daniel

O'Daniel

O‘Brian

O'Daniel

O'Daniel

Brunson

Boone

O‘Brian

Powell

Floyd

35

33

B-1

A-1

Boone

E-1 A-6

A-3A-7

32

12

8W

34

24

31

36

26

19

13

G-1

C-2

E-1

Boone

A-1

D-1

F-1

C-1

47W

29

37W

46WC-1

28

45W38

39

40

48W 14W

10W

5W

16

21

2

7W

22

20W

1

27

23

3

4W9W

11W

McClintic

McClintic

E-1

E-42 E-32

8

McClintic

Brown

E.T. O’Daniel Unit

25W

30

D-1

Production Well

Water Injector

O'Daniel

O'Daniel

O‘Brian

O'Daniel

O'Daniel

Brunson

Boone

O‘Brian

Powell

Floyd

35

33

B-1

A-1

Boon

e E-1 A-6

A-3A-7

32

12

8W

34

24

31

36

26

D-1

19

13

30

G-1

C-2E-1

Boone

A-1

D-1

F-1

C-1

47W

25W

29

37W

46WC-1

28

45W 39

40

48W 14W

10W

5W

16

21

2

7W

22

20W

1

27

23

3

4W9W

11W

McClintic

McClintic

E-1

E-42 E-32

8

McClintic

Brown

E.T. O’Daniel Unit

38

Production Well

Water Injector

The Reservoir Model With Fractures

Fracture Water Saturation

Summary (Humble Pilot)

The fracture permeability values in the on-trend and off-trend directions of 15000 and 100 md, respectively, indicate that reservoir permeability is highly anisotropic.

The results obtained from this study support the previous analyses as follows:

The on-trend and off-trend permeability in the O’Daniel Unit are close to the value obtained from the Humble Pilot simulation.

The orientation of the fracture trend as determined by the tracer test agrees with the orientation obtained from historical production data, interference testing and horizontal core analysis.

Summary (Tracer Test)

For field simulation history matching, it is necessary to introduce existing fractures where there is not enough water production from off-set injectors.

It is possible to match most of the wells by using the permeability anisotropy (Kx/Ky) and fracture orientation obtained from the tracer simulation in the O’Daniel field model

Summary (O’Daniel Field Simulation)

The results of this work will provide a method to assess the economic feasibility of large-scale water injection in the remainder of the field.

Conclusions

The methods described here can be used to investigate areas of Spraberry where little or no water injection has occurred .