BureauofEconomic

Geology

APPLICATIONS OF 3-D SEISMIC TO EXPLORATION AND DEVELOPMENT

OF CARBONATE RESERVOIRS: SOUTH COWDEN GRAYBURG FIELD, WEST TEXAS

Stephen C. Ruppel, Yong-Joon Park, and F. Jerry Lucia

Bureau of Economic GeologyThe John A. and Katherine G. Jackson School of Geosciences

The University of Texas at Austin

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Geology

GEOLOGIC SETTING

MAJOR GRAYBURG RESERVOIRS

Permian Basin

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Geology

0 50 mi FT. STOCKTON

APACHE MTS

GUADALUPE MTS

CARLSBAD

N MEXTEXAS

1 2

3

4

5

6

7

89

10

13

14

15

DiabloPlatform

SIERRA DIABLO

11

12

16

N

Delaware

Basin

Midland

Basin

9

COWDEN NORTH

FOSTER

WADDELL

DUNE

MCELROY

BIG LAKE

WORLD

OLSON

FARMER

SOUTH COWDEN

78

10111213141516

9

GRAYBURG-JACKSON

VACUUM

EUNICE-MONUMENT

KEYSTONE

MABEE

MIDLAND FARMS

123456

GRAYBURG STRUCTURESouth Cowden Field

GLORIETA PLATFORM MARGIN

WELLS

CORED WELLS

16

1100

'

0 5000'

1500

'

1500'

43

1700'

37

CI = 50'

47

48

42

1

2

11

12

13

14

7

17

18

9

8

5

4

6

44

45

41

N

-1000' to -1450'

-1450' to -1600'

> 1600'

SEQUENCE ARCHITECTUREGrayburg Formation, South Cowden Field

Seq. boundary

High-freq. cycleTidal flat

Siltstone

Grain-dom. pack/gnstn

Fusulinid wackestone

Pel./skel. wacke/pkstn

QueenFm.

SanAndresFm.

Q1

Guad13

G4

G3

G2

G1

W E

2000

50 ft

00

ft

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Geology

N

0

0 5000 ft

1500 m

L arg e-s c ale an h y d r i te rem o v al ;c a lc i t e-l in ed v u g s

A ltered an h yd r i tean d g yp su m

No d u lar, p o ik i lo to p ic an dv o id -f i l l in g an h y d r i t e

Co r ed w el l s

O /W c o n t ac t

SULFATE DIAGENESISSouth Cowden Grayburg Reservoir

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Geology

ANHYDRITE DISSOLUTION Grayburg Formation, South Cowden Field

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PATTERNS OF SULFATE DIAGENESISSouth Cowden Grayburg Reservoir

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Geology

0

0

5000 ft

1000 m

Partly altered sulfate, good perm.Sulfate absent, highest perm.

Abundant sulfate, low perm.

High frequency sequenceCycle

200

00

60

ftm

No. 13-11 No. 9-17No. 8-12

No. 6-16

No. 6-20

O/W (-1850)

No. 7-1

No. 12-1

No. 7-4

Queen

Grayburg

DISTRIBUTION OF PORE TYPESAND PERMEABILITY

Permeability

OWC

kh < 100

kh 100 - 500

kh 500 - 1000

kh > 1000

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Pore Types

OWC

PILLARS

Permeability

OWC

PILLARS

kh < 100

kh 100 - 500

kh 500 - 1000

kh > 1000

Cumulative Production

< 100 Mbbl

100-500 Mbbl

> 1000 Mbbl

500-1000 Mbbl

OWC

PERMEABILITY AND PRODUCTION TRENDS

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UNDERPRODUCED AREAS

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3-D INTERPRETATION OF STRUCTURAL SETTING

SOUTH COWDEN FIELD STRUCTURETop Grayburg

1 mile

- 650 ms

- 700 ms

- 750 ms

- 800 ms

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Moss Unit

South Cowden Unit

OWC

Two-way Travel Time

Yates

Queen

Grayburg

U San Andres

NW SE

Clear Fork

500 ms

1000 ms

3-D SEISMIC STRATIGRAPHY South Cowden Field

1 mileBureau

ofEconomic

Geology

L

M

Lowstand wedge

Glorieta platform margin

Moss Unit survey South Cowden survey

Grayburg reservoir

- 650 ms

- 750 ms

- 850 ms

- 1050 ms

- 950 ms

- 600 ms

- 650 ms

- 700 ms

- 800 ms

- 750 ms

OWC

Moss Unit

S. Cowden Unit

Foster Unit

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Geology

DEVELOPMENT OF RESERVOIR STRUCTURE

Top Clear Fork Structure Top Grayburg Structure

2 miles

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3-D DELINEATION OF RESERVOIR POROSITY

600 ms

700 ms

800 ms

SEISMIC RESOLUTION OF RESERVOIR POROSITYAmplitude

San Andres

Grayburg

MainPay

Zone

Queen

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700 ms

800 ms

1 mile

GR DT

16-3A Grayburg

San Andres

HORIZON SLICING OF RESERVOIR INTERVAL

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W E

- 5ms-10ms-15ms-20ms

Queen

MAP OF SEISMIC AMPLITUDE

Maximum Negative Amplitude20 ms window

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2 mile

strong

weak

OWC

NEGATIVE AMPLITUDE ARCHITECTURE

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+

_

700 ms

800 ms

GR GRDT DTNW SE

San Andres

Grayburg

Queen

COMPARISON OF SEISMIC AMPLITUDE AND CALCULATED PERMEABILITY

Negative Amplitude (20 ms)

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2 mile

Permeability

OWC

kh < 100

kh 100 - 500

kh 500 - 1000

kh > 1000

strong

weak

OWC

PILLARS

COMPARISON OF SEISMIC AMPLITUDE AND CUMULATIVE OIL PRODUCTION

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2 mile

Negative Amplitude (20 ms) Cumulative Production

< 100 Mbbl

100-500 Mbbl

> 1000 Mbbl

500-1000 Mbbl

OWCstrong

weak

OWC

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Geology

CONCLUSIONS

• 3-D seismic data are a valuable compliment to wireline data in defining the structural setting and distribution of reservoir properties in the South Cowden Grayburg field.

• 3-D data illustrate that the field owes its development to the deposition of a lowstand progradational wedge during the middle San Andres.

• Regional data suggest that such progradational wedges may be common along the margin of the Central Basin platform where they provide the structural underpinnings for reservoir development.

• Simple amplitude extraction provides an excellent image of phih and kh distribution which can be used to guide future field exploitation.