Tubb

Low

er C

lear

For

kW

ichi

ta

LOWER CLEAR FORK - WICHITA FACIES AND STRATIGRAPHYKEYSTONE SOUTH CLEAR FORK FIELD, WINKLER COUNTY, TEXASWEST EAST

A A’W

ichi

ta s

eque

nce

W1

Wic

hita

UpperWAporosity(CC)

W1

UpperWA

porosity(CC)

Wic

hita

seq

uenc

e W

2

B/LCF(CC)

W2

LCF

sequ

ence

L2.

1

Low

er C

lear

For

k

T/Main CFporosity

(CC)

LCF

sequ

ence

L2.

2LC

F se

quen

ce L

2.3

Tubb S

sequ

ence

L3

LCF

sequ

ence

L2.

1LC

F se

quen

ce L

2.2

W2

LCF

sequ

ence

L2.

3

W1

STRATIGRAPHY AND FACIES OVERVIEWLOWER CLEAR FORK

EXPLANATIONLower Clear Fork/Tubb Systems Tracts

TST: shallow water silty peritidal; low permeability

TST-early HST: subtidal; more discontinuous porous and permeable facies

Late HST: tidal flat-capped subtidal; most porosityin low permeabilty, continuous cycle tops

Ooid/peloid grain-dominated packstone

Peloid packstone

5

Peloid wackestone-packstoneSkeletal wackestone

Fusulinid/peloid packstone7 Fusulinid wackestone

Mudstone

Siltstone/sandstone6

Tidal flat1

No core

2

8

4

3

9

Oncolite packstone

Polymict cave fill conglomerateLithoclast breccia

Peloid grain-dominated packstone

Roof crackle breccia

Core Facies

WICHITA

The Lower Clear Fork comprises three high frequency sequences (HFS) thatare part of a major composite (3rd-order) sequence. Each HFS is composed of alower transgressive leg (TST) and an upper highstand leg (HST). TSTs arecharacterized by dominantly subtidal cycles that contain facies that display goodporosity and permeability but limited lateral continuity. HSTs are characterized bytidal flat-capped subtidal cycles. The porosity in these cycles is concentrated in thetidal flat caps which, although continuous, generally have low permeability.

Regionally, the Wichita facies comprises mud-dominated, restricted peritidalto tidal flat deposits that are locally karsted. Cores from Keystone South are generallyconsistent with this interpretation although they indicate less restricted conditions(more subtidal) than at Fullerton field for example. Based on cores, neither faciesor cycles exhibit much lateral continuity. Wichita porosity and permeability appearto be controlled by mineralogy as much as by facies. Although not marked by afacies change, the change in mineralogy from dolostone to limestone at the W1marker may correspond to a major sequence boundary that has been defined fromregional outcrop and subsurface studies.

Exposed cycle topSubtidal cycle topCorrelation marker

Correlations

Wichita Systems TractsTST-HST: restricted shallow subtidal to peritidal; porousand locally permeable; facies continuity poor.

By S. C. Ruppel, 2006

6900

6950

6900'

70007000'

Keystone Cattle Co. # 422

71007100'

6950'

71507150'

70507050'

0.1

6100

6150

6200

6250

6300

6350

6400

6450

6500

6550

6600

6650

6700

6750.0

Keystone # 431

CGRGAPI0 150

GR_ND_1GAPI0 150

DEPTHFEET

RHOB_1G/CC2 3

NPHI_1V/V0.3 -0.1

DTUS/F70 40

PEF_1B/E0 10

6050

6100

6150

6200

6250

6300

6350

6400

6450

6500

6550

6600

6650

6700

6750

6800

6850

6900

6950

7000

7050

7100

7150

7200

7250

7300

7350

7400

7450

7500.0

Keystone # 415

CGRGAPI0 150

GR_ND_1GAPI0 150

DEPTHFEET

RHOB_1G/CC2 3

NPHI_1V/V0.3 -0.1

DT_1US/F70 40

PEF_1B/E0 10

CGRGAPI0 150

GR_1GAPI0 150

6250

6300

6350

6400

6450

6500

6550

6600

6650

6700

6750

6800

6850

6900

6950

7000

7050

7100

7150

7200

7250

7300

7350

7400

6200.0

DEPTHFEET

RHOB_1G/CC2 3

NPHI_1V/V0.3 -0.1

PEF_1B/E0 10

Keystone # 406

6050

6100

6150

6200

6250

6300

6350

6400

6450

6500

6550

6600

6650

6700

6750

6800

6850

6900

6950

7000

7050

7100

7150

7200

7250

7300

7350

7400

7450

CGRGAPI0 150

GR_ND_1GAPI0 150

5500.0

DEPTHFEET

RHOB_1G/CC2 3

NPHI_1V/V0.3 -0.1

PEF_1B/E0

Keystone # 416

6150

6200

6250

6300

6350

6400

6450

6500

6550

6600

6650

6700

6750

6800

6850

6900

6950

7000

7050

7100

7150

7200

7250

7300

7350

7400.0

CGRGAPI0 150

GR_1GAPI0 150

6000.0

DEPTHFEET

RHOB_1G/CC2 3

NPHI_1V/V0.3 -0.1

US/F

PHI_1V/V0.3 -0.1

PEF_1B/E0 10

Keystone # 409

Keystone Cattle Co. # 409

7000'

7050''

7100'

CGR

GAPI0 150

GR_RES_SHFT_4GAPI0 150 DEPTH

FEET RHOB_SHFT_1

G/CC2 3

NPHI_SHFT_1V/V0.3 -0.1

PEF_1

B/E0 10

Keystone # 422

6100

6150

6200

6250

6300

6350

6400

6450

6500

6550

6600

6650

6700

6750

6800

6850

6900

6950

7000

7050

7100

7150

7200

7250

7300

7350

7400

7450

7500

CGRGAPI0 150

GR_1GAPI0 150

6050

6100

6150

6200

6250

6300

6350

6400

6450

6500

6550

6600

6650

6700

6750

6800

6850

6900

6950

7000

7050

7100

7150

7200

7250

7300

7350

6000.0

7400.0

DEPTHFEET

RHO8_1G/CC2 3

NPHI_1V/V0.3 -0.1

PHI_1V/V0.3 -0.1

PEFZ_1B/E0 10

6430

6440

6450

6460

6470

6480

6490

6500

6510

6520

6530

6540

Keystone # 437

0.1110

Keystone Cattle Co. # 437

6400'

6450'

6500'

6550

CGRGAPI0 150

GR_1GAPI0 150

6050

6100

6150

6200

6250

6300

6350

6400

6450

6500

6550

6600

6650

6700

6750

6800

6850

6900

6950

7000

7050

7100

7150

7200

7250

7300

7350

6000.0

7400.0

DEPTHFEET

RHOZ_1G/CC2 3

NPHI_1V/V0.3 -0.1

PHI_1V/V0.3 -0.1

PEFZ_1B/E0 10

Keystone # 438

Keystone Cattle Co. # 438

6800'

6850'

6900'

6950'

KETCHUM MT.

DOVE CREEK

PAROCHIAL-BADE

HOWARD-GLASSCOCK

VAREL

REVILO

LUCY

DIAMOND -M-

SHARON RIDGE

COLEMAN RANCH, N.

COLEMANRANCH

WESTBROOK, EAST

MIRIAM

P.H.D.

ROCKER -A-

GUINN

POST

WTG

SMYER

ROPES, E.

HARRISFLANAGAN

ROBERTSON, N.RILEY, NORTH

RUSSELL

WASSON 72

OWNBY

PRENTICE

KINGDOM

SUNDOWN LEEPER

WARHORSE

BROWNLOVINGTON

MIDWAYDOUBLE A, SOUTHDOUBLE A

EMPIRE

BUCKEYEVACUUMCORBIN

HAL JAMAR

LEVELLAND

ANTON

ANTON-IRISH

RIDGE

HOOPLE

EDMISSON

KEYSTONE

KEYSTONE, SOUTH

EMPORER

MONAHANS, N.

DOLLARHIDEJUSTIS

FOWLER

TEAGUE

DRINKARD

OIL CENTER

METZ

PENWELL

C-BARMONAHANS

CRAWAR

SAND HILLS

MCKEE

BAYVIEW

SUN VALLEY, N.BROOKLAW

SUN VALLEY

BROWN & THORP

WENTZTIPPETT

BROWN & THORP,EAST

ROBERDEAU, S.

UNION

FULLERTON

SHAFTER LAKE

DEEP ROCK

FUHRMAN SOUTH

NIX, SOUTH

BLOCK 12

MARTIN

TXL

MONUMENT BLOCK A-34

HOBBS

WELTMER

WEIR

SCAGGSHOUSE

BRUMLEYWARREN

PADDOCK

GOLDSMITH

GOLDSMITH, W.

TURNER-GREGORY

EMBAR

JACKSON

DELAWAREBASIN

CENTRALBASIN

PLATFORM

0 25 50 miles

CROSBY

DICKENS

KENT

SCURRY

LYNN

DAWSONGAINES

MITCHELL

GLASSCOCK

ANDREWS

MIDLAND

TOM GREENSTERLING

UPTON

ECTOR

TERRY

BORDEN

GARZA

MARTIN

HALE

LUBBOCKHOCKLEY

LAMB

CHAVES

EDDY

LOVING

REAGAN

CRANE

PECOS

WINKLER

REEVES

COCHRAN

YOAKUM

WARD

IRION

EASTERN SHELF PERMIAN CARBONATE

LEONARDIAN PLATFORM CARBONATE

NORTHERN SHELF PERMIAN CARBONATE

LEA

EA STERN

SHELF

HOWARD

NORTHERN SHELF

MIDLANDBASIN

BLINEBRY

KeystoneSouth

Middle Permian Paleogeography and Leonardian Fields

Lower Clear Fork Structure: Keystone South Field

14

13

12

11

10

9

8

7

4

3

2

127

28

29 30

BLK. B2

A

A'

-3700

-3700

-3700

-3700

-3800

-3800

-3800

-3600

-3700

29

301

CT30

300

259

237

425

255

203

414

439

431251

258

435

125E

138T

432

415440

413

155

441

186

406

147T

416

181

256

412

153

411

234 407

403

149

206

408

183

429

404 427

142T

141T

436150

405

200430

418

252145T

428

156

379 1236

417

151

420

158

2571

220

254

410

188

54419

152

235

298

1

253

102157

303

304

422 437

438

409

B

B’

N

Core

Explanation

50000 ft

Line of sectionA A’

Map supplied by David McMahon

Winkler County, TexasKeystone South Field

Wichita-Albany Structure

(Courtesy of Crownquest)