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6900 6950 6900' 7000 7000' Keystone Cattle Co. # 422 7100 7100' 6950' 7150 7150' 7050 7050' 0.1 6100 6150 6200 6250 6300 6350 6400 6450 6500 6550 6600 6650 6700 6750.0 Keystone # 431 CGR GAPI 0 150 GR_ND_1 GAPI 0 150 DEPTH FEET RHOB_1 G/CC 2 3 NPHI_1 V/V 0.3 -0.1 DT US/F 70 40 PEF_1 B/E 0 10 6050 6100 6150 6200 6250 6300 6350 6400 6500 6550 6600 6650 6700 6750 6800 6850 6900 6950 7000 7050 7100 7150 7200 7250 7300 7350 7400 7450 7500.0 Keystone # 415 CGR GAPI 0 150 GR_ND_1 GAPI 0 150 DEPTH FEET RHOB_1 G/CC 2 3 NPHI_1 V/V 0.3 -0.1 DT_1 US/F 70 40 PEF_1 B/E 0 10 CGR GAPI 0 150 GR_1 GAPI 0 150 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 DEPTH FEET RHOB_1 G/CC 2 3 NPHI_1 V/V 0.3 -0.1 PEF_1 B/E 0 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 CGR GAPI 0 150 GR_ND_1 GAPI 0 150 5500.0 DEPTH FEET RHOB_1 G/CC 2 3 NPHI_1 V/V 0.3 -0.1 PEF_1 B/E 0 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 CGR GAPI 0 150 GR_1 GAPI 0 150 6000.0 DEPTH FEET RHOB_1 G/CC 2 3 NPHI_1 V/V 0.3 -0.1 US/F PHI_1 V/V 0.3 -0.1 PEF_1 B/E 0 10 Keystone # 409 Keystone Cattle Co. # 409 7000' 7050'' 7100' CGR GAPI 0 150 GR_1 GAPI 0 150 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 DEPTH FEET RHOZ_1 G/CC 2 3 NPHI_1 V/V 0.3 -0.1 PHI_1 V/V 0.3 -0.1 PEFZ_1 B/E 0 10 Keystone # 438 Keystone Cattle Co. # 438 6800' 6850' 6900' 6950' CGR GAPI 0 150 GR_1 GAPI 0 150 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 DEPTH FEET RHO8_1 G/CC 2 3 NPHI_1 V/V 0.3 -0.1 PHI_1 V/V 0.3 -0.1 PEFZ_1 B/E 0 10 6430 6440 6450 6460 6470 6480 6490 6500 6510 6520 6530 6540 Keystone # 437 0.1 1 10 Keystone Cattle Co. # 437 6400' 6450' 6500' 6550 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 PATTERNS IN MINERALOGY AND POROSITY LOWER CLEAR FORK The lowermost Lower Clear Fork sequence (L2.1) is dominantly composed of limestone whereas the upper two sequences (L2.2, L2.3) are essentially entirely dolostone. Although porosity is developed in both limestone and dolostone in L2.1, highest porosities appear to be associated with dolostone intervals. Dolostone increases in abundance to the west in sequence L2.1 in this cross section; this, combined with data from Section B-B’, suggests that porosity in this sequence is highest in the southwestern part of the field. LOWER CLEAR FORK - WICHITA MINERALOGY KEYSTONE SOUTH CLEAR FORK FIELD, WINKLER COUNTY, TEXAS WEST EAST A A’ WICHITA The Wichita is composed of a lower dolostone-dominated section (W1) and an upper limestone dominated section (W2). Porosity is best developed in dolostones of the lower Wichita; W1 limestones are generally nonporous. Porosity is locally developed in the upper Wichita principally in dolostone intervals. However, some W2 limestones are also locally porous. Low porosity limestone intervals in W1 are relatively continuous and probably act as flow baffles. Wichita sequence W1 Wichita Lower WA porosity (Crownquest) W1 Upper WA porosity (Crownquest) Wichita sequence W2 B/LCF (Crownquest) W2 LCF sequence L2.1 Lower Clear Fork T/Main CF porosity (Crownquest) LCF sequence L2.2 LCF sequence L2.3 Tubb Ssequence L3 LCF sequence L2.1 LCF sequence L2.2 W2 LCF sequence L2.3 W1 TUBB The Tubb is composed of alternating layers of dolostone and siltstone. Siltstone intervals appear to be relatively continuous across the field. Previous studies show that these Tubb silt-rich rocks usually have very low permeability. EXPLANATION Ooid/peloid grain-dominated packstone Peloid packstone 5 Peloid wackestone-packstone Skeletal wackestone Fusulinid/peloid packstone 7 Fusulinid wackestone Mudstone Siltstone/sandstone 6 Tidal flat 1 No core 2 8 4 3 9 Oncolite packstone Polymict cave fill conglomerate Lithoclast breccia Peloid grain-dominated packstone Roof crackle breccia Core Facies Exposed cycle top Subtidal cycle top Correlation marker Correlations Mineralogy Limestone: generally low porosity and permeability Dolostone: generally higher porosity and permeability KETCHUM MT. DOVE CREEK PAROCHIAL-BADE HOWARD-GLASSCOCK VAREL REVILO LUCY DIAMOND -M- SHARON RIDGE COLEMAN RANCH, N. COLEMAN RANCH WESTBROOK, EAST MIRIAM P.H.D. ROCKER -A- GUINN POST WTG SMYER ROPES, E. HARRIS FLANAGAN ROBERTSON, N. RILEY, NORTH RUSSELL WASSON 72 OWNBY PRENTICE KINGDOM SUNDOWN LEEPER WARHORSE BROWN LOVINGTON MIDWAY DOUBLE A, SOUTH DOUBLE A EMPIRE BUCKEYE VACUUM CORBIN HAL JAMAR LEVELLAND ANTON ANTON-IRISH RIDGE HOOPLE EDMISSON KEYSTONE KEYSTONE, SOUTH EMPORER MONAHANS, N. DOLLARHIDE JUSTIS FOWLER TEAGUE DRINKARD OIL CENTER METZ PENWELL C-BAR MONAHANS CRAWAR SAND HILLS MCKEE BAYVIEW SUN VALLEY, N. BROOKLAW SUN VALLEY BROWN & THORP WENTZ TIPPETT 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 SCAGGS HOUSE BRUMLEY WARREN PADDOCK GOLDSMITH GOLDSMITH, W. TURNER- GREGORY EMBAR JACKSON DELAWARE BASIN CENTRAL BASIN PLATFORM 0 25 50 miles CROSBY DICKENS KENT SCURRY LYNN DAWSON GAINES MITCHELL GLASSCOCK ANDREWS MIDLAND TOM GREEN STERLING UPTON ECTOR TERRY BORDEN GARZA MARTIN HALE LUBBOCK HOCKLEY 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 E A S T E R N S H E L F HOWARD N O R T H E R N S H E L F MIDLAND BASIN BLINEBRY Keystone South CGR GAPI 0 150 GR_RES_SHFT_4 GAPI 0 150 DEPTH FEET RHOB_SHFT_1 G/CC 2 3 NPHI_SHFT_1 V/V 0.3 -0.1 PEF_1 B/E 0 10 Keystone # 422 By S. C. Ruppel, 2006 Tubb Lower Clear Fork Wichita Middle Permian Paleogeography and Leonardian Fields 14 13 12 11 10 9 8 7 4 3 2 1 27 28 29 30 BLK. B2 A A' -3700 -3700 -3700 -3700 -3800 -3800 -3800 -3600 -3700 29 301 CT30 300 259 237 425 255 203 414 439 431 251 258 435 125E 138T 432 415 440 413 155 441 186 406 147T 416 181 256 412 153 411 234 407 403 149 206 408 183 429 404 427 142T 141T 436 150 405 200 430 418 252 145T 428 156 379 1 236 417 151 420 158 257 1 220 254 410 188 54 419 152 235 298 1 253 102 157 303 304 422 437 438 409 B B’ Lower Clear Fork Structure: Keystone South Field N Winkler County, Texas Keystone South Field Wichita-Albany Structure (Courtesy of Crownquest) Core Explanation 5000 0 ft Line of section A A’ Map supplied by David McMahon
