Abstract: Third Bone Spring Sandstone Play: Warwink, West Field, Ward County, Texas

MONTGOMERY, SCOTT L., Petroleum Consultant, Seattle WA

Recent exploration for oil reserves in the Third Bone Spring Sandstone (lower Leonard) has achieved considerable success in the Warwink area, Delaware Basin. A well drilled by Parker and Parsley, Inc. in late 1996 (1 University 18-34) and completed at 720 bbls/d established Warwink, West Field, which has undergone aggressive development. As of October 1997, some 18 wells had been drilled in the new field, with only one dry hole. IPs ranged from 300 - 750 bbl/day and per-well reserves from 275,000 - 500,000 bbls. Current plans include the drilling of an additional 20-30 wells.

The Warwink area is located near the juncture of Ward, Winkler, and Loving counties (Texas), along the structurally complex boundary between the Delaware Basin and Central Basin Platform (CBP). Discovered in 1976, the field produces from dolomite zones in the Wolfcamp and from the Third Bone Spring Sand. Warwink, South, about 1.5 miles east of the new discovery area has produced over 11.5 MMbbls and 15.0 Bcf gas from 51 wells (avg. 225 Mbbl + 300 MMcf per well). Early mapping misidentified the lower Third Bone Spring as "Wolfcamp" and predicted little or no potential west of Warwink, South Recent reinterpretation based on well information, seismic data, and regional sand deposition patterns revealed that excellent sand development and related oil potential in the Warwink, West area. Reservoir sandstones in Warwink, West are very fine to fine grained submarine channel and levee/overbank deposits. Higher energy channel facies are the better reservoirs, due to larger grain size and lower clay content. Two sandstone zones exist (Warwink sand zone and Red Hills sand zone), representing separate submarine fan systems. Porosities and permeabilities within these zones range from 5 - 18% and 0.1 - 5.5 md, respectively. Net pay averages 25 ft. Entrapment is related to updip pinchout of porous facies. Reservoirs exist at 11,400 - 11,550 ft depth and are significantly overpressured.

Isopach data and facies trends indicate local sediment supply was from the northeast, with the CBP acting as source area. Studies of the Brushy Canyon Formation (Delaware Mountain Group) indicate that this was also true during the Guadalupian. Fault-related structures may have been involved in directing sediment supply to the lower slope and basin and in producing bathymetric irregularity controlling fan development. Regional mapping of sand trends suggests good exploration potential in the Third Bone Spring to the west and north of Warwink.

AAPG Search and Discovery Article #90936©1998 AAPG Southwest Section Meeting, Wichita Falls, Texas