Depositional environment of A. W. P. (Olmos) field, McMullen County, Texas
A.W.P. (Olmos) field, located 3.5 mi east of Tilden, in McMullen County, Texas, has been extended 1000 ft downdip or 6 mi south. Gas production has been established from the Olmos sand (upper Campanian) at depths as great as 11,200 ft. The step-out production has established a 2000-ft productive column. Biostratigraphic and lithologic data from cuttings in a downdip well, the Little Oil and Gas 1-A Huff, indicate the Olmos was deposited at an upper-bathyal depth of approximately 1500 ft. The reservoir in the downdip wells consists of four distinct porous members that are correlative with four phases of progradation of a delta front represented by the thinner sequence of beds in the reservoir of the updip wells. Gross sand thicknesses range from 15 to 50 ft in the updip part of the field and from 50 to 100 ft in the downdip extension. The permeability of the reservoir decreases gradationally from 1 md updip to 0.01 md downdip, owing to an increase in clay content in the sediments deposited basinward. Several wells drilled southwest and northeast of A.W.P. field, on strike with production, have tested the theory that the Olmos was deposited as a bar sand resulting from strong longshore currents reworking deltaic sediments.
- OSTI ID:
- 5864108
- Report Number(s):
- CONF-8710198-
- Journal Information:
- AAPG (Am. Assoc. Pet. Geol.) Bull.; (United States), Vol. 71:9; Conference: Gulf-Coast Association of the Geological Society and Gulf-Coast Section SEPM meeting, San Antonio, TX, USA, 28 Oct 1987
- Country of Publication:
- United States
- Language:
- English
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