Jurassic Beach: A depositional facies model for smackover stratigraphic traps in the Ark-La-Tex
- TBS Exco, Inc., Houston, TX (United States)
- Reservoirs, Inc., Houston, TX (United States)
State Line field, Union County, Arkansas, produces oil from a five-well stratigraphic trap at 8,900 ft. Conventional cores were cut in all wells. Core studies show that the trapping porosity pinch-out is a facies change from lower foreshore to ooid beach. Sedimentation occurred along a high-energy coastline. Thus, the depositional setting at State Line field differs from the commonly accepted {open_quotes}oolite bar{close_quotes} model used for many other fields in the trend. Four facies were delineated: (1) siliciclastic lagoon (Buckner Formation), (2) ooid beach, (3) oncoid-ooid lower foreshore, and (4) patch reef. Intergranular porosity is facies selective, found mainly in the poorly sorted lower foreshore facies. Cross-stratification and the absence of lime mud indicate high-energy conditions. Porosity and permeability in the lower foreshore facies average 10.9 percent and 496 md, respectively. The ooid beach facies is characterized by well-sorted, crossbedded, and massive ooid grainstones that tend to be extensively calcite cemented. Porosity and permeability values are generally below 2 percent and 1 md, respectively, although they can be higher adjacent to porous lower foreshore strata. The top of the Smackover is a transition from high-energy, sandy ooid beach (grainstone) to low-permeability, lagoonal siliciclastics, which seal the reservoir. Depositional features suggesting tidal channels at the east and west ends of the field support a bench and/or barrier island interpretation. Coral-algal boundstones of the patch reef facies are thin, local, and not of reservoir quality. The value of predicting reservoir trends from cores is shown by a successful 400-ft sidetrack away from a borehole with no reservoir facies or oil shows. A slabbed {open_quotes}piece of the rock{close_quotes} can pay off in Smackover development.
- OSTI ID:
- 45224
- Report Number(s):
- CONF-941065-; TRN: 95:001437-0047
- Resource Relation:
- Conference: 44. annual convention of the Gulf Coast Association of Geological Societies and the 41st annual convention of the Gulf Coast Section of the Society of Economic Paleontologists and Mineralogists, Austin, TX (United States), 5-7 Oct 1994; Other Information: PBD: 1994; Related Information: Is Part Of Gulf Coast Association of Geological Societies: Transactions. Volume 44; Major, R.P. [ed.]; PB: 847 p.
- Country of Publication:
- United States
- Language:
- English
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