Upper Jurassic "reef" play, East Texas basin: An updated overview: Part 1 - Background and outboard trend

This paper is the first part of a two-part update on geologic and geophysic al characterization of gas-productive Upper Jurassic carbonate buildups in the Cotton Valley limestone of the East Texas basin. Continued exploration in this play has yielded important new information on the nature, timing, a nd genesis of the relevant buildup features. This information is crucial to an understanding of existing and future productive trends in the play. Rec ent drilling and discovery have resulted in the identification of two major fairways: (1) an older, outboard (or downdip) trend existing along the dis tally steepened portions of the ramp, at present-day depths of 16,000-17,00 0 ft (4880-5185 m), and (2) a younger, inboard (or updip) trend located alo ng the salt-deformed portion of the Late Jurassic ramp system and lying at depths of 14,100-15,300 ft (4300-4666 m). This paper focuses on the outboar d trend, with discussion of the inboard trend reserved for part 2. Both art icles present core, thin section, and other sample data, as well as seismic information, that together offer the most comprehensive overview of these buildups yet available.