Reexamination of Late Jurassic Reef Building in the East Texas Basin; a Maturing Gas Play

E. M. Norwood¹ and L. Brinton^2
1Clayton Williams Energy, Inc., Midland, TX
²Geological Consultant, Denver, CO

A depositional model for Late Jurassic reef building in the East Texas Basin was developed for Marathon Oil Company before drilling the MOC Poth #1 in 1993. This outstanding gas well discovery, drilled in a ‘pinnacle’ reef, kicked off a new gas play in an extensively explored basin. The original model was reexamined, integrating information from new wells drilled by other operators. After reevaluation of deposition models, the authors discuss several settings for reef growth during Upper Jurassic, upper Gilmer Limestone through lower Bossier Formations. Uniquely generated paleogeographicmaps underscore the importance of sediment traps in promoting coral reef growth. Development of these thick microbial bound reefal buildups are positioned near the western margin of the East Texas Basin.

In 1998 Clayton Williams Energy reinvigorated and expanded the Jurassic Reef play by stepping out 35 miles southwest to drill a successful reef wildcat. Limits of the play have yet to be defined.

AAPG Search and Discovery Article #90905©2001 AAPG Southwest Section Meeting, Dallas, Texas