Contrasting Styles of Basin Fill and Shelf Margin Stacking, Wolfcampian-Leonardian-Guadalupian Succession, Eastern Margin of Central Basin Platform and Western Midland Basin, Fasken Ranch Area, West Texas

Abstract

Controls on the development and distribution of reservoir quality facies in unconventional systems remains a fundamental research question, one whose answer differs depending on basin setting and age. One area of intense focus for resource play development is the Midland Basin where targets in both Wolfcampian and Leonardian strata are currently driving intense development activity. This study uses an exceptional dataset including 500 sq mi of 3D seismic, more than 13,000 wireline logs, and a growing database of conventional core descriptions out of an available suite of more than 200 cores) to generate a detailed model of shelf-to-basin depositional patterns.

The Fasken Ranch volume covers critical shelf-margin to basin transitions for the complete Permian section. A 400-500 ft thick Hueco platform is interrupted by multiple significant erosional episodes, likely driven by high amplitude, high-frequency eustatic oscillation. Basinal Wolfcamp “shales” show marked vertical and lateral heterogeneity and linking debris vs shale accumulation is a major challenge, but major shedding intervals are likely tied to ravinement following exposure of these 200-300 ft high platforms. The >1000 ft Leonardian 1-6 succession (Abo through lower and upper Clear Fork) and equivalent Spraberry Fm basin fill is initiated by a major backstep relative to the Hueco margin, followed by aggradational stacking and development of a high-relief margin that sheds dilute turbidites and large-scale mass transport deposits. San Andres platforms and their equivalent Cutoff, Brushy Canyon, and Cherry Canyon successions match their Delaware Basin equivalents. However, basinal Grayburg G10 lowstand deposits mark a dramatic phase of forced regressive mixed clastic-carbonate infill of the Basin. Three-dimensional models of the integrated depth-converted seismic, log, and core data allows recognition of distinct styles of basin fill and reservoir facies development.

AAPG Datapages/Search and Discovery Article #90323 ©2018 AAPG Annual Convention and Exhibition, Salt Lake City, Utah, May 20-23, 2018