--> Abstract: Stratigraphic Hierarchy Of Organic Carbon-Rich Siltstones In Deep-Water Facies, Brushy Canyon Formation (Guadalupian), Delaware Basin, Texas, by J. M. Armentrout, K. E. Peters, B. B. Sageman, A. E. Murphy, and M. H. Gardner; #90928 (1999).

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ARMENTROUT, JOHN M.1, and KEN E. PETERS1, BRADLEY B. SAGEMAN2 , ADAM E. MURPHY2 , and MICHAEL H. GARDNER3
1Mobil Exploration and Producing Technical Center, Dallas, TX
2
Northwestern University, Evanston, IL
3
Colorado School of Mines, Golden, Colorado

Abstract: Stratigraphic Hierarchy of Organic Carbon-Rich Siltstones in Deep-Water Facies, Brushy Canyon Formation (Guadalupian), Delaware Basin, Texas

Sequence stratigraphy provides a hierarchical system for organizing and analyzing depositional cyclicity. The distribution of organic carbon within a sequence stratigraphic framework is examined to determine the primary factors controlling total organic carbon content and hydrocarbon yield potential. The studied section includes the Pipeline Shale, Brushy Canyon Formation and the lower Cherry Canyon Formation of the Permian Delaware Mountain Group. These strata represent one 3rd-order, siliciclastic genetic sequence deposited as a deepwater gravity-flow system along a passive margin. Depositional cycles of 4th- and 5th-order scale are identified within a 450 meter thick section. Two-hundred ten samples were collected, one from each slightly brown to black fine-grained bed. Each sample was split and sent for analysis: one split to Northwestern University for analysis using a Fisons NA 1500 elemental analyzer; the second split to the Institut Francais du Petrole for analysis on Rock-Eval 6. Measured values of total organic carbon (TOC) from each lab compare favorably. Patterns of increasing and decreasing Hydrogen Index (HI) and TOC values parallel each other. Enrichment and yield potential increases upward toward the flooding surface capping -each order of cyclicity. Values of TOC and HI increase progressively from 5th-order to 4th-order to 3rd-order cycles. Maximum values of TOC = 4.5% and HI > 300 occur within a three meter thick organic rich interval at the thirdorder flooding surface (genetic top of Brushy Canyon sequence). Preliminary data suggest sediment dilution is the primary control on organic-richness in these relatively proximal basin slope deposits. Additional sections will be studied.

AAPG Search and Discovery Article #90928©1999 AAPG Annual Convention, San Antonio, Texas