Daniel M. Jarvie¹, Brenda L. Claxton², Floyd "Bo" Henk³, John T. Breyer⁴

(1) Humble Geochemical Services, Humble, TX
(2) Claxton Consulting, Houston, TX
(3) Pachiron Group Consultants, McKinney, Texas, McKinney, TX
(4) Texas Christian University, Ft. Worth, TX

ABSTRACT: Oil and Shale Gas from the Barnett Shale, Ft. Worth Basin, Texas

The widely deposited Devonian-Mississippian shale source rocks have been used as models for hydrocarbon generation by geologists and geochemists for many years, yet these systems are not well understood. The Barnett Shale of the Ft. Worth Basin is similar to the Bakken, Woodford, and Antrim shales and is readily identified as a Type II, marine shale based on its high petroleum potential (ca. 350-1400 BO/AF at low maturity).

Barnett-sourced oil is found in the far western and northern portions of the Ft. Worth Basin in Barnett and other horizons. Gas is derived from both primary cracking of kerogen and oil cracking. Gas production is centered in Wise County, but geochemical mapping suggest opportunities are present across the basin. Production data reveals existing fairways for oil and gas exploration, but detailed compositional yields from kinetic models provide data for high-grading the best prospective sites based on organic facies and maturity mapping.

Retention of hydrocarbons in the Barnett Shale is enhanced by its high carbon content and lithofacies. Fracturing is a key to successful wells and it is assessed to be dependent on several factors including lithofacies, hydrocarbon generation (maturity), and tectonics. Fracture systems can high-graded by a prediction of the best zones from geochemical data including TOC, residual hydrocarbon yields, maturation, and fingerprints completed directly on cuttings or core samples.

AAPG Search and Discovery Article #90906©2001 AAPG Annual Convention, Denver, Colorado