Constructing a stratigraphic framework for the Mississippian Barnett Shale: northern and central Fort Worth Basin, Texas

Sediment comprising the gross reservoir (Barnett base-Morrowan top) was first deposited over Paleozoic strata during marine transgression, followed by highstand aggradation and progradation. Chronostratigraphic cross sections illustrate relationships between flooding events and facies belts in the gross reservoir. The reservoir model supports mineralogic trends identified in the gross reservoir that grade from carbonate to silica to clay-rich in a northwest/southeast orientation across the Fort Worth basin. Facies analyses identify organic richness associated with the gross reservoir increases south/southeast away from the Newark East field. Gamma ray response in the Barnett Shale > 100 API units indicates > ~4% vol. TOC, the basal limit accepted for commercial production in unconventional shale reservoirs. High TOC indicates greater porosity and hydrocarbons present in the Barnett Shale. Based on organic richness, mineralogic composition, and geochemical considerations, southeastern Tarrant, northern Johnson, and northwestern Ellis counties contain the best reservoir qualities for gas generation and accumulation.