Comparison of Mississippian Barnett Shale, Northern-Central Texas, USA and Silurian Dadas Formation in Southeast Turkey

The organic-rich Barnett Shale is the primary source rock and the main unconventional reservoir in the Fort Worth Basin, Texas. The Early Silurian-Early Devonian Dadas Formation is one of the main source rocks in southeastern Turkey and it is the Turkish equivalent of Silurian hot shales in the Middle East and North Africa. In this study, similarities and differences between the Dadas Formation and the Barnett Shale are presented to indicate the unconventional reservoir potential of the Dadas Formation which covers similar acreage of the Barnett Shale. Main factors that form the basis for comparison are: depositional environment, tectonic setting, thickness, depth, organic geochemical properties and thermal maturity. Both formations have similar depositional environment and they have organic-rich, basal hot shale units indicated by a high gamma-ray log response. Thicknesses of both formations are appropriate to perform horizontal drilling and hydraulic fracturing, however, the Dadas is thicker than the Barnett Shale. Both formations have high Total Organic Carbon (TOC) and Potential Yield (S1 + S2) values. Both formations have gas prone and oil prone regions. However, the gas prone zone of the Barnett is larger. The Dadas Formation is penetrated by only a limited number of wells in comparison to the Barnett Shale. In contrast to the Barnett Shale, which is mainly in the gas zone in the Fort Worth Basin, the Dadas Formation is deeper, and is generally in the oil window.