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3-D Seismic Attributes Expression of Differential Compaction Related to Karst Collapses in the Barnett Shale, Fort Worth Basin, Texas


Karst-collapse features from the Ellenburger Group in the Permian Basin, West Texas can give rise to increased hydrocarbon production. Previous works have shown how specific filling pattern of karst-collapsed features affect the overlaying layers. Similar models have also been used to describe the karst-collapse filling patterns in the Newark East Field in the Fort Worth Basin in north Texas, where the post-Ellenburger Group deposits are clearly affected by the karst-collapses. However, there are important stratigraphic differences between the Permian and Fort Worth Basins. West of the Newark East Field, in southern Wise County, the Viola and Simpson Formations thin-out and the Barnett Shale lies directly over the top of the highly karsted Ellenburger Group. Hardage (2002) used pressure analysis and production patterns from wells drilled inside two different karst collapses in the Boonsville Field to show how the Ellenburger karst-collapsed features affected the deposition of the Barnett Shale, Atokan and Caddo Formations. In this study we use 3D seismic attributes that characterize the stratigraphy of the internal architecture within the Fort Worth Basin karst-collapse to better understand how these known drilling hazards affect the production patterns. We conduct an intensive exploratory data analysis using 3D seismic attributes including spectral decomposition, reflector curvature, reflector convergence, and prestack inversion identify differential compaction effects in the Barnett Shale due to the increase in accommodation space controlled by the karst collapses at the top of the Ellenburger Group. Finally, we partially correlate these features to production of oil, water and gas.