The early Paleozoic structures and its influence on the Permian strata, Midland Basin: Insights from multi-attribute seismic analysis

摘要

The Permian Basin is one of the most important petroleum-producing regions in the United States. The structural history of the Permian Basin is extremely complex. Most of the structural traps in the Permian Basin are associated with the strike-slip fault system, which presented challenges for past structural interpretation completed primarily using well log and 2D seismic data. We utilized a 3D seismic survey, a part of the Midland Basin and eastern margin of the Central Basin Platform (CBP), to identify the Early Paleozoic structural elements to study its influence on the HC production from the Permian strata. We computed volumetric seismic attributes including, coherence which can identify faults with a significant amount of throw, along with curvature which can detect flexure and folds. We also used, recently developed aberrancy attribute, which illuminates subtle faults and flexures. We observed several strong lineations on seismic attributes extracted along the Woodford surface. Lineations have three different trends. Trend 1 lineations are drag folds associated with the Andrews shear zone (ASZ). Trend 2 lineations, which show a left-lateral strike-slip motion, are R' Riedel Shear, are oriented N 65 degrees W truncating against the CBP. The trend 2 lineations continue upward to the shallower surfaces, as well as they are parallel to the surface lineations identified on the satellite images, which indicates the continued movement of the pre-existing faults. The trend 3 lineations, which show a right-lateral strike-slip motion, are R Riedel Shear and align with the ASZ. The formation micro image (FMI) shows the fracture orientations in trend 2 and trend 3 directions. The aberrancy lineation anomalies are indicative of highly fractured areas; wells drilled in these areas display lower oil-water ratio, as well as a higher amount of production, which may be due to the increase in permeability due to the fractures.