SEISMIC CHARACTERIZATION OF FINE-GRAINED UPPER CRETACEOUS RESERVOIRS WITHIN THE GREAT PLAINS POLYGONAL FAULT SYSTEM

A 3-D seismic dataset is used to characterize the structural variations in Upper Cretaceous sediments within the Great Plains polygonal fault system (GP PFS). Polygonal fault systems are pervasive arrangements of normal faults and fractures that can form in fine-grained sediments shortly after deposition and without external stresses. An extensive polygonal fault system is hosted within fine-grained Late Cretaceous sediments deposited beneath the Great Plains of the United States and Canada. The fault traces intersect laterally to form coalesced fault traces with polygonal geometries in plan view. The Great Plains PFS has faulted strata throughout Canada and the United States. A 3-D seismic dataset from southwest Saskatchewan will show that Cretaceous sediments within and above the Second White Speckled Shale Formation are extensively faulted. The complex faulting is best imaged with 3-D seismic data designed to image the shallow reservoirs. The talk will present fault throw, strike, and dip measurements using the 3-D seismic data. These measurements can be used to construct a simple model to predict polygonal fault occurance using well control alone within the Great Plains area.