AAPG Annual Convention and Exhibition

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Onshore San Joaquin Basin and Temblor Range, California: New Insights Into the Structural Framework of a Complex and Mature Fold and Thrust Belt.


Aera (Shell/Exxon JV) is currently executing a conventional exploration campaign for remaining prospectivity in the Temblor fold and thrust belt at the western edge of the San Joaquin Basin, central California. This basin is an extremely mature hydrocarbon province, producing for more than a century from thousands of wells. Extensive new 3D seismic acquisition and processing efforts by Aera have resulted in significant uplift in the imaging of the fold-thrust belt. In spite of these advances, imaging of the deep structure of the fold and thrust belt remains challenging. In this talk, we will present a new and comprehensive structural framework that has been developed in support of the exploration campaign. Abundant well data, detailed surface geological maps, and seismic data have been integrated into a series of kinematically constrained cross-sections through the areas of interest. These sections allow us to describe the complex structural geometries and evolution of the basin, which involved an initial phase of normal faulting, followed and completely overprinted by a presently ongoing contractional phase of deformation. The latter is well expressed in the seismic data by folding at multiple scales, ranging from east-directed passive roof basement wedging to thrusting and folding above multiple shallower detachments identified throughout the stratigraphic section. The former is recorded in well data as abrupt thickness changes between areas of gentle thickness gradients and little folding, which is interpreted to reflect syndepositional extensional deformation.