Development of a Coupled Crustal Deformation-Pore Pressure Diffusion Module with Application to Overpressure and Petroleum Systems in the Delaware Basin, west Texas

Gregory Dyer
Department of Geology and Geography, Auburn University, AL 36849,
[email protected]

Many of the world’s important sedimentary basins are located in tectonically active regions. Implications range from the affects deformation has upon petroleum systems and basin-wide fluid migration to the potential for earthquakes to damage wells or production facilities. We developed a new 3D time-dependent pore-pressure diffusion model PFLOW to investigate the response of pore fluids to transient dynamic strains. The flexibility of this model allows for multiphase modules to interface with coupled crustal deformation and fluid flow software, providing a key asset for quantitatively determining the contribution of sediment compaction, hydrocarbon generation, or tectonic faulting on overpressure development.

This research models regional fluid flow in the Delaware Basin in conjunction with geochemical analysis and petrophysics data to examine overpressure conditions and its role on hydrocarbon migration. Initial overpressure conditions in the Delaware Basin were created by rapid sedimentation during the late Permian. Overpressure is still presently detected despite a lack of significant sedimentation over the past 250 m.y. Preliminary geochemical analyses of crude oil samples suggest a strong genetic correlation between oil source rocks in the eastern Delaware Basin and reservoir rocks along the margins of the basin. Preliminary numerical modeling suggests that continued hydrocarbon generation within shale source beds are most likely the reason for continued overpressure maintenance and furthermore, providing evidence that such large pressure gradients could drive long-distance hydrocarbon migration from deep source beds eastwards into the east Delaware Basin and westwards to the Central Basin Platform.

AAPG Search and Discovery Article #90094 © 2009 AAPG Foundation Grants in Aid