Predicting Salt Tectonic Morphologies and Associated Reservoir Characteristics Using a Basin Evolution/Sedimentation/Geochemical Simulator

Faical Tounsi, Julie Boyd, Changxing Qin, and Peter J. Ortoleva

Salt tectonics coupled to mechanics, chemistry, hydrology and sedimentary processes are integrated into a three dimensional simulator. The simulator describes the evolution of salt and sediment deformation, fluid motion and composition/phase, and temperature in three spatial dimensions over geological time.

Depocenters are shown to arise due to salt withdrawal into diapirs, waves or other features. These centers collect sediments of character that depend on overall depositions and the details of the salt tectonic-induced sediment-water surface topography. The resulting characteristics, geometry and extent of potential reservoirs, even after (and if) salt beds have disappeared through salt tectonics reflect the past history of the overall sedimentary history, thickness of the original salt bed and possible, deeper-lying reactivated faults.

As our model integrates all these effects in three spatial dimensions, the code can be used to develop relations between (remotely determined) salt tectonic feature and the location, geometry and characteristics of associated reservoirs. General roles for such correlations are presented based on a sensitivity study using our simulator. The simulator can be used to model specific areas and examples from the U.S. Gulf Coast will be given.

Our model can also be used for production to predict near borehole salt velocities. As input, the present-day salt morphology is given; the output is file velocity of salt at each point of the salt body.

AAPG Search and Discover Article #91019©1996 AAPG Convention and Exhibition 19-22 May 1996, San Diego, California