TUNCAY, KAGAN¹, JULIE GOLDING², KENNETH R. SUNDBERG², and PETER J. ORTOLEVA^1
1Laboratory for Computational Geodynamics, Indiana University, Bloomington, IN
²Phillips Petroleum Company, Bartlesville, OK

Abstract: Three Dimensional Modeling of Coupled Salt Diapirism and Rock Deformation: Reservoir Implications

Salt migration and deformation is strongly coupled with the mechanical properties of neighboring formations, evolution of fluid pressure, sedimentation history, and basin subsidence and compression. The strong feedback mechanisms require the simultaneous solution of reaction, transport and mechanical (RTM) equations of mass, energy, and momentum conservation. The RTM processes that are accounted for in this study include multi-phase flow, nonlinear large strain incremental stress rheology, heat flow, petroleum generation, and diagenesis.

In this study, we present results from three-dimensional simulations with multiple shale and sandstone layers below and above the salt body. The importance of the rheologic properties of the sediment was illustrated in our previous two-dimensional studies where we analyzed a thick salt layer underlying an evolving homogeneous sediment layer. Simulations show that: 1- the sediment layers below the salt layer affect the salt migration as much as the layers above it; 2-the salt movement results in a complex network of fractures in the surrounding sediments; 3- these fractures affect the fluid pressure and therefore rheology of surrounding rocks, creating a strong feedback between fracturing, stresses in the surrounding lithologies, and salt migration.

The implications of these effects on the morphology and timing of salt diapirism and its influence on the surrounding reservoirs are discussed.

AAPG Search and Discovery Article #90928©1999 AAPG Annual Convention, San Antonio, Texas