Three-Dimensional Modeling of Sedimentation and Subsurface Fluid Flow Applied to the Woodbine Progradational System of Southeast Texas

Abstract

An inherent problem of conventional basin modeling is that resolution of space and time is relatively low and simulation results often lack the resolution required to define individual reservoirs. A procedure is proposed by which the known or interpreted stratigraphy is modeled through a three-dimensional deterministic sedimentation simulator (SEDSIM), yielding a more detailed and consistent lithologic distribution. Subsequent postdepositional processes are then applied to the simulated synthetic stratigraphy. Simulated processes include subsidence affected by differential compaction, loading of the lithosphere, and vertical tectonic movement, as well as pore fluid expulsion and hydrocarbon migration. This procedure is particularly well suited for studying reservoirs and for understanding stratigraphic traps. As an example, the simulation model is applied to the Upper Cretaceous Woodbine progradational system of southeast Texas (Polk and Tyler Counties). The experiment simulates progradational wedges over the ancient Buda shelf platform. Burial of the Woodbine by transgressive Eagleford shales and more than 10,000 ft of carbonate and clastic sediments is then modeled as the overburden affects the petrophysical properties of the Woodbine. Results of simulation experiments suggest that conventional cross-sectional interpretation may overestimate the true three-dimensional continuity of individual sand bodies within this shale-rich sequence. Consequences for pore pressure evolution andmore » hydrocarbon generation and migration are modeled and presented.« less