Shale-Drape Modeling for the Geologically Consistent Simulation of Clastic Reservoirs

Abstract

Summary A set of algorithms, called the shale-drape function (SDF), has been developed that incorporates bounding shales (shale drapes) for channels, channel belts (also known as meander belts), lobes and lobe complexes in 3D geologic models used for reservoir simulation. Shale drapes can have a significant impact on the recovery efficiency of clastic reservoirs. Therefore, they need to be modeled when present in significant quantities (in general, more than 50 to 70% in terms of areal coverage). The function incorporates shale drapes into a geologic model with an iterative process that creates shale layers over the entire surface of reservoir objects and then places ellipsoid-shaped holes into shale surfaces until a desired areal coverage is reached. The workflow for application recommends to grid the simulation model along the boundaries of stratigraphic objects, thereby ensuring that the shales can be realistically represented in the fine-scale geomodel and preserved in the post-upscaling simulation model.