Comparison of Two Reservoir Characterization Workflows for Estimating 3D Shale Distribution from Seismic Data

Shale content estimate from seismic data is a key result in the context of HC study in clastic environment. It provides meaningful information concerning reservoir and seal quality. Shale volume (Vsh) can be estimated at well from neutron-porosity, density, or gamma ray logs. The most common way to obtain 3D Vsh is first to derive elastic parameter volumes, related to reservoir properties, from seismic inversion results, next followed by a reservoir characterization workflow. This output bring valuable constraint for geological model building. In this study, two workflows are proposed: a supervised technique using discriminant analysis, and a new mapping method using a response surface. The two techniques have been applied on a dataset composed of well data (Vsh), in addition to S-impedance and density cubes from a PS elastic inversion. Here we show that the Vsh cubes resulting from the two workflows globally show similar trends at large scale, with a good fit with Vsh log at well location, which allows to validate the new workflow; nevertheless, the mapping technique enables to retrieve more detailed and continuous features. As a consequence, the latter Vsh cube will bring additional valuable information for G&G study, such as constrain for geological model building.