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Abstract: Reservoir Characterization in a Modern Exploration and Production Environment

W. Scot Evans

The reservoir characterization process integrates all available rock and fluid data for a given reservoir, and then develops the best possible model from it. The process is dynamic, due to the sporadic addition of new data, and reservoir properties changing with production. The resulting models are used as input to reserves calculations, reservoir simulation, and in support of development decisions.

Reservoir characterization projects can be divided into three phases:

Data Assembly and Local Analysis: All available 'hard' data from each discipline is analyzed and integrated. This cross discipline phase challenges the organizational structures of many companies, and highlights deficiencies in application and database integration.

Extrapolation and Model Building The limited density of available 'hard' data always demands extrapolation (generation of 'soft' data) to achieve complete reservoir coverage. Techniques range from hand contouring, to deterministic computer mapping, and recently to probabilistic geostatistical techniques. Geostatistics qualify 'soft' data with estimations of variance and probability, and allows for the assignment of risk.

Model Visualization and Use To obtain the most value from all the data generated during reservoir characterization, geoscientists and engineers must be able to visualize and analyze the reservoir and it's properties in three-dimensional space. In addition, results must be easily accessible to other applications.

A major consideration in reservoir characterization is whether seismic data is available, and of sufficient resolution to provide reservoir scale information. Examples from producing fields in Southeast New Mexico and the Gulf Coast illustrate issues associated with large multidisciplinary studies, and modern interpretive, analytical, and visualization methods.

AAPG Search and Discovery Article #90956©1995 AAPG International Convention and Exposition Meeting, Nice, France