Stochastic reservoir description: a methodology

Abstract Stochastic log interpretation methods are shown to provide more detailed information regarding the geology encountered in a complex formation than can be obtained by conventional interpretation methods. The next stage is to combine these data with qualitative data from other sources than wireline logs to provide information about the ‘rock types’ present. Such rock type definition provides the link between descriptive geological data and the likely hydrodynamic model of interest to reservoir engineers. The final stage in the reservoir description process is to relate the vertical sequence, observed and described in the well bore, to the distribution of the rock types in three dimensions within the reservoir body. This paper presents the methodologies behind each of these three stages in building a more complete reservoir description, and demonstrates their application on actual data from a producing field.