Use of Connection Constraints for Checking and Enhancing Geological Models

Abstract

Abstract To ensure consistency between geological models and dynamic models, it is necessary to constrain geological models to information coming from dynamic synthesis about permeable pathways between some points in the reservoir. The paper presents a methodology which can be fully implemented using commercial software. It is based on the analysis of connected components calculated on geostatistical simulations in a post-processing phase. The analysis of physical connections in a single lithostratigraphic unit is studied. The use of connected components to QC facies or petrophysical properties simulations is detailed and the impact of simulation parameters (facies proportion, variogram range, etc...) on the presence of permeable pathways in the static model is studied. The generalization to structural geological models is described. In this case, successive lithostratigraphic units can be potentially connected through faults when the fault throw is large enough. A two-steps workflow for conditioning simulations to information about connections between points in difficult cases is presented. The first step is the identification of the realizations matching the connection criteria. The second step consists in choosing additional conditioning data for further simulations ensuring that the wells connection constraints are honored, the model’s statistical properties being preserved. The efficiency of this workflow is discussed. A method for integrating faults and fractures patterns in calculations in complex cases is proposed. Once the stochastic realizations of a geostatistical model honor observed connections between selected points, it is interesting to characterize the connection for improving model QC. Some possible ways of using connected components in advanced models QC are suggested. In the end, some ideas for accounting for connection characteristics in geostatistical simulations are proposed.