A novel approach to modeling unstable EOR displacements. Quarterly report, April 1993--June 1993

Abstract

This research is aimed at developing a methodology for predicting the performance of unstable displacements in heterogeneous reservoirs. A performance prediction approach that combines numerical modeling with laboratory imaging experiments is being developed. Flow visualization experiments are being performed on laboratory corefloods using X-ray Computed Tomography (CT) and other imaging technologies to map the in situ fluid saturations in time and space. A systematic procedure is being developed to replicate the experimental image data with high-resolution numerical models of the displacements. The well-tuned models will then be used to scale the results of the laboratory coreflood experiments to heterogeneous reservoirs in order to predict the performance of unstable displacements in such reservoirs. In this report, we examine the problem of hydrodynamic instability in miscible displacements. We present the mathematical model for unstable first-contact miscible displacements. The mathematical model is nondimensionalized to derive the dimensionless similarity scaling groups for unstable displacements. Although the mathematical model is not integrated in this report, the dimensionless form of the model reveals the similarity groups that control the displacement performance. CT images of two unstable, first-contact miscible displacements are presented to demonstrate the effects of some of the similarity groups on the displacement performance.