Fundamentals of Relative Permeability: Experimental and Theoretical Considerations

Abstract

ABSTRACT Studies investigating the validity of the conventional description of two phase immiscible flow are reported. Laboratory techniques for relative permeability determination have been applied in well controlled experimental conditions to strongly wetting systems. The tests enable a definite description of drainage and imbibition displacement processes. Concurrently a numerical model, based on the conventional macroscopic flow equations was developed to simulate the dynamic displacement tests. The purpose was threefold; 1) To study the concept of relative permeability 2) To simulate the physical processes occurring during unsteady state displacement tests 3) To use the model to assist in the provision of laboratory data more relevant to reservoir simulation. The results show the relative permeability concept is valid for drainage displacement. For imbibition processes the concept is not strictly valid and the macroscopic flow equations are limited in their ability to describe the physical process. Consequently the relevance of laboratory data derived using this conventional theoretical framework is limited and its applicability to the reservoir will depend upon the selection of the appropriate tests. Guidelines as to the selection of the laboratory tests suitable for the different occasions are given and illustrated with a small number of field cases.