Unit Mobility Ratio Displacement Calculations for Pattern Floods in Homogeneous Medium

Abstract

The influence of pattern geometry on assisted oil recovery for a particulardisplacement mechanism is the object of investigation in this paper.The displacement is assumed to be of unit mobility ratio and piston-like.Fluids are assumed incompressible and gravity and capillary effectsare neglected. With these assumptions it is possible to calculateby analytical methods the quantities of interest to the reservoirengineer for a great variety of patterns. Specifically, this paperpresents (1) very briefly, the methods and mathematical derivationsrequired to obtain the results of engineering concern, and (2) typicalresults in the form of graphs or formulae that can be used readilywithout prior study of the methods.Results of this work provide checks for solutions obtained from programmednumerical techniques. They also reveal the effect of pattern geometryand, even though the assumptions of piston-like displacement andof unit mobility ratio are restrictive, they can nevertheless beused for rather crude but quick, cheap estimates. These estimatescan be refined to account for non-unit mobility ratio and two-phaseflow by correlating analytical results in the case M=1 and the numericalresults for non-Piston, non-unit mobility ratio displacements.In an earlier paper1 it was also shown that from the knowledge ofclosed form solutions for unit mobility ratio, quantities called"scale factors" could be readily calculated, increasing considerablythe flexibility of the numerical techniques. Many new closed formsolutions are given in this paper.