Mobility Ratio - Its Influence on Injection or Production Histories in Five-Spot Water Flood

Abstract

Abstract Potentiometric model studies of the five-spot water flood to determine the influence of mobility ratio upon injection or production histories are described. The results, suggest a method for the correlation of data from field pilot tests for the estimation of an effective mobility ratio and its effect upon field water floods. The effect of the well spacing-to-well radius ratio upon production histories is presented. A method of accounting for this factor is suggested. The influence of injection (or production) rates and injection and production well pressures upon production histories is shown. The fivespot well pattern was investigated for water-to-oil mobility ratios of 0.1 to infinity. Introduction It has been well established that mobility ratio has an important effect upon flood patterns. It should be equally apparent that injection and production histories must also be influenced by mobility ratio. However, none of the articles referred to above mention the importance of being able to predict the effect of well pressures (or injection rates) during the entire time history of a waterflood operation. A complete description of production histories (the terms "injection" and "production" are synonymous for the steady-state model under consideration) would provide values for well pressures and interface positions at any time for a specified injection rate. Conversely, if the waterflood problem is specified in terms of a constant injection well pressure, then it would be desirable to know the injection rate and interface positions at any time.