Pressure analysis and water flooding performance of heterogeneous oil reservoirs.

Abstract

Also, this study presents a modification to the Dykstra-Parson method to predict water flooding performance of multilayered composite reservoirs. The modification takes into account the variations in reservoir properties and dimensions both vertically and horizontally. Two important cases, constant injection rate and constant injection pressure drop were considered. It was found that water flooding performance in multilayered composite linear reservoirs is mainly controlled by the mobility ratio.

This study presents an approximate solution to the problem of unsteady state flow due to production from a single well located in the center of a multiple-layered composite reservoir. Using the technique of superposition in time, expressions for the pressure distribution anywhere in stratified composite reservoirs and the fractional flow rates from each layer of these reservoirs were developed. Both pressure drawdown and buildup behavior of the well bore were considered. Fractional flow rates and drawdown type-curve plots were generated. A type-curve matching technique to determine the reservoir characteristics and dimensions using drawdown pressure data was developed. Due to the fact that two stratified-composite reservoirs with different properties may produce similar pressure buildup curves, Horner and Miller-Dyes-Hutchinson procedures could not be used to predict the reservoir characteristics from pressure buildup.