Prediction of Waterflood Behavior in a Stratified System

Abstract

A general model which approximates the effect of cross-flow has been developed to give a practical method for predicting the water/load behavior of a stratified reservoir. The model is based on a modification of Dietz's theory and allows for variations in both the permeability and hydrocarbon pore volume, In the particular cases considered, it is assumed that the permeability can be characterized by a log-normal c1i.stribution and the hydrocarbon pore volume by a normal distribution. A simple graphical method which enables the practicing engineer to predict the behavior of a stratified system is presented The results obtained by the proposed method are compared with those obtained by the Dykstra-Parsons method. As a result of this study the following conclusions have been drawn: (1) The effect of cross-flow in a stratified system can be appreciable, particularly at very favorable or very unfavorable mobility ratios: (2) Under normal conditions, the effect of variations in the hydrocarbon pore volume can be neglected; and (3) The failure to use all of the available permeability data can lead to large errors in the prediction of the behavior of a strati/ ied reservoir.