RI 5921 A Method Of Predicting Performance Of Five-Spot Waterfloods In Stratified Reservoirs Using Streamlines ? Introduction And Summary

Many contributions to methods of forecasting the performance of waterfloods of a five-spot pattern have been made by investigators. In most of these forecasting methods, a previously selected sweep efficiency is used, and other simplifying assumptions are employed to obtain the objective. In this paper the calculated oil recoveries from several five-spot single- and multiple-layer stratified reservoirs were made with a minimum of assumptions, and because of the techniques used, no previously selected sweep efficiency was required. As a result, the accuracy of the forecast is increased. Permeability curves and continuously changing saturation gradients are used in every section of the pattern. By means of a potentiometric model, the flood pattern is divided into channels, the centers of which are the streamlines. The channels are divided into cells. As flood water enters, the permeability and saturation of each cell change with time. In this study the production from multiple-sand layers of different absolute permeability but with the same relative permeability-saturation relations are combined. The results are shown for a single- and 10-layer reservoir with a permeability variation of 0.60. The oil rate, water-oil ratio, and recovery are shown as functions of time for a 2- and 20-centipoise oil starting in primary phase and after fill-up.