Failure of Stream Tube Methods To Predict Waterflood Performance of an Isolated Inverted Five-Spot at Favorable Mobility Ratios

Abstract

Failure of Stream Tube Methods To Predict Waterflood Performance of an Isolated Inverted Five-Spot at Performance of an Isolated Inverted Five-Spot at Favorable Mobility Ratios Introduction Since their introduction by Higgins and Leighton in 1962, stream-tube methods (STM) have been used by a number of authors to make approximate waterflood and gas flood calculations. The principal justification for the methods is given by Higgins and Leighton, who present excellent agreement between their STM results and the experimental and numerical result of Douglas et al. for a wide range of M values in a repeated five-spot-pattern waterflood. Doyle presents fair to good agreement between STM results and laboratory model results for five-spot and direct line drive well configurations. The basic assumptions of the Higgins-Leighton STM arethat the streamlines are independent of the mobility ratio, andthat Buckley-Leverett theory can be used to calculate the fluid displacement between adjacent streamlines. The first assumption allows the streamlines to be determined from singlephase flow and to be held fixed as the flood progresses. In their original work, Higgins and Leighton used potentiometric model results to determine the potentiometric model results to determine the streamlines. Other authors, including us, have used analytical and numerical methods involving pressure and stream-function solutions. Discussion Fig. 1 presents calculated oil recovery vs displaceable pore volumes injected for an isolated inverted fivespot pore volumes injected for an isolated inverted fivespot pattern for various values of M. pattern for various values of M. JPT P. 151