STUDY ON TIME-VARYING LAW OF SEEPAGE IN HIGH WATER-CUT RESERVOIR IN ORDOS BASIN,CHINA

摘要

After the water drive oilfield enters high watercut stage,the reservoir permeability and oil-water phase permeability curve will change greatly due to the long-term water erosion.Traditional numerical simulation software can not accurately simulate this dynamic process.In order to stabilize oil and control water in high water-cut oilfield,and improve oil and gas recovery efficiency,the variation law and mechanism of reservoir parameters must be cleared.In order to achieve the goal of enhancing oil recovery,the dynamic geological model which accords with the actual underground conditions should be established.In this paper,a set of time-varying simulation technology and framework is presented,which can fully consider the real-time variation of various seepage parameters.This new simulation technique has been applied to an unconsolidated sandstone reservoir with high permeability in China.According to the time-varying law of seepage flow in this block,the residual oil distribution and the prediction of final recovery factor are studied under the time-varying condition.The results show that the time-varying model has higher water flooding efficiency and higher predicted ultimate recovery than conventional numerical simulation.The time-varying numerical simulation technique developed in this study can provide a basis for the evaluation of remaining oil and tapping potential of oilfield.It is of great significance for the development and prediction of water drive reservoirs in the later stage.