Optimization Of Enhanced Oil Recovery Method For Low Permeability Reservoir After Water Flooding With Reference To Yanchang Oilfield Typical Reservoirs

China's onshore low permeability oil and gas resources are rich and have an important role in the total reserves.At the same time,the early stage development method of China's low permeability oilfields is waterflooding.Because of the poor physical properties of reservoirs,the overall recovery factor is very low even in the high water cut stage,and the areal and interlayer confict is prominent.Therefore,how to continue to improve oil recovery and maintain stable production after waterflooding in low permeability oilfields is an urgent problem to be solved,which is closely related to the national energy security.This paper aims to study the current development status and existing problems of typical low permeability reservoirs in Yanchang oilfield,so as to analyze the development direction of oil recovery methods for typical reservoirs after waterflooding and make the future development plan.In this paper,the geological characteristics,fluid characteristics,waterflooding development effect and existing problems of typical reservoirs in Yanchang oilfield are analyzed,and numerical simulation models of typical reservoirs are established to predict the future development of waterflooding.For different enhanced oil recovery methods,the influence order of each parameter is analyzed by orthogonal design,and then the optimization of reservoir engineering parameters is made according to the sorting results,and the optimal scheme is obtained.Finally,the optimal schemes of each oil recovery method are compared with each other,and the optimal oil recovery schemes for typical reservoirs in Yanchang oilfield are obtained.