Study On EOR Of Lukeqin Ultra-deep Heavy Oil By Polymer Flooding

The Lukeqin Triassic reservoir in Xinjiang,China,is a heavy oil reservoir with high temperature and high salinity.The formation conditions are harsh.With the deepening of oilfield development,the reservoir enters into a high water cut period and faces the problem of stable oil and water control in the middle and late stage of development.In addition,the heavy oil reservoir has complex characteristics,such as deep,thin,thick and so on,so it can not be converted to conventional thermal recovery mode.Therefore,a solution to the reservoir conditions is urgently needed.Mainly supported by the following understand:In order to improve the mobility ratio of water drive,a new type of high temperature resistance and high salinity polymer SWP322 has been developed.In this study,the compatibility,viscosity,temperature resistance,salt resistance and shear resistance of the polymer in Lukeqin reservoir are better than that of HPAM.Finally,the formation conditions of Lukeqin reservoir are simulated to test the percolation and oil displacement ability of the new polymer SWP322 under the conditions of high temperature and high salinity.Experiments show that the polymer has a temperature resistance of 100?and a salinity resistance level of 2.0×10~5mg/L.in the process of simulated oil displacement,the displacement efficiency of water flooding is 30.43%,while the flooding efficiency of first polymer flooding and subsequent water flooding is 16.6%higher than that of water flooding;the oil displacement efficiency of double-pipe polymer flooding is 13.19%higher than that of water flooding;the oil displacement efficiency of single tube and double tube flooding system is 16.1%and23.2%higher than that of water flooding,respectively.This study has effectively improved the oil displacement efficiency of Lukeqin ultra-deep high temperature and high salinity heavy oil reservoir.Moreover,SWP322polymer can be directly prepared with formation water,which not only saves clean water(especially in the west),but also does not have the problem of incompatibility with formation water.The matching and perfection of SWP322 polymer system will be an effective way to improve oil recovery through polymer injection in Lukeqin reservoir.