致密油藏CO2驱和水驱分子动力学模拟及微观机理OA北大核心CSTPCD

In order to clarify the micro oil displacement mechanisms of CO2 flooding and water flooding,the CO2 and water oil displace-ment models are established respectively using molecular dynamics simulation method.The variation laws of density of crude oil in hy-drophilic nanopores with displacement time under different displacement conditions were studied,and the migration process of hydrocar-bon molecules in nanopores during oil displacement was analyzed.The research results indicate that as the injection rate increases,the oil displacement efficiency of both oil displacement media increases.During CO2 flooding,when the injection rate is low,the expansion of CO2 plays a major role;As the injection rate increases,displacement gradually plays a dominant role.In the process of water flooding,when the injection rate is low,imbibition plays a major role in hydrophilic nanopores.At this time,the displacement rate of crude oil in small pores is faster than that in large pores;As the injection rate increases,displacement gradually plays a dominant role,and the crude oil in the large pores is rapidly displaced.