低渗透油藏提高原油采收率的实验研究——以松辽盆地北部芳48断块为例

通过气驱细管实验,在地层条件下测定了大庆油田芳48断块在二氧化碳、氮和天然气驱下原油采收率与压力的关系,由此确定了原油与二氧化碳、氮和天然气的最小混相压力(MMP)。结果表明,芳48断块原油与二氧化碳的最小混相压力为29 MPa,与天然气的最小混相压力为40 MPa,在最高实验压力(44 MPa)下氮没有达到混相。芳48断块气驱开发,在低于地层破裂压力(31 MPa)下,二氧化碳驱可以达到混相驱替,天然气和氮只能是非混相驱。非混相驱时,同样条件下,二氧化碳驱采收率最高,其次为天然气驱,氮驱最低。 

EXPERIMENTAL STUDY TO IMPROVE CRUDE OIL RECOVETY EFFICIENCY IN LOW PERMEABILITY RESERVOIRS——TAKING THE FANG48 BLOCK IN THE NORTH OF THE SONGLIAO BASIN AS AN EXAMPLE

Taking the Fang48 Block in the Daqing Oil Field as an example,it is studied the relationship between crude oil recovery efficiency and pressure when displaced by CO2,N2 and natural gas respectively through slim tube experiment.The minimum miscible pressures(MMP) of CO2,N2,natural gas and crude oil are measured.In the Fang48 Block,the MMP of CO2 is 29 MPa and that of natural gas is 40 MPa.N2 is not miscible from crude oil at the highest experiment pressure(44 MPa).Gas injection has been carried out in the Fang48 Block.Below the formation fracture pressure(31 MPa),CO2 is miscible while natural gas and N2 are not.When immiscible,the recovery efficiency with CO2 displacing is the highest,natural gas the second and N2 the lowest under the same condition.