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

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

摘要: 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。

Abstract: 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.