In order to evaluate the oil mobility in the tight sandy conglomerate reservoirs of the Triassic Baikouquan formation in the Mahu sag,the distribution characteristics of movable oil in typical rock samples from Type Ⅰ and Type Ⅱ reservoirs were compared through im-bibition,centrifugation,and huff-n-puff tests.For the low-permeability conglomerate reservoirs in the Mahu sag,the imbibition oil recovery is related to the pore structure of the rock.The higher the proportion of small pores,the better the imbibition effect.After 144 hours of oil displacement by imbibition,the recovery rate can reach 30.9%,but the oil displacement process is slow,with low utilization of large pores.Under reservoir pressure of 40 MPa and reservoir temperature,during three cycles of CO2 huff-n-puff process,the recovery percent of each round increase,with the highest increase observed in the first cycle,reaching an oil exchange ratio of 27%.As the huff-n-puff cycle increas-es,the increment in recovery percent gradually decreases,and the oil exchange ratio of N2 huff-n-puff in the first cycle is 15%.Therefore,CO2 huff-n-puff has the best development effect.
NETL
NSTL
维普
万方数据
