长庆低渗透轻质油藏注伴生气提高采收率室内研究

Study on Enhanced Oil Recovery by Associated Gas Flooding in Light Oil Reservoir of Changing Oilfield

在分析长庆三叠系油藏高52区块地质特征和流体性质的基础上,通过室内注伴生气驱油实验和最小混相压力的计算,评价了注伴生气混相驱的可行性,计算得到该区块的最小混相压力为15.11 MPa,大于地层原始压力(13.05 MPa)。因此,该油藏不能进行注伴生气混相开发,但可进行注伴生气的非混相开发。研究了不同注入段塞伴生气对驱油效果的影响和不同注采比下的单井日注气量。结果表明,水驱驱油效率为42.5%,伴生气非混相驱驱油效率为53.3%,提高10.8%。注采比为1.2时,计算得到的注气量为8784 m3/d,井口压力为8.89MPa,该区块日产伴生气可满足注气要求及生产需要。

Based on the analysis of the geological features and fluid properties of the Triassic reservoir in Gao 52,the feasibility of associated gas miscible flooding was evaluated by the flooding experiment and the calculation of minimum miscibility pressure.The minimum miscibility pressure calculated was of 15.11 MPa,which was greater than the initial formation pressure（13.05 MPa）.Therefore,the reservoir could be developed by the associated gas immiscible oil displacement rather than by the miscibility of associated gas.The oil displacement effects of different associated gas slug and the single-well gas injection volume in different injection-production ratio were studied.The experiment results showed that oil displacement efficiency of water flooding was of 42.5% and that of associated gas flooding was of 53.3%,increasing by 10.8%.The gas injection volume and the wellhead pressure of injection well calculated were of 8784 m3/d and 8.89 MPa,respectively,which could satisfy the field application in the injection-production ratio of 1.2.