低渗透油藏强化CO_(2)/水交替注入驱油效果实验研究  

Experimental study on the effect of enhanced CO_(2)/water alternate flooding in low permeability reservoir

作　　者：汤瑞佳 陈龙龙 江绍静 王蓓蕾 谢旭强 TANG Ruijia;CHEN Longlong;JIANG Shaojing;WANG Beilei;XIE Xuqiang(Research Institute of Shaanxi Yanchang Petroleum(Group)Co.,Ltd.,Xi’an 710065,China;CO_(2)Sequestration and Enhanced Oil Recovery Key Laboratory of Shaanxi Province,Xi’an 710065,China)

机构地区：[1]陕西延长石油(集团)有限责任公司研究院,西安710065 [2]陕西省二氧化碳封存与提高采收率重点实验室,西安710065

出　　处：《非常规油气》2024年第4期70-78,共9页Unconventional Oil & Gas

基　　金：国家重点研发计划项目“CO_(2)驱油技术及地质封存安全监测”(2018YFB0605500);陕西省重点研发计划项目“低渗透油藏气驱分级封窜体系研发与性能评价”(2023YBGY311)。

摘　　要：为了强化低渗透油藏CO_(2)/水交替注入(WAG)驱油效果,针对CO_(2)黏性指进问题,提出了锥形WAG驱和活性水WAG驱2种强化驱油效果的方式。通过非均质岩心驱替实验,对比分析了锥形水气比(5∶1~1∶1和1∶1~1∶5)与等比例(1∶1)注入时采出程度变化情况;基于泡沫性能和界面活性评价结果,优选了强化WAG驱用表面活性剂,通过非均质岩心驱替实验评价了活性水强化WAG效果。结果表明:采用锥形WAG驱替时采出程度高于等比例水气比驱替。优选了具有良好起泡性能和低界面张力的L1表面活性剂,L1表面活性剂浓度为0.5%时,泡沫强度达到中等强度,油水界面张力降至2.91×10^(-2) mN/m;L1表面活性剂浓度为0.4%时,高渗层采出程度提高了26.82%,以提高洗油效率作用为主;L1表面活性剂浓度为0.6%时,低渗层采出程度提高了21.48%,以泡沫调驱作用为主。该研究成果为实现低渗透油藏CO_(2)驱油高效开发有指导意义。In order to enhance the effect of CO_(2)/water alternating injection(WAG)displacement in low permeability reservoirs,two methods of cone WAG displacement and active WAG displacement were proposed to solve the problem of CO_(2)viscous fingering.Through heterogeneous core displacement experiment,the change of recovery degree under conical water-gas ratio(5∶1~1∶1 and 1∶1~1∶5)and equal ratio(1∶1)injection is compared and analyzed.Based on the evaluation results of foam properties and interfacial activity,WAG enhanced surfactants were selected and WAG enhanced with active water was evaluated by heterogeneous core displacement experiment.The results show that the recovery degree of cone WAG displacement is higher than that of water gas displacement with equal proportion.L1 surfactant with good foaming performance and low interfacial tension was selected.When the concentration of L1 is 0.5%,the foam strength reaches medium strength and the oil-water interfacial tension decreases to 2.91×10^(-2) mN/m.When the concentration of L1 is 0.4%,the recovery degree of the high permeability layer is increased by 26.82%,mainly to improve the oil washing efficiency.When the concentration of L1 is 0.6%,the recovery degree of the low permeability layer is increased by 21.48%,and the main effect is foam regulation and displacement.The research results have guiding significance for realizing efficient development of CO_(2)flooding in low permeability reservoirs.

关 键 词：低渗透油藏 渗透率级差 CO_(2)/水交替 活性水 泡沫 采出程度 

分 类 号：TE341[石油与天然气工程—油气田开发工程]