海上砂岩油藏注自生 CO_(2)体系实验及提高采收率机理  

In⁃situ CO_(2) generation system injection experiment and EOR mechanism for offshore sandstone reservoirs

作　　者：郑玉飞[1,2] 李翔 刘文辉[1,2] 冯轩 宫汝祥[1,2] 王硕 ZHENG Yufei;LI Xiang;LIU Wenhui;FENG Xuan;GONG Ruxiang;WANG Shuo(Production Optimization Business Division of China Oilfield Service Limited,Tianjin 300459,China;State Key Laboratory of Offshore Oil Exploitation,Tianjin 300459,China)

机构地区：[1]中海油田服务股份有限公司油田生产事业部,天津300459 [2]海洋石油高效开发国家重点实验室,天津300459

出　　处：《大庆石油地质与开发》2023年第4期113-121,共9页Petroleum Geology & Oilfield Development in Daqing

基　　金：中海油田服务股份有限公司科技项目“‘N+1’轮层内生成CO_(2)调驱效果优化研究与应用”(YSB19YF019);中海油田服务股份有限公司科技项目“海上陆相砂岩油藏均衡驱油技术研究与应用”(YSB20YF001)。

摘　　要：针对自生CO_(2)技术增产功能多元化、提高采收率机理认识不清的问题,综合利用理化性能评价、岩心驱替及结构表征实验,通过研究体系配方、界面张力、原油黏度、提高采收率效果及岩心孔喉结构的变化,明确了自生CO_(2)技术的主要增产机理。实验结果表明:自生CO_(2)体系中最佳的生气剂与释气剂物质的量浓度比为1∶2,最佳体系质量分数为21.5%,此时的CO_(2)生气效率接近最大值。自生CO_(2)体系在均质和非均质岩心中均具有良好的驱替效率,注入自生CO_(2)体系提高原油采收率(EOR)的机理主要包括:①体系中的生气剂(碱性)可以降低原油与体系间的界面张力(IFT);②在地层中产生的CO_(2)会使原油膨胀、降低原油黏度;③生气剂与释气剂反应放热可溶解有机物并提高采收率,CO_(2)生成过程和清除堵塞引起的压力波动也有助于改变驱油路径、提高采收率。研究成果为自生CO_(2)的技术优化和矿场实践提供了依据。Facing the problem of unclear mechanism of enhanced oil recovery due to diversified stimulation functions of in‑situ CO_(2)generation technology,the main stimulation mechanisms are determined comprehensively by physico‑chemical properties evaluation,core displacement and structural characterization experiments,and by study on system formula,interfacial tension,oil viscosity,enhanced recovery effect and changes of core pore throats structure.The results show that the optimum amount‑of‑substance concentration ratio of gas‑generating agent to gas‑releasing agent is 1∶2 and the optimum system mass fraction is 21.5%,with gas generation efficiency close to the maximum value.In‑situ CO_(2)generation system has high displacement efficiency in both homogeneous and heterogeneous cores.The EOR mechanism of in‑situ CO_(2)generation system injection mainly includes:①gas‑generating agent(alkaline)reduces the interfacial tension between oil and system(IFT);②the CO_(2)produced in the formation expands the oil and reduces oil viscosity;③the heat released by reaction of gas‑generating agent and gas‑releasing agent dissolves organic matter and increases recovery.The pressure fluctuations in the process of CO_(2)generation and clogs removing also help changing the displacement path.The research results provide basis for optimization and field application of in‑situ CO_(2)generation technology.

关 键 词：自生CO_(2) EOR 海上油田 机理研究 

分 类 号：TE357.46[石油与天然气工程—油气田开发工程]