大庆石油地质与开发2026，Vol.45Issue(3)：83-90,8.DOI:10.19597/J.ISSN.1000-3754.202501030
玛湖油田致密砾岩油藏CO2前置压裂提产机理
CO2 pre-pad fracturing mechanism for production enhancement in Mahu Oilfield tight conglomerate reservoir
摘要
Abstract
Aiming at the problem of low recovery of conventional hydraulic fracturing due to development of com-plex pore structures and high proportion of small pores in tight conglomerate reservoir with"three lows"(low pres-sure coefficient,low oil saturation and low formation saturation pressure difference)characteristics in Mahu Oil-field,the mechanism of CO2 pre-pad fracturing to enhance oil recovery in tight conglomerate is studied systematical-ly in 3 aspects of improving microscopic pore throats producing,enhancing oil mobility and strengthening fractures network stimulation through high-pressure and high-speed core injection,high-temperature and high-pressure me-dia interaction and pseudo-triaxial fracturing simulation experiments.The results show that high-pressure injection of CO2 significantly changes the microscopic pore throat structure,increasing total porosity of core by 7.7%when displacement pressure difference is increased by 6 MPa,and lower limit of pore throat producing is reduced from 0.1 μm to 0.03 μm.High-pressure injection changes wettability of rock to neutral,and significantly reduces interfa-cial tension and adhesion work of oil,effectively improving CO2 molecular adsorption and oil displacement efficien-cy.CO2 has obvious effects on increasing energy and reducing oil viscosity,and has strong solubility to acid-soluble minerals and weakly cemented substances in conglomerate,effectively increasing oil displacement energy of forma-tion,improving reservoir properties and enhancing oil fluidity.CO2 pre-pad can significantly increase complexity of hydraulic fractures network and increase drainage area.The research reveals comprehensive production enhance-ment mechanism of CO2 pre-pad fracturing in tight conglomerate reservoirs,and provides key theoretical foundation for optimization of fracturing process parameters and large-scale promotion of this type of reservoir.关键词
致密砾岩/"三低"油藏/CO2前置压裂/高温高压/微观作用机制Key words
tight conglomerate/"three-lows"reservoir/CO2 pre-pad fracturing/high-temperature and high-pres-sure/micro-action mechanism分类
能源科技引用本文复制引用
王涛,徐文熙,吴世龙,李作阳,刘田,张继卓,李轶,石善志..玛湖油田致密砾岩油藏CO2前置压裂提产机理[J].大庆石油地质与开发,2026,45(3):83-90,8.基金项目
中国石油天然气股份有限公司重大科技专项"砾岩油藏规模增储上产与提高采收率关键技术研究"(2023ZZ24YJ06). （2023ZZ24YJ06）
