鄂尔多斯盆地东缘海陆过渡相页岩气层应力敏感实验  

Stress Sensitivity Experiment on Shale Gas Formations in Marine-Continental Transitional Facies in Easten Margin of Ordos Basin

作　　者：李兵 甯冼逸 朱卫平 陈明君[3] 何朋勃[1,2] 康毅力 赖哲涵[3] LI Bing;NING Xianyi;ZHU Weiping;CHEN Mingjun;HE Pengbo;KANG Yili;LAI Zhehan(Institute of Engineering Technology,Petro China Coalbed Methane Company Limited,Xi'an,Shaanxi 710082;China United Coalbed Methane National Engineering Research Center Co.,Ltd.,Beijing 100095;National Key Laboratory of Oil and Gas Reservoir Geology and Exploitation,Southwest Petroleum University,Chengdu,Sichuan 610500)

机构地区：[1]中石油煤层气有限责任公司工程技术研究院,西安710082 [2]中联煤层气国家工程研究中心有限责任公司,北京100095 [3]油气藏地质及开发工程全国重点实验室·西南石油大学,成都610500

出　　处：《钻井液与完井液》2025年第1期30-40,共11页Drilling Fluid & Completion Fluid

基　　金：中国石油天然气股份有限公司“十四五”前瞻性基础性技术攻关项目“海陆过渡相页岩气储层改造技术研究”(2021DJ2004);四川省自然科学基金项目“渗吸压裂液作用下页岩储层纳米限域空间吸附气产出机理研究”(2023NSFSC0939)。

摘　　要：鄂尔多斯盆地东缘海陆过渡相页岩气层致密,孔缝结构复杂,非均质性强,导致应力敏感具有特殊性。选取鄂尔多斯盆地东缘海陆过渡相页岩样品,开展了不同有效应力下的岩心应力敏感实验,明确了储层应力敏感程度,并结合储层岩性和物性特征,揭示了研究区海陆过渡相页岩气层应力敏感机理。研究结果表明,有效应力从3 MPa增大至35 MPa时,人工裂缝、天然裂缝和基块岩心的渗透率分别降低了97.1%、86.8%和50.5%。有效应力卸载过程中,渗透率恢复率分别为21.4%、19.0%和11.6%,表现出显著的应力敏感滞后效应。人工裂缝、天然裂缝和基块页岩的应力敏感系数分别为0.65、0.58和0.19,应力敏感程度分别为强~中等偏强、强~中等偏弱和弱,表明研究区页岩多尺度孔缝结构的应力敏感显著。海陆过渡相页岩矿物组分、裂缝发育程度和孔隙结构是应力敏感损害的主控因素,建议制定保护储层的采气工艺制度,通过控压生产,保障气井高产和稳产。The shale gas formations in the marine-continental transitional facies of the eastern margin of the Ordos Basin are tight gas formations with complex pore and fracture structures as well as high heterogeneity which result in special stress sensitivity of the formations.To understand the degree of the stress sensitivity of the reservoirs,stress sensitivity experiments were performed on cores taken from the marine-continental transitional facies of the eastern margin of the Ordos Basin.The experimental results,combined with the understanding of the lithology and the physical properties of the reservoirs,help reveal the mechanisms of stress sensitivity of the shale gas reservoirs concerned.The studies performed indicate that when the effective stress is increased from 3 MPa to 35 MPa,the permeability of the artificial fractures,the natural fractures and the base core decreases by 97.1%,86.8%and 50,5%,respectively.During unloading of the effective stress,the permeability of the artificial fractures,the natural fractures and the base core is recovered by 21.4%,19.0%and 11.6%,respectively,showing significant stress sensitivity hysteresis effects.The stress sensitivity coefficients of the artificial fractures,the natural fractures and the base core are 0.65,0.58 and 0.19,respectively,and the degrees of stress sensitivity corresponding to these stress sensitivity coefficients are classified as strong-moderate to strong,strong-moderate to weak and weak.The stress sensitivity coefficients show that the multi-scale pore-fracture structure of the shales under research have significant stress sensitivity.The main control factors of formation damage by stress sensitivity include the mineral components,the development of the fractures as well as the pore structure of the shales in the marine-continental transitional facies.It is thus suggested that a reservoir-protective gas production system be developed,and the production of gas be controlled to ensure high production rate and stable production of the gas wells drilled in the

关 键 词：页岩气 海陆过渡相 应力敏感 渗透率 裂缝 鄂尔多斯盆地东缘 

分 类 号：TE258[石油与天然气工程—油气井工程]