摘要
页岩气井常采用多级分段压裂技术,环空带压问题将严重影响其长期稳定安全高效开发,井筒水泥环力学状态及水泥环界面承载能力是保证井筒长期密封性能的关键。水泥环界面滤饼层作为井筒最为薄弱区,其力学性能直接关系到水泥环界面承载能力。当前直接测量固井二界面滤饼层力学性能非常困难,构建了滤饼力学性能测试评价方法,开展了界面滤饼力学性能影响规律分析。研究结果表明,钻井液滤饼物相主要包括重晶石、有机土、碳酸钙,滤饼颗粒粒径主要集中在60~80μm,滤饼孔隙度主要集中在10%~20%,滤饼渗透率主要集中在0.05~0.15mD。滤失压差增加、有机土含量增加、滤饼孔隙度降低、滤饼含水率降低均一定程度有助于提高水泥环界面滤饼力学性能。研究成果对于认识井筒水泥环界面载荷分布,优化现场固井施工工艺方案奠定了重要的理论技术支撑。
Shale gas wells are generally fractured with multi-stage fracturing technology,sustained annular pressure will seriously affect their long-term,stable,safe and efficient development.The mechanical state of the borehole cement sheath and the pressure bearing capacity of the interface between the borehole wall and the cement sheath are the key to the long-term sealing of the borehole.The mechanical state of the interface between the filter cake and the cement sheath,which is the weakest part of the borehole,is directly related to the bearing capacity of the interface.Presently it is quite difficult to directly measure the mechanical properties of the filter cake bonded with the cement sheath.In this study,a method of testing the mechanical properties of filter cakes was developed,and the effects on the mechanical properties of the interfacial filter cakes was analyzed.The study shows that the phase of the filter cakes is mainly composed of barite,organophilic clay and calcium carbonate,the sizes of the particles in the filter cakes mainly range from 60μm to 80μm,the porosity of the filter cakes mainly range from 10%to 20%,and the permeability of the filter cakes mainly range from 0.05–0.15 mD.Several factors,such as increase in filtration pressure,increase in organophilic clay content,decrease in filter cake porosity as well as decrease in water content of filter cake,all to some extent help enhance the mechanical properties of the filter cakes bonded with cement sheaths.The results of the study have laid an important theoretical and technical foundation for understanding the load distribution on the interfaces of the cement sheath and for optimizing field well cementing technique scheme.
作者
刘健
宋伟涛
李进
李早元
刘遥瑶
周勇
毛久熊
LIU Jian;SONG Weitao;LI Jin;Li Zaoyuan;LIU Yaoyao;ZHOU Yong;MAO Jiuxiong(School of Petroleum and Natural Gas Engineering,SouthWest Petroleum University,Chengdu,Sichuan 610500;CCDC Downhole Operation Company,Chengdu,Sichuan 610052)
出处
《钻井液与完井液》
北大核心
2025年第5期646-655,共10页
Drilling Fluid & Completion Fluid
基金
国家自然科学基金项目“固井水泥环界面密封损伤机理与改善机制研究”(52274010)
中国石油青年科技专项“川渝高压气井水泥环全生命周期密封失效机理及控制机制研究”(2024DQ03072)
西南石油大学课外开放实验校级重点项目“固井水泥环界面滤饼力学性能及失效机理研究”(2022KSZ01015)。
关键词
页岩气
固井
界面
滤饼
力学性能
Shale gas
Well cementing
Interface
Filter cake
Mechanical property
作者简介
第一作者:刘健,博士,高级实验师,现在主要从事油气井固井与完井方面研究。E-mail:swpiljian@126.com。
