碳封存区块内弃置井泄露机制及控制方法模拟  

Simulation Study of Sealing Integrity in Abandoned Wells Within CO_(2) Sequestration Block

作　　者：王典 李军[1] 刘鹏林 刘献博 连威 路宗羽[3] WANG Dian;LI Jun;LIU Penglin;LIU Xianbo;LIAN Wei;LU Zongyu(College of Petroleum Engineering,China University of Petroleum(Beijing),Beijing 102249;College of Petroleum,China University of Petroleum-Beijing at Karamay,Karamay,Xinjiang 834000;China National Petroleum Corporation Xinjiang Oilfield Branch,Karamay,Xinjiang 834000)

机构地区：[1]中国石油大学(北京)石油工程学院,北京102249 [2]中国石油大学(北京)克拉玛依校区石油学院,新疆克拉玛依834000 [3]中国石油新疆油田公司,新疆克拉玛依834000

出　　处：《钻井液与完井液》2023年第3期384-390,共7页Drilling Fluid & Completion Fluid

基　　金：国家自然科学青年基金项目“页岩气井多级压裂诱发断层滑移量化计算模型与套管变形控制方法研究”(52204018);国家自然科学基金企业创新发展联合基金项目“海相深层高温高压钻完井工程基础理论及控制方法”(U19B6003)。

摘　　要：弃置井筒作为CO_(2)地质封存中的主要泄露途径,其密封完整性直接关乎封存效果。为此,针对弃置井筒泄露问题,基于耦合孔隙压力的Cohesive单元法,建立了三维水泥塞-地层有限元模型,模拟了CO_(2)沿弃置井筒运移过程,分析了水泥浆体系、胶结质量对泄露风险的影响。模拟结果表明:CO_(2)聚积会诱发水泥塞-地层界面微环隙,形成泄露通道,且微环隙倾向于轴向发育;选择高模量、高泊松比、微膨胀性水泥密封井筒时,井筒泄露风险低;微环隙对胶结质量极为敏感,密封井筒时应重点控制胶结质量。研究结果对指导碳封存区块内井筒弃置具有重要意义。As the main leakage pathway in CO_(2) sequestration,the sealing integrity of the abandoned wellbore is directly related to the sequestration effect.To this end,for the abandoned wellbore leakage problem,a three-dimensional finite element model of cement plug-formation is developed based on the cohesive zone method coupled pore pressure.In this paper,we simulated the CO_(2) transport process along the abandoned wellbore and analyzed the influence of cement slurry system and bonding quality on the risk of leakage.The simulation results show that:CO_(2) accumulation induces micro-annulus at the plug-formation interface,forming a leakage channel,and the micro-annulus tends to develop axially;the risk of wellbore leakage is lower when choosing higher modulus,higher Poisson's ratio,and micro-expansion cement to seal the wellbore;the micro-annulus is extremely sensitive to the poor bonding zone,and the control of bonding quality should be focused when sealing the wellbore.The results of this study have important implications for guiding wellbore abandonment within the CO_(2) sequestration block.

关 键 词：CCUS 弃置井 微环隙 数值模拟 井筒完整性 

分 类 号：TE254[石油与天然气工程—油气井工程]