油气藏评价与开发 ›› 2026, Vol. 16 ›› Issue (1): 96-106.doi: 10.13809/j.cnki.cn32-1825/te.2024523

• 方法理论 • 上一篇    下一篇

东海A区块CCS井固井水泥环应力状态与完整性研究

郝锋(), 杜帅, 杨雪峰, 汪珂欣, 高东亮, 黄达   

  1. 中国石化上海海洋油气分公司,上海 200120
  • 收稿日期:2024-11-08 发布日期:2026-01-06 出版日期:2026-01-26
  • 作者简介:郝锋(1995—),硕士研究生,工程师,主要从事钻完井技术研发工作。地址:上海市浦东新区商城路1225号,邮政编码:200120。E-mail:haof.shhy@sinopec.com

Study on stress state and integrity of cement sheath in well cementing of CCS pilot well in block A, East China Sea

HAO Feng(), DU Shuai, YANG Xuefeng, WANG Kexin, GAO Dongliang, HUANG Da   

  1. Sinopec Shanghai Offshore Oil & Gas Company, Shanghai 200120, China
  • Received:2024-11-08 Online:2026-01-06 Published:2026-01-26

摘要:

东海A区块浅层CO2地质封存面临着水平地应力差异大、循环应力影响显著等问题,然而现有水泥环完整性模型未有效建立非均匀地应力场与残余应变耦合作用机制,难以有效评估东海A区块浅层低压储层固井水泥环密封失效行为。因此,针对高地应力差的东海A区块CCS先导试验井在间歇性循环加载-卸载工况下的水泥环性能设计及完整性评价问题,在考虑非均匀地应力与水泥环残余应变影响情况下,结合水泥环剪切破坏和拉伸破坏安全系数评价准则,建立套管-水泥环-地层应力计算模型,基于东海A区块CCS先导试验井地质工程参数开展了水泥环力学应力分析与完整性评价,并开展了地应力差、残余应变及水泥环弹性模量等影响因素分析。研究结果表明:沿最小水平地应力方向的套管-水泥环胶结界面是水泥环发生拉伸破坏及剪切破坏的薄弱点;当井口注入压力增加时,水泥环剪切破坏安全系数呈指数式增大而拉伸破坏安全系数呈线性增大,水泥环更倾向于先发生塑性剪切破坏;地应力差有助于提升水泥环破坏安全系数余量,而水泥环残余应变的增加会造成水泥环破坏安全系数增大,水泥环剪切破坏安全系数随弹性模量的增大先增加后减小,因此,须建立注入压力动态调控机制并优化循环加载路径以抑制残余应变累积效应;为降低在水泥环高弹性模量条件下面临的残余应变值高累积风险,避免水泥环弹性模量在较低的水平条件下面临的剪切破坏安全系数余量较低的问题,在工程实践中需结合注入压力工况确定弹性模量阈值,确保在降低应力集中效应的同时避开剪切破坏安全系数的局部极值区域。

关键词: 碳封存, 固井, 水泥环, 应力, 安全系数, 完整性评价

Abstract:

The shallow CO2 geological storage in block A of the East China Sea faces challenges such as large difference in horizontal in-situ stress and significant influence of cyclic stress. However, existing cement sheath integrity models have not effectively established the coupling mechanism between non-uniform in-situ stress field and residual strain, making it difficult to effectively evaluate the sealing failure behavior of cement sheath in shallow low-pressure reservoirs of block A of the East China Sea. Therefore, aiming at the performance design and integrity evaluation of cement sheath under intermittent cyclic loading-unloading conditions of CCS pilot test well in block A of East China Sea with high in-situ stress difference, and considering the influence of non-uniform in-situ stress and residual strain of cement sheath, a casing-cement sheath-formation stress calculation model was established based on the evaluation criteria of shear failure and tensile failure safety factors of the cement sheath. Using the geological engineering parameters of CCS pilot test well in block A of East China Sea, mechanical stress analysis and integrity evaluation of cement sheath were conducted, and influencing factors such as in-situ stress difference, residual strain, and elastic modulus of cement sheath were analyzed. The results showed that the casing-cement bonding interface along the direction of minimum horizontal in-situ stress was the weak point for tensile failure and shear failure of cement sheath. When the wellhead injection pressure increased, the shear failure safety factor of cement sheath increased exponentially while the tensile failure safety factor increased linearly, and the cement sheath tended to undergo plastic shear failure first. In addition, the in-situ stress difference helped increase the margin of cement sheath failure safety factor, while the increase of cement sheath residual strain caused the increase of cement sheath failure safety factor. The shear failure safety factor of cement sheath first increased and then decreased with the increase of elastic modulus. Therefore, it is necessary to establish a dynamic control mechanism of injection pressure and optimize the cyclic loading path to suppress the cumulative effects of residual strain. To reduce the high cumulative risk of residual strain under conditions of high elastic modulus of cement, and to avoid the problem of low shear failure safety factor margin under relatively low elastic modulus conditions, it is necessary to determine the threshold of elastic modulus according to the injection pressure conditions in engineering practice, ensuring that the stress concentration effects are reduced while avoiding the local extreme value region of the shear failure safety factor.

Key words: carbon storage, well cementing, cement sheath, stress, safety factor, integrity evaluation

中图分类号: 

  • TE52