基于应变软化模型的地下储气库井筒水泥环完整性研究  

Integrity Analysis of the Cement Sheath in Wellbore of Underground Gas Storage Based on Strain Softening Model

作　　者：冯膑辉 姜婷婷[2] 尚修瑞 张建华[2] FENG Binhui;JIANG Tingting;SHANG Xiurui;ZHANG Jianhua(School of Safety Science and Emergency Management,Wuhan University of Technology,Wuhan 430070,China;School of Resources and Environmental Engineering,Wuhan University of Technology,Wuhan 430070,China)

机构地区：[1]武汉理工大学安全科学与应急管理学院,湖北武汉430070 [2]武汉理工大学资源与环境工程学院,湖北武汉430070

出　　处：《安全与环境工程》2023年第5期66-75,共10页Safety and Environmental Engineering

基　　金：国家自然科学基金项目(51804236)。

摘　　要：地下储气库井筒水泥环完整性失效会导致储气库井筒出现环空带压问题。针对此问题,建立考虑水泥环强度演化特征的应变软化本构模型,运用FLAC~(3D)软件对地下储气库井筒注采天然气循环作业过程进行数值模拟研究,并对采用不同本构模型模拟计算得到的水泥环位移变化和应力分布情况进行了分析。结果表明:(1)建立的水泥环应变软化模型能够反映水泥环的主要力学性质;(2)在经历30次注采循环作业后,采用水泥环应变软化本构模型模拟计算得到的水泥环最大剪应变增量比采用莫尔-库仑本构模型的计算值大31.27%,并且考虑水泥环强度演化特征时,应力集中区域位于水泥环内侧,此时固井界面可能会产生微环隙,导致井筒水泥环完整性降低。该研究结果可为地下储气库井筒稳定性研究提供参考。The failure of cement ring integrity in underground gas storage wellbore will lead to the annular band pressure problem in gas storage wellbore.To solve this problem,this paper establishes a strain-sof-tening constitutive model considering the strength evolution characteristics of cement ring.The research u-ses FLACSD software to conduct numerical simulation research on the gas injection and production cycle op-eration in the wellbore of underground gas storage,and analyzes the displacement change and stress distri-bution of cement ring calculated by different constitutive models.The results are as follows:OThe strain softening model of the cement ring can reflect its main mechanical properties;@After 30 injection and pro-duction cycles,the maximum shear strain increment of the cement ring calculated by using the cement ring strain softening constitutive model is 31.27%larger than that calculated by using the Mohr-Coulomb con-stitutive model.Moreover,considering the strength evolution characteristics of the cement ring,the stress concentration area of the wellbore cement ring is located in the inner side of the cement ring,and micro-an-nular gaps may occur at the cementing interface,and as a result,wellbore cement ring integrity decreases.The research results can provide reference for the research of wellbore stability of underground gas stor-age.

关 键 词：地下储气库 井筒 水泥环完整性 应变软化模型 数值模拟 

分 类 号：X937[环境科学与工程—安全科学] TE822[石油与天然气工程—油气储运工程]