地层类型对水泥环的力学作用及影响  

Mechanical action and effect of the stratum types on cement sheath

作　　者：张景富[1] 公海峰 靳建州 徐明 王建成 李勇[2] 黄昭 ZHANG Jingfu;GONG Haifeng;JIN Jianzhou;XU Ming;WANG Jiancheng;LI Yong;HUANG Zhao(Key Laboratory of Enhanced Oil and Gas Recovery,Ministry of Education,Northeast Petroleum University,Daqing,Heilongjiang 163318,China;Cementing Institute,CNPC Engineering Technology R&D Company Limited,Beijing 102206,China)

机构地区：[1]东北石油大学提高油气采收率教育部重点实验室,黑龙江大庆163318 [2]中国石油集团钻井工程技术研究院有限公司固井完井研究所,北京102206

出　　处：《东北石油大学学报》2020年第4期30-39,I0003,共11页Journal of Northeast Petroleum University

基　　金：国家自然科学基金项目(51474074);黑龙江省自然科学基金项目(E201334)。

摘　　要：地层类型制约地应力对固井水泥环的力学作用方式,明确地层类型对水泥环应力和结构完整性的影响特征,是建立井筒完整性保障技术的基础。以蠕变、弹性、刚性地层为研究对象,建立套管—水泥环—地层固结体有限元力学模型,分析地层类型、施工项目等对水泥环界面应力的影响。结果表明:蠕变地层中,地应力增加,界面接触压力增大;弹性、刚性地层中,地应力对界面应力无影响。蠕变、弹性地层中,地层弹性模量对界面应力的影响与地层、应力类型有关;刚性地层中,地层弹性模量对界面应力无影响。弹性地层中,加载时,水泥环易发生周向拉伸破坏,危险部位为窄间隙内界面。套管试压施工时,存在水泥环拉伸破坏的危险,危险井段为井口及深部弹性地层井段;储气库井注气施工时,存在的主要危险为加载过程中弹性地层井段水泥环本体拉裂破坏。The stratum types restrict the mechanic action mode of cementing cement sheath by the crustal stress.Defining the effect characteristics of the stratum types on the stress and structural integrity of cement sheath is basis for developing or establishing wellbore integrity assurance technology.Taking creep,elastic and rigid strata as objects,the finite element mechanics models of the casing-cement sheath-stratum combination body(CCSCB)were established.The influence of formation type,construction project,etc.on the interface stress of cement sheath is analyzed.The results show that,in the creep stratum,the interface contact pressure of cement sheath increase and circumferential stress reduce with the increase of crustal stress.There is no effect of crustal stress on the interface stress in the elastic and rigid stratum.The effect of stratum elastic modulus on the interface stress is related to stratum and stress type in creep and elastic stratum.There is no effect of the elastic modulus on the interface stress in rigid stratum.In elastic stratum,the cement sheath is prone to circumferential tensile failure during loading,and the dangerous position is the inner interface of narrow gap in eccentric annuli.In casing pressure test construction,there is no tearing of cemented interface,but there is risk of cement sheath tensile failure.The dangerous well section is wellhead and deep depth in elastic stratum section.During gas injection construction in gas storage well,the main risks are the tensile rupture of the cement sheath body in the elastic strata well section during loading.

关 键 词：地层类型 地应力 固井 水泥环 胶结界面 接触压力 周向应力 结构完整性 

分 类 号：TE256[石油与天然气工程—油气井工程]