填充介质对非均匀应力下双层套管所受应力的影响  

Influence of filling medium on the stress on double-layer casing under nonuniform stress

作　　者：张俊成 李忠慧[1,2] 张艳英 胡棚杰 杨恺 朱亮[1,2] ZHANG Juncheng;LI Zhonghui;ZHANG Yanying;HU Pengjie;YANG Kai;ZHU Liang(Lost Circulation Prevention and Control Laboratory,National Engineering Laboratory for Oil and Gas Drilling Technology,School of Petroleum Engineering of Yangtze University,Wuhan 430100,Hubei,China;Key Laboratory of Hubei Province for Oil and Gas Drilling and Production Engineering,Wuhan 430100,Hubei,China;Engineering and Technology Research Institute,CNPC Bohai Drilling Engineering Company Limited,Tianjin 300457,China;CNOOC China Limited Qinhuangdao 32-6 Operation Company,Tianjin 300459,China)

机构地区：[1]长江大学石油工程学院油气钻井技术国家工程实验室防漏堵漏研究室 [2]油气钻采工程湖北省重点实验室 [3]中海石油(中国)有限公司秦皇岛32-6作业公司 [4]中国石油集团渤海钻探工程技术研究院

出　　处：《石油钻采工艺》2021年第6期744-749,共6页Oil Drilling & Production Technology

摘　　要：采用双层套管是防止盐膏层套管变形和损坏的有效手段,而填充介质是影响双层套管整体力学性能的重要因素。以荆丘地区J45断块沙一段盐膏岩层段套管为研究对象,在确定盐膏岩蠕变本构方程的基础上,应用有限元方法建立了地层-水泥环-外层套管-填充介质-内层套管在非均匀地应力条件下的受载模型,得到内外层套管在不同填充介质厚度、不同填充介质类型条件下的等效应力分布,并进行比较分析。结果表明:增加介质厚度能减弱应力传递效果,但对双层套管整体所受等效应力影响较小;介质类型对套管所受等效应力影响较大,采用机油和天然橡胶介质时内层套管等效应力为使用水泥介质的33.55%和5.87%。基于以上规律,推荐采用正常钢级外层套管+液体介质+低钢级内层套管的双层套管,可以有效降低成本和保障油气生产安全。The double-layer casing is an effective means to prevent casing deformation and failure in salt beds,and the filling medium is an important factor influencing the overall mechanical property of double-layer casing.In this paper,the creep constitutive equation of salt bed was determined by taking the casing in the salt bed of the first Member of Shahejie Formation in Fault Block J45 of Jingqiu area as the research object.Based on this,the loading model of formation-cement sheath-outer casing-filling medium-inner casing under nonuniform in-situ stress was established by means of the finite element method.In addition,the distribution of equivalent stress on inner and outer casings at different filling medium thicknesses and types were figured out and comparatively analyzed.It is indicated that the increase of medium thickness can weaken the stress transmission effect,but has less influence on the equivalent stress on the double-layer casing overall.The medium type has greater influence on the equivalent stress on the casing.The equivalent stress on the inner casing with the medium of machine oil and natural rubber is 33.55%and 5.87%of that with the medium of cement,respectively.According to above mentioned laws,it is recommended to adopt the double-layer casing of normal-grade outer casing+liquid medium+low-grade inner casing,which can reduce the cost effectively and ensure the safety of oil and gas production.

关 键 词：井筒完整性 套管保护 盐膏层 非均匀应力 双层套管 填充介质 有限元模拟 等效应力 

分 类 号：TE256.2[石油与天然气工程—油气井工程]