环空压力对高温高压井固井二界面接触应力变化的影响  

Effect of Annulus Pressure on Change of Contact Stress at the Two Interfaces of Cementing in High Temperature and High Pressure Wells

作　　者：黄鹏[1] 杨焕强[1] 黄志强[1] 曲路路 吴江 HUANG Peng;YANG Huanqiang;HUANG Zhiqiang;QU Lulu;WU Jiang(College of Petroleum Engineering,Yangtze University,Wuhan 430100,China;CNOOC China Limited,Zhanjiang Branch,Zhanjiang 524000,China)

机构地区：[1]长江大学石油工程学院 [2]中海石油(中国)有限公司湛江分公司

出　　处：《钻采工艺》2020年第5期34-37,I0003,共5页Drilling & Production Technology

基　　金：中海油重点攻关项目“莺琼盆地高温高压钻完井液、固井工艺研究与应用”(编号:CNOOC-KJ 135 ZDXM 24 LTD ZJ 02)。

摘　　要：针对高温高压井水泥浆固化过程中环空压力变化可能引起水泥环密封失效的问题基于全尺寸高温高压水泥环应力传递实验装置,根据厚壁圆筒理论提出了一种测量井下高温、高压条件下水泥环二界面接触应力的实验方法,开展了不同环空压力养护和不同环空压力变化对固井二界面接触应力的影响实验。实验结果表明:其他条件不变在养护时间168 h,随着养护时环空压力越大,最终水泥浆凝固后固井二界面的接触应力越大,最大为21 MPa;针对五组养护好的试件环空压力从12 MPa卸载,随着环空压力卸载的越多水泥环两界面的接触应力就越大,当环空压力从12 MPa直接降到0 MPa时,水泥环第一界面处接触应力达到最大22.7 MPa,水泥环第二界面处接触应力达到最大21.84 MPa,此时水泥环两界面处径向应力也都达到了最大。该研究结果可以现场指导用多大的环空压力对注水泥固井过程中来的油井水泥环进行养护,以及开发后期要避免环空压力的较大的变化引起水泥环密封失效问题。In order to solve the problem that the change of annulus pressure during cement slurry curing in high temperature and high pressure wells may cause the failure of cement sheath seal,based on the developed high temperature and high pressure cement sheath stress transfer experimental device,and according to the thick-wall cylinder theory,an experimental method is proposed to simulate the stress transfer during cement sheath curing under high temperature and high pressure conditions underground. The effects of different annulus pressure curing and different annulus pressure changes on cementing interfaces contact stress were studied. The experimental results show that when the other conditions are not changed and the curing time is 168 h,the greater the annulus pressure is,the greater the contact stress is at two interfaces after the final cement slurry solidifies,the maximum is 21 MPa. For five groups of cured specimens,the annulus pressure is unloaded from 12 MPa. The more the annulus pressure is unloaded,the greater the contact stress of two interfaces of cementing is. The maximum contact stress at the first interface of cement sheath is 22. 7 mpa when the annulus pressure is dropped from 12 MPa to 0 MPa,and the maximum contact stress at the second interface of cement sheath is 21. 84 mpa. At this time,the radial stress at the two interfaces of cement sheath reaches the maximum. The research results can be used to guide how much annulus pressure is used to cure oil well cement sheath in the process of cement injection and well cementing,and avoid the failure of cement annulus seal caused by the large change of annulus pressure in the later stage of development.

关 键 词：高温高压 环空压力 应力传递 接触应力 密封完整性 固井二界面 

分 类 号：TE256[石油与天然气工程—油气井工程]