非均匀载荷下页岩气套管抗挤强度全尺寸试验及新机理  

Full-Scale Test and New Mechanism on Collapsing Strength of Shale Gas Casing Under Nonuniform Load

作　　者：姬丙寅 余夫[2] 罗蒙[2] 孙建安[2] 史交齐 董晓明[2] Ji Bingyin;Yu Fu;Luo Meng;Sun Jian'an;Shi Jiaoqi;Dong Xiaoming(Xi'an Serv Stress Engineering Technology Service Co.,Ltd.;Baoshan Iron and Steel Co.,Ltd.)

机构地区：[1]西安三维应力工程技术有限公司 [2]宝山钢铁股份有限公司

出　　处：《石油机械》2023年第9期148-154,共7页China Petroleum Machinery

基　　金：陕西省重大科技创新专项资金项目计划“石油管材全尺寸评价试验系统产业化”(2018ZKC-119)。

摘　　要：为研究页岩气套管非均匀载荷下抗挤强度及失效机理,采用全尺寸试验方法,开展平面非均匀载荷、弧面非均匀载荷、平面载荷和均匀载荷组合、弧面载荷和均匀载荷组合等4种非均匀载荷情况的试验研究。试验结果表明:非均匀载荷下套管失效机理为套管承载非均匀载荷后,引起的直径变化率发生变化。随着载荷的增大,当直径变化率达到临界状态下,套管发生失效,即达到套管临界承载能力;套管直径变化率与套管抗挤强度近似呈反相关,直径变化率越大,套管的抗挤强度越小。当套管直径变化率小于0.5%时,套管抗挤强度降低不明显,当套管直径变化率≥0.5%时,套管抗挤强度影响显著,套管直径变化率范围为1.0%~2.0%,抗挤性能下降15%~20%。建议页岩气套管可以选择厚壁套管,提高抗径向变形能力,或者基于应变设计理论控制套管径向变形,或者采用弹性介质封固方式以减少外力对套管径向变形的影响,而不是一味追求增加套管的抗挤强度。所得结论对页岩气套管选材或减少页岩气套管失效具有指导作用。In order to study the collapsing strength and failure mechanism of shale gas casing under nonuniform load,the full-scale test method was used to carry out research on four kinds of nonuniform loads:plane nonuniform load,cambered surface nonuniform load,plane load and uniform load combination,and cambered surface and uniform load combination.The test results show that after the casing has borne the nonuniform load,the diameter change rate changes.As the load increases,when the diameter change rate reaches a critical state,casing failure occurs,i.e.,reaching the critical bearing capacity of the casing.The diameter change rate of the casing is approximately inversely correlated with the collapsing strength of the casing.The larger the diameter change rate,the smaller the collapsing strength of the casing is.When the diameter change rate of the casing is less than 0.5%,the decrease in the collapsing strength of the casing is not obvious.When the diameter change rate of the casing is greater than or equal to 0.5%,the effect on the collapsing strength of the casing is obvious.When the diameter change rate of the casing is between 1.0%and 2.0%,the collapsing strength decreases by 15%to 20%.It is proposed to select heavy casing to improve the resistance to radial deformation,or control the radial deformation of the casing based on the strain design theory,or use the elastic medium sealing method to reduce the impact of external forces on the radial deformation of the casing,instead of blindly seeking to increase the collapsing strength of the casing.The conclusions have guiding significance to the selection of shale gas casing materials or the reduction of failure of the shale gas casing.

关 键 词：页岩气套管 非均匀载荷 抗挤强度 全尺寸试验 新机理 

分 类 号：TE931[石油与天然气工程—石油机械设备]