超深水平井套管通过能力分析及安全性评价  

Casing Pass-through Capacity Analysis and Safety Evaluation for Ultra-deep Horizontal Wells

作　　者：杨卫星 赫英状 庹钰恒 张强 练章华 路飞飞[1,2] 李斐[1,2] Yang Weixing;He Yingzhuang;Tuo Yuheng;Zhang Qiang;Lian Zhanghua;Lu Feifei;Li Fei(Research Institute of Petroleum Engineering,Sinopec Northwest Oilfield Company;Key Laboratory of Enhanced Recovery for Fracture-Cave Oil Reservoir,Sinopec;State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation,Southwest Petroleum University)

机构地区：[1]中国石化西北油田分公司石油工程技术研究院 [2]中国石化缝洞型油藏提高采收率重点实验室 [3]西南石油大学油气藏地质及开发工程国家重点实验室

出　　处：《石油机械》2022年第4期139-145,共7页China Petroleum Machinery

基　　金：中国石化重点科技项目“顺北一区5号断裂带提质提速钻完井技术研究”(P20002)。

摘　　要：在超深水平井中,当井眼曲率过大时,套管下入到弯曲井段会由于弯曲应力过高而无法下入或发生受损甚至破坏。针对超深水平井套管下入难题,开展了套管下入极限井眼曲率分析及套管安全性评价。在几何法、解析法的基础上结合有限元法,建立了考虑套管弯曲及带刚性井下工具的套管下入极限井眼曲率模型,研究了弯曲应力对套管强度的影响,并建立了弯曲井段套管压裂时受力分析有限元模型。现场应用结果表明:随着井眼扩大率的增大,极限井眼曲率逐渐增大;随着工具长度的增大,极限井眼曲率逐渐降低;弯曲应力对套管强度有一定影响,高钢级套管抗内压和抗外挤强度受井眼曲率影响较小;利用有限元方法计算了压裂过程中套管应力及安全系数,当井眼曲率及井筒内压较高的情况下,P110套管的安全系数低于1.5,而TP140V套管的安全系数高于1.5。提出的研究计算方法可为超深水平井套管选型及套管优化设计提供依据。In ultra-deep horizontal wells, when wellbore curvature is too large, casing will be unable to run or be damaged and even destroyed due to high bending stress. To address this problem, ultimate wellbore curvature was analyzed and casing safety was evaluated. Based on the geometric method and analytical method, together with the finite element method, the mathematical model of ultimate wellbore curvature was established, which considers casing bending and rigid downhole tools. The influence of bending stress on casing strength was studied, and the finite element model of casing stress analysis during fracturing in curved section was established. The results of field application show that: with the increase of wellbore expansion rate, the ultimate wellbore curvature increases gradually;with the increase of tool length, the ultimate wellbore curvature decreases gradually;bending stress has a certain effect on casing strength, while the burst strength and collapse strength of casing with high steel grade are less affected by wellbore curvature;and the calculation of casing stress and safety factor during fracturing by using the finite element method reveals that the safety factor of P110 casing is lower than 1.5, while the safety factor of TP140 V casing is higher than 1.5, under the conditions of high wellbore curvature and wellbore pressure. The method proposed in this paper can provide a basis for selection and optimization design of casing used in ultra-deep horizontal wells.

关 键 词：超深水平井 通过能力 极限井眼曲率 弯曲应力 安全性评价 

分 类 号：TE243[石油与天然气工程—油气井工程]