基于非均匀载荷的注采井套管损坏机理及抗挤套管校核方法  

Casing Damage Mechanism and Casing Design Method of Injection Production Wells Based on Non-uniform Load

作　　者：周波 毛蕴才 汪海阁 刘明涛[3] 宋学义[3] 杨书港[3] ZHOU Bo;MAO Yuncai;WANG Haige;LIU Mingtao;SONG Xueyi;YANG Shugang(CNPC Engineering and Technology Research Institute Co.,Ltd.,Beijing 102206,China;PetroChina Exploration&Production Company,Beijing 100007,China;Drilling&Production Technology Research Institute of Liaohe Oilfield Company,Panjin,Liaoning 124010,China)

机构地区：[1]中国石油集团工程技术研究院有限公司 [2]中国石油勘探与生产分公司 [3]中国石油辽河油田分公司钻采工艺研究院

出　　处：《钻采工艺》2021年第2期9-12,共4页Drilling & Production Technology

基　　金：国家自然科学基金“深层高温高压油气井安全高效钻完井基础研究”(编号:U1562212);国家科技重大专项子课题“深井超深井井筒安全钻井技术与装备”(编号:2016ZX05020-003);中国石油天然气股份有限公司重大科技专项子课题“钻采工程配套关键技术研究与应用”(编号:2017E-1605)。

摘　　要：注采井网套管损坏是油田井筒完整性管理面临的主要难题之一,注采地层套管载荷影响因素复杂,常规基于均匀载荷的套管校核方法不能有效满足全生命周期井筒完整性要求。采用有限元方法模拟了注采过程地层压力、有效应力及位移场特征及变化规律,揭示了目标区块套管损坏机理;建立了注采井网套管外挤载荷计算模型,提出了基于非均匀载荷影响的套管校核方法。研究表明,注采过程受砂泥岩孔渗差异影响,砂岩与泥岩界面产生有效应力差,泥岩地层吸水水化塑变导致套管载荷非均匀性增大,同时砂泥岩交界面产生较大的位移变形,诱发砂泥岩界面处套管挤压变形或剪切破坏。考虑非均匀载荷因素,当套管载荷非均匀系数小于0.9时,套管等效抗外挤安全系数小于1,套管抗挤强度不能满足实际工况需求。综上研究表明,注采井套管设计时应充分考虑非均匀载荷的影响,基于非均匀载荷的套管设计方法可满足全生命周期套管完整性需求,对其他油田注采井套管设计具有指导借鉴意义。Casing damage in injection production pattern is one of the main problems in the management of wellbore integrity.The influence factors of casing load in injection production formation are complex.Conventional casing check method based on uniform load can not effectively meet the requirements of wellbore integrity in the whole life cycle.The characteristics of formation pressure,effective stress and displacement field in the injection production process are simulated with the finite element method,and the mechanism of casing damage in the target area is revealed.The calculation model of casing extrusion load in injection production well pattern is established,and the casing check method based on the influence of nonuniform load is proposed.The results show that the injection production process is affected by the difference of porosity and permeability of sandstone and mudstone,the effective stress occurring at the interface between sandstone and mudstone is poor,the non-uniformity of casing load increases due to the water absorption,hydration and plastic deformation of mudstone formation,and the larger displacement deformation occurs at the interface of sandstone and mudstone,which leads to the extrusion deformation or shear failure of casing at the interface of sandstone and mudstone.Considering the non-uniform load factor,when the non-uniform load factor of the casing is less than 0.9,the equivalent anti extrusion safety factor of the casing is less than 1,and the anti extrusion strength of the casing cannot meet the actual working conditions.In conclusion,the study shows that the influence of non-uniform load should be fully considered in the casing design of injection production wells.The casing design method based on non-uniform load can meet the requirements of casing integrity in the whole life cycle,which has guiding significance for the casing design of injection production wells in other oilfields.

关 键 词：套管变形 泥岩水化 非均匀载荷 套管校核方法 注水开发 

分 类 号：TE931.2[石油与天然气工程—石油机械设备]