热采水平井出砂段套管变形及屈曲风险分析  

Analysis on Casing Deformation and Buckling Risk in Sand Production Section of Thermal Recovery Horizontal Wells

作　　者：肖遥 李进 徐涛[1,2] 袁伟伟 张启龙[1,2] Xiao Yao;Li Jin;Xu Tao;Yuan Weiwei;Zhang Qiong(Tianjin Branch of CNOOC(China)Co.,Ltd.;State Key Laboratory of Offshore Oil Exploitation)

机构地区：[1]中海石油(中国)有限公司天津分公司 [2]海洋石油高效开发国家重点实验室

出　　处：《石油机械》2024年第1期130-137,共8页China Petroleum Machinery

基　　金：中海石油(中国)有限公司科技项目“渤海油田3000万t持续稳产关键技术研究”之子课题“稠油规模化热采有效开发技术”(CNOOC-KJ-135 ZDXM 36 TJ04TJ)。

摘　　要：针对储层出砂对热采井套管变形及稳定性影响的问题,开展了高温蒸汽对稠油储层岩石性质的影响试验;结合传热及热-固耦合理论,建立二维套管-水泥环-地层和三维套管屈曲模型,分析了注热过程中储层出砂对套管变形及屈曲的作用机理,并对比了不同出砂程度对套管变形和屈曲的影响规律。分析结果表明:储层出砂时,套管同时受热应力及周向非均匀地应力作用而产生内壁屈服,随着出砂区域增大,塑性变形逐渐增大;当出砂加剧导致地层亏空时,出砂段套管受储层岩石支撑作用减弱,注热形成的轴向热应力存在导致套管屈曲的风险;注入蒸汽温度为350℃条件下,地层亏空段小于3 m时套管没有屈曲风险;地层亏空段为4 m时,注热过程中套管轴向力达到临界屈曲载荷4 876.9 kN,对应临界屈曲温度为304.9℃,存在屈曲风险,且随着地层亏空段长度的增加,出砂段套管发生屈曲的临界载荷和对应温度均明显降低,屈曲风险加剧。研究结果可为热采井防砂设计及套管选型提供理论指导。Considering the impact of sand production from reservoir on casing deformation and stability in thermal recovery wells,a test was conducted to investigate how high temperature steam affects the rock properties of heavy oil reservoirs.Combined with heat transfer and heat-solid coupling theories,2D casing-cement sheath-forma-tion and 3D casing buckling models were built to analyze the active mechanism of sand production from reservoirs on the casing deformation and buckling during heat injection process,and the influences of different sand produc-tion severities on casing deformation and buckling were compared.The results show that in case of sand production from reservoir,the casing is subjected to both thermal stress and circumferential nonuniform ground stress,resulting in inner wall yielding.As the sand production expands,the plastic deformation gradually increases.When the sand production aggravates to cause formation voidage,the casing in the sand production section is less supported by the reservoir rocks,and there is a risk for the axial thermal stress resulted from heat injection to cause casing buckling.Given the steam injection temperature of 350℃,when the formation voidage section length is less than 3 m,there is a risk of casing buckling;when the formation voidage section length is 4 m,the axial force of casing reaches a critical buckling load(4876.9 kN)in the heat injection process,corresponding to a critical buckling temperature of 304.9℃,so that there is a risk of casing buckling,and as the formation voidage section length in-creases,the critical load and corresponding temperature for the casing in the sand production section to buckle sig-nificantly decrease,exacerbating the risk of buckling.The research results provide theoretical guidance for sand control and casing selection of thermal recovery wells.

关 键 词：热采水平井 出砂 套管变形 屈曲 有限元 

分 类 号：TE257[石油与天然气工程—油气井工程]