深水高温高压气井环空圈闭压力下油管柱安全评价方法  

Safety Evaluation Method for Tubing Strings under Annular Trapping Pressure in Deep Water High Temperature and High Pressure Gas Wells

作　　者：刘书杰 罗鸣 马传华 吴艳辉 唐龙 张智[3] 丁剑 LIU Shu-jie;LUO Ming;MA Chuan-hua;WU Yan-hui;TANG Long;ZHANG Zhi;DING Jian(Hainan Branch,CNOOC(China)Co.Ltd.,Haikou 570100,China;CNOOC EnerTech-Drilling&Production Co.Deepwater Branch,Haikou 570100,China;State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation(Southwest Petroleum University),Chengdu 610500,China)

机构地区：[1]中海油(中国)有限公司海南分公司,海口570100 [2]中海油能源发展股份有限公司工程技术深水钻采技术中心,海口570100 [3]西南石油大学油气藏地质及开发工程国家重点实验室,成都610500

出　　处：《科学技术与工程》2024年第12期4959-4968,共10页Science Technology and Engineering

基　　金：国家自然科学基金(U22A20164,52074234);中海油(中国)有限公司重大科技项目(CNOOC-KJ 135 ZDXM 38 ZJ 05 ZJ)。

摘　　要：深水高温高压气井普遍存在环空带压现象,而深水井通常采用水下井口,使得B、C环空无法进行泄压操作,从而导致井下油管柱承受高环空圈闭压力载荷,同时附加高温、腐蚀多因素耦合影响,使得油管柱存在失效风险。针对深水高温高压气井环空圈闭压力下油管柱安全问题,基于深水井特性,综合考虑热膨胀和鼓胀效应引起的环空温度、环空体积、流体体积以及环空压力变化的动态耦合作用,建立深水高温高压气井圈闭压力预测模型,同时,考虑高环空圈闭压力载荷,附加高温及腐蚀多因素耦合影响,建立深水高温高压气井油管柱安全评价方法,开展了环空圈闭压力多因素影响下油管柱安全评价,并对模型进行了验证。结果表明:考虑环空圈闭压力影响后,环空圈闭压力随服役时间逐渐降低幅度远小于地层压力降低幅度,管柱抗外挤安全系数随服役时间降低幅度增大。同时,管柱内外流体压差随井深增加而逐渐增大,在井底管柱更易发生失效风险;在井筒高温及腐蚀耦合影响下,管柱抗内压、抗外挤及抗拉安全系数均呈现出不同程度的降低,特别井底段管柱受苛刻高温及腐蚀环境,附加高环空圈闭压力,使其更易发生失效风险,在设计及实际生产过程中,应重点管柱井底管柱安全风险。In deep-water,high-temperature,and high-pressure gas wells,the phenomenon of annular pressure is widely observed.Deepwater wells typically utilize subsea wellheads,which makes it impractical to depressurize annuli B and C.As a result,this poses safety hazards related to the potential failure of tubing strings under high annular pressures,high temperature and corrosion.Addressing the safety concerns related to tubing strings under high annular pressure in deep-water,high-temperature,and high-pressure gas wells,a predictive model was established for localized annular pressure.The model took into account the dynamic coupling of annular temperature,annular volume,fluid volume,and annular pressure changes resulting from thermal expansion and ballooning effects.It also considered the combined effects of annular pressure,high temperatures,and corrosion.A tubing string safety in deep water high temperature and high pressure gas well assessment method has been developed and applied to consider the influence of annular pressure,and the model s validation has been conducted.The results show that when considering the influence of annular pressure,the decrease in annular pressure over time is significantly smaller than the decrease in reservoir pressure.Simultaneously,the safety factor against external collapse of the tubulars decreases further as the service time increases.Furthermore,the pressure differential between the internal and external fluids in the tubulars gradually increases with well depth,making the lowermost sections of the tubulars more prone to failure.Under the combined effects of high temperature and corrosion within the wellbore,the safety factors for tubulars against internal pressure,external collapse,and tensile loads all experience varying degrees of reduction.Particularly,the lowermost tubing strings are susceptible to a harsh,high-temperature,and corrosive environment,as well as elevated annular pressure,which increases the risk of failure.In both the design and practical production processes,signifi

关 键 词：深水井 高温高压 圈闭压力 油管柱 安全评价 

分 类 号：TE38[石油与天然气工程—油气田开发工程]