考虑腐蚀的环空带压井生产套管安全评价  

Safety Evaluation of Production Casing Considering Corrosion in Gas Well with Sustained Casing Pressure

作　　者：张智[1] 黄熠 李炎军 张超 曾春珉 

机构地区：[1]"油气藏地质及开发工程"国家重点实验室.西南石油大学,四川成都610500 [2]中海石油(中国)有限公司湛江分公司钻完井部,广东湛江524057

出　　处：《西南石油大学学报（自然科学版）》2014年第2期171-177,共7页Journal of Southwest Petroleum University(Science & Technology Edition)

基　　金：自然科学基金(50904050;51244007);国家科技支撑计划(2011BAE25B04);国家重大专项(2011ZX05023–004);四川省科技厅应用基础计划(2011JY0106);四川省省属高校科技创新团队建设计划(13TD0026)

摘　　要：对于含腐蚀性流体(CO2、H2S等)高温高压高产气井,一旦油套环空出现环空带压现象,封隔器以上生产套管将暴露在腐蚀环境中。受腐蚀、环空带压的相互作用,生产套管的服役寿命面临巨大挑战。研究了最大允许环空带压值的计算方法,结合实验室套管材质腐蚀速率测试数据,开展了考虑腐蚀缺陷的套管安全服役寿命评估。同时,研究了环空带压、环空带压与腐蚀相互叠加工况下套管的安全服役寿命。通过服役寿命设计,评估给定开采周期油套管剩余强度及安全状况,在有限的开采周期内,既要保证井筒本质安全,又降低开采成本。对于高温高压含腐蚀性气体的气井,一旦油层套管采用碳钢材质,则需要关注环空保护液的腐蚀测试,优选环空保护液体系,强化环空保护液的安全监管,避免由于套管的过度腐蚀而遗留安全隐患。In the high temperature and high pressure（HTHP）gas wells with CO2 and H2S,once sustained casing pressure builds up in the annulus of tubing and production casing,the production casing above packer will be exposed to the corrosive environment. Because of the interaction of corrosion and sustained casing pressure,production casing will face big challenges. A model of the max sustained casing pressure has been established;and based on the corrosion rates of casing,this paper predicts the safe service life of casing. Meanwhile safe service life has been predicted considering the sustained casing pressure and corrosion. The paper provides casing residual strength and its safety situation in limited production cycle by casing service life design,which will not only ensure the safety of casing but also cut the cost of production. For the HTHP sour gas wells, if the production casing is carbon steel,the performance of annulus protection fluid needs to be tested,and annulus protection fluid needs to be optimized;and in order to avoid casing security risks,it is necessary to strengthen security supervision annulus over protection fluid.

关 键 词：气井 二氧化碳腐蚀 服役寿命 安全评价 环空带压 

分 类 号：TE256[石油与天然气工程—油气井工程]