环空渗流诱发环空带压机理研究  

MECHANISM STUDY ON SUSTAINED CASING PRESSURE CAUSED BY GAS MIGRATION IN ANNULUS

作　　者：张智[1,2] 曾韦 彭小龙[2] 王波[2] 李海洋[2] 施太和[1] 

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 [2]西南石油大学石油工程学院

出　　处：《钻采工艺》2014年第3期39-41,8,共3页Drilling & Production Technology

基　　金：国家自然科学基金项目(编号:50904050;51244007);国家科技支撑计划(2011BAE25B04);国家重大专项"大型油气田及煤层气开发"(2011ZX05023-004);四川省科技厅应用基础计划(编号:2011JY0106);中央财政支持地方高校发展专项资金"石油与天然气工程国家一级学科"项目;四川省省属高校科技创新团队建设计划(13TD0026)共同资助

摘　　要：随着天然气井的开发,持续环空带压问题越来越突出,对安全生产造成了严重的威胁。造成环空带压的原因较多,主要可分为温度效应诱发的环空带压、密封失效诱发的环空带压以及气体运移诱发的环空带压。针对日益严重的环空带压问题,文章根据井身结构、天然气性质,对由气体运移诱发的环空带压进行了研究,并建立了由此诱发的环空带压计算模型。在建立数学模型过程中,将天然气在水泥环中的渗流简化为低渗透多孔介质的不稳定渗流,并在漂移模型基础上建立了气体在水泥环上部液柱中的瞬态运移模型。根据某气井数据进行了实例分析计算,并记录12.7 mm针型阀放压和关闭针型阀24 h内压力下降曲线和压力上升曲线。结果表明,所建模型计算出的环空带压值与现场检测数据相吻合,这为SCP风险评估和制定解决方案提供了依据。With the development of gas wells,sustained casing pressure( SCP) which is a serious threat to safety production has become more and more prominent. SCP could be resulted in several mechanisms such as thermal expansion,tubular mechanical failures,and gas migration. According to wellbore structure and natural gas properties,SCP caused by gas migration was analyzed and a computational model was built. Gas migration in cement mantle could be considered as unsteady flow in low permeability porous medium,and based on drifting model,transient model of gas migration above the cement mantle had been built. The value of SCP of a gas well had been calculated as an example,and the trend of SCP changes had been recorded within 24 hours. Calculation results fit with the actual field data which provides basis for SCP risk assessment and formulating solution.

关 键 词：气井 环空带压 气液两相流 气体运移 风险评估 

分 类 号：TE38[石油与天然气工程—油气田开发工程]