储层压实引起套管失效的机理研究

STUDY ON MECHANISM OF CASING FAILURE INDUCED BY THE RESERVOIR COMPACTION

套管失效问题是一个世界性的难题 ,严重影响了石油工业的经济效益。其典型失效形式包括套管腐蚀、径向变形、剪断等 ,失效原因包括油井水腐蚀、层间滑动引起的剪切作用和非均匀地应力作用等 ,其中油藏压实是诱发失效原因的主要因素之一。为了弄清油藏压实对套管损坏的影响规律 ,在对地层发生压实的原因、机理进行了研究的基础上 ,对地层压实引起的套管失效机理进行了详细分析 ,提出了预防或减少压实地层套管失效的对策 ,即提高套管设计水平 ,确定合理井身结构 ,维持合理注水压力 ,采用厚壁套管等。

Casing failure is a worldwide problem in oil industry and severely impacts the economic benefits. The typical forms of the casing failure includes casing corrosion, radial deformation and shear etc., and the causes include corrosion of the formation water, non-uniform load on the casing initiated by the formation deformation or the hydration of the shale, shear initiated by formation sliding. As to the casing failure induced by the reservoir compaction, the reasons and the mechanisms of the reservoir compaction were studied; furthermore, the mechanisms of the casing failure in the compaction reservoir were analyzed and presented in detail. Measures for controlling casing failure in the compaction reservoir are put forward, which include increase the level of the casing design and determine suitable casing program; inject water to maintain the formation pressure, use the non-API thick wall casing, etc.