对井内岩石变形与塑性蠕变地层的思考

RESEARCH ON PLASTIC CREEP FORMATION AND ROCK DEFORMATION

在油气井钻井、完井、开采中经常遇到塑性蠕变地层,塑性蠕变地层蠕变是井壁失稳、套管损坏的最重要的因素之一。由于塑性蠕变地层种类繁多,特点各异,研究方法也不相同,分类研究更有针对性,但分类研究得出的结论极难推广到其它类型;统一研究结论更易推广,但统一研究不易找到统一的塑性蠕变地层的本质特征,所以现在尚无塑性蠕变地层的比较严格的定义。文章介绍了不同于地面材料的井下岩石受力特点、稳定变形特点、蠕变过程和特征,尝试给出了统一描述塑性蠕变地层的定义,并对蠕变地层意义进行了推广。

In the process of the drilling,completion and oil and gas exploitation,the plastic creep formation is often encountered,the formation creeping is one of the most important factors causing the wellbore instability and the casing damage.Due to the many types and the different characteristics of the plastic creep formation,the corresponding research methods are not the same.Usually the classification research method is more targeted;however,the conclusions from the classification research method are extremely difficult to be extended to other types.On the contrary,the conclusions from the unified research method are easier to be extended to other types,but the essential characteristics of the plastic creep formation are not easy to be found,so there is no stringent definition of the plastic creep stratum until now.This paper introduced the characteristics of the downhole rock force,the characteristics of the stable deformation and the creeping process.The definition of a unified description of the plastic creep formation was given,and the significance of the plastic creep formation was popularized.