非均匀地应力作用下套管柱挤毁风险分析

Collapse Risk Analysis of Casing String under the Action of Non-Uniform Crustal Stress

油田开发过程中,套管损坏给油田造成了巨大的经济损失,需要利用套管外载计算模型对不同岩性地层进行套管抗外挤强度校核。采用弹性力学解析方法,建立了非均匀地应力作用下套管外载的计算模型,并分析了不同岩性地层条件下的套管外载。研究表明,套管所受的地应力外载比常规套管柱设计时的泥浆外载要大,在进行套管柱设计时必须考虑生产过程中由地应力产生的套管外载。在盐岩地层中套管的挤毁风险最大,页岩次之,在石灰岩地层中套管的挤毁风险最小。

In the process of oilfield development,casing damage will cause huge economic losses.Therefore,it is necessary to check the anti collapse strength of casing in different lithology strata using the external load calculation model of casing.The external load calculation model of casing under the action of non-uniform crustal stress is established by using the analytical method of elastic mechanics,and the external load of casing under different lithostratigraphic conditions is analyzed.The research shows that the external load of casing produced by crustal stress is larger than that produced by mud,so the external load of casing produced by the crustal stress must be considered in the design of casing string.In salt rock formation,casing collapse risk is the largest,followed by shale,and in limestone formation,casing collapse risk is the smallest.