关于岩石侧压系数的认识误区

On Misunderstandings of the Rock Lateral Pressure Coefficient

针对石油工程中岩石侧压系数的预测问题,研究了介质的水平应力形成机理与侧压系数的计算方法,分析了水、土与岩石3种介质水平应力的区别与侧压系数的工程意义,并探讨了岩石的侧压系数预测方法。研究认为由于介质的结构与流动性不同,水和土的水平应力都是自重产生的,这与岩石的水平应力产生机理完全不同,岩石的水平应力主要是构造作用产生的。由于构造作用的强弱差异大,岩石的水平应力变化范围较大,侧压系数在-∞~∞,因此岩石的侧压系数不能沿用土介质侧压系数的计算方法。同时,岩石的侧压系数是通过实测地应力得到的,其预测结果并没有实际意义。

To address the issue of the prediction of rock lateral pressure coefficient in oil and gas engineering,we studied the formation mechanisms of horizontal stress in a medium,and methods for calculating lateral pressure coefficients.We analyzed differences in the horizontal stresses of three different media(water,soil,and rocks)and the engineering significance of the lateral pressure coefficient.Further,we investigated methods for predicting lateral pressure coefficients of rocks.We found that the mechanisms of horizontal stress formation in rocks are completely different from those in water and soil,due to differences in the structure and fluidity of these media.Horizontal stresses in soil and water are produced by their intrinsic weights,whereas horizontal stresses in rocks are primarily generated by tectonic actions.As these tectonic actions vary greatly in strength,the horizontal stresses of rocks also vary over a large range,and the rock lateral pressure coefficient varies between??1and+1.Therefore,methods for calculating the lateral pressure coefficient in soil media cannot be used to calculate the lateral pressure coefficient of rocks.In addition,since methods for predicting the lateral pressure coefficient are based on measurements of crustal stress,the predictions yielded from these methods are meaningless in practice.