利用岩石力学理论研究了岩石的变形机制问题。岩石的孔隙度是骨架颗粒排列方式和粒度分布的函数，与粒度大小无关。岩石孔隙度变化曲线可以分成压实阶段和压缩阶段。压实阶段的孔隙度变化与应力有关，压缩阶段的孔隙度基本为常数，与应力无关。石油地质学一直把压缩阶段称作欠压实阶段，把孔隙度不再减小认为是孔隙憋压所致，并用等效深度法计算了地层压力的大小。实际上等效深度法并不等效，该方法把孔隙度视为地层压力的函数是缺乏理论根据的。用等效深度法计算得到的压缩阶段地
层皆为异常高压的认识也是不符合实际的，用等效深度法预测地层压力没有任何的实际意义，会误导相关内容的研究。

Based on the theory of rock mechanics, the deformation mechanismof rock was studied. The porosity of rock depends on the arrangements and the size distribution of grains, not the size of grains. The porosity curve can be divided into the compaction portion and the compression portion. Porosity in the compaction portion changes with stress, while the porosity in compression portion keeps constant and does not change with stress. However the theory of petroleum geology takes the compression portion as the undercompaction portion, and the constant porosity as the result of increased pore pressure. The equivalent depth method is used to calculate the pore pressure. Actually the equivalent depth method is not equivalent. The dependence of porosity on the pressure is lack of theoretical basis. The abnormal pressures in the compression portion by the equivalent depth method are not consistent with practice. Prediction of pressure by the equivalent depth method is meaningless in practice which maymislead the relative researches.