岩石孔隙率随地层深度变化规律研究

Research on the Law of Porosity of Rock with Depth

孔隙率是描述岩石物理、力学、渗流等特性的重要参数。通常 ,在研究自然条件下地层浅部岩石渗透问题时把岩石孔隙率可看作常数 ,但在研究工程活动条件下深部岩石渗透问题时 ,由于工程干扰力、地层岩石自重应力及构造应力等作用 ,岩石孔隙率随应力发生变化。通过某油田地层岩样室内三轴试验分析 ,发现岩石孔隙率随地层深度的变化为 4次多项式关系式 ,随深度增加而减小 ,并且在 6 0 0 0～ 70 0 0

Porosity is an important parameter characteristized physical, mechanical and seepage properties of rock. In general, when seepage problem of rock is studied in shallow underground rock in natural condition, porosity of rock is taken as a constant. However, porosity of rock changes with depth, geostress and engineering forces. Through analysis of triaxial test of rock samples, it is discovered that there is a quartic polynomial relation between porosity of rock and depth and porosity of rock decreases with depth increase. Porosity of rock approximates to a constant under 6000 m～7000 m depths.