气饱和超压页岩的岩石物理建模研究

页岩的岩石物理建模随着页岩气勘探的深入而逐渐受到重视.现有的建模方法对孔隙压力的研究并不全面.本文认为页岩气对页岩弹性的影响可分为两个方面.第一个方面称为静态效应,定义为气体压力对页岩骨架的作用.第二方面称为动态效应,定义为页岩气本身对页岩弹性的作用.通过将孔隙纵横比与有效应力的关系、气体弹性参数与孔隙压力的关系嵌入岩石物理建模流程,实现静态和动态效应的作用.孔隙纵横比与有效应力的关系通过实测纵、横波速度标定,用于预测不同压力状态下页岩的纵、横波速度.本文方法虽存在一定的局限性,但提供了一种分析页岩弹性参数与孔隙压力相互关系的方法.

Rock physics modeling of gas-saturated over-pressured shale

With the development of shale gas exploration,rock physics modeling of shale has been attracted more and more attention.The existing methods are not comprehensive in the consideration of pore pressure.The impact of gas on shale elasticity can be divided into two aspects.The first is known as the static effect,defined as the effect of gas pressure on the shale skeleton.The second aspect,called dynamic effect,is defined as the effect of gas itself on shale elasticity.By embedding the relationship between pore aspect ratio and effective stress,and the relationship between gas elasticity and pore pressure into the rock physics modeling process,the static and dynamic effects are realized.The relationship between pore aspect ratio and effective stress which is calibrated by measured P-and S-wave velocity is applied to predict the P-and S-wave velocity of shale at other pressure condition.The method now has some limitations,but it provides a method to analyze the relationship between shale elasticity and its pore pressure.