砂岩地下水封洞库各向异性渗透系数确定方法及应用

Determination Method of Anisotropy Permeability Coefficient for Underground Water Sealed Cavern in Sandstone Area and Its Application

砂岩地区建设水封石油洞库的关键问题之一是如何方便、准确地确定砂岩的各向异性渗透系数。文章通过对三维渗透张量矩阵的分析,利用空间几何原理推导渗透张量到标量数值转换的等效渗透系数计算公式,并结合常规压水试验数据,对张量矩阵渗透系数的计算结果进行修正。同时,提出采用钻孔超声波成像综合测试系统获取节理、裂隙的几何要素,作为张量矩阵计算的输入数据,将渗透张量矩阵和常规压水试验相结合,最终建立了岩体各向异性渗透系数的确定方法。工程实例证明该方法操作方便,结果准确。

Accurate and easy determination of anisotropy permeability of sand stone is one of key points for construction of a water-sealed cavern in the sandstone.A calculation formula of equivalent permeability coefficient for conversion from permeability tensor to scalar value was deduced in light of the spatial geometric principles based on an analysis of three-dimensional permeability tensor matrix,the calculation results of tensor matrix of permeability coefficient were modified on the basis of conventional water pressure test data.It suggests that borehole ultrasonic imaging test system should be adopted to obtain geometric factors of joints and fractures which are the input data of tensor matrix calculation,and a determination method of anisotropy permeability coefficient of sandstone was established by combination of permeability tensor matrix and conventional water pressure test results.Engineering cases have proved that this method is easy to operate and the results are accurate.