随着核废料处置、地下煤层气开发、地热资源的开采利用等领域的蓬勃发展，高温处理后岩石物理力学性质和渗透特征演化规律备受关注。为了对不同高温处理后花岗岩试样渗透特性进行研究，采用实验室试验的方法，设定围压10～30 MPa，进水口压力低于相应围压区间并逐渐增大，选用GWD-02A型高温炉对加工好的花岗岩试样进行高温加热，将花岗岩试样分别加温至200、300、400、500、600、800 ℃，采用全自动岩石渗透率测试系统对高温处理后花岗岩试样开展一系列渗透试验。通过测量不同温度作用后花岗岩试样直径、高度以及质量，得到不同温度花岗岩的密度；采用PDS-SW声波检测仪对不同高温处理后花岗岩纵波波速进行测试，得到波速与密度随温度变化情况；分析高温对花岗岩密度和波速的影响，得出高温处理后花岗岩试样体积流速与压力梯度的关系，分析得出渗透系数和导水系数与围压和温度的关系。研究结果表明：①随着温度的升高，花岗岩内部微裂纹逐渐发育，纵波波速与密度逐渐减小。②压力梯度与体积流速呈现线性关系，可用线性达西定律进行描述，随着温度的升高，等效渗透系数表现为逐渐增加的趋势，且温度越高，增大幅度越显著，试验结果可以用指数函数很好地拟合。③对于同一种高温处理后的试样，随着围压的升高，导水系数表现为减小的趋势。

With the vigorous development of nuclear waste disposal, underground coal-bed methane, the exploitation and utilization of geothermal resources, the evolution of physical and mechanical properties and permeability characteristics of rocks after high temperatures has attracted much attention.In order to test the permeability characteristics of granite samples after different high temperatures, the laboratory test method was used to set the confining pressure of 10～30 MPa, and the inlet hydraulic pressure is lower than the corresponding confining pressure interval and gradually increases.The GWD-02A high-temperature furnace is used to heat the processed granite samples at high temperature at 200, 300, 400, 500, 600 and 800 ℃,respectively. A series of penetration tests were carried out on the granite samples after high temperature using the fully automatic rock permeability test system. By measuring the diameter, height and mass of the granite samples after different temperatures, the density of the granite at different temperatures was obtained. The PDS-SW acoustic wave detector was used to test the longitudinal wave velocity of granite after different high temperatures, and finally the change of the wave velocity and density with temperature was obtained. On this basis, the influence of high temperature on granite density and wave velocity was analyzed, and the relationship between volume flow velocity and pressure gradient of granite sample after high temperature was obtained. Finally, the relationship between permeability coefficient and water conductivity coefficient and confining pressure and temperature was obtained. The results show that with the increase of temperature, micro-cracks in the granite gradually develop, and the longitudinal wave velocity and density gradually decrease，the relationship between volume flow rate and pressure gradient demonstrates to be linear and fits very well with the Darcy’s law. As the temperature increases, the equivalent permeability coefficient shows a gradual increasing trend, and the higher the temperature, the more significant the increase is. The test results can fit well with exponential function. For the same kind of samples after high temperature, as the confining pressure increases, the water conductivity shows a decreasing trend, and the rate of its decrease diminishes gradually.

0 引言

1 岩石渗透率测试试验过程

   1.1 试样准备

   1.2 试验方案

2 高温处理后花岗岩密度和波速的变化

3 高温处理后花岗岩渗透特性

4 结论