荷载条件下泥页岩热物性参数试验研究

Experimental study on thermal property parameters of mud shale under loading condition

岩石热物理性质与其矿物组成、内部结构、温度、含水率等有关外,还受赋存状态包括应力大小、方向等的显著影响。岩石热物性参数的准确获取对非常规油气资源开发、深部矿产资源开采和地热能开发利用等岩体工程设计、实施具有重要意义。结合某油田工程的泥页岩为研究对象,开展不同应力水平实时加载时的岩石热物性参数试验研究,结果表明:岩石在各向同性和各向异性条件下,其应力条件都对热物性参数有显著影响,且初始加载阶段更为明显;各向同性条件下整体上应力越大,导热系数和比热容越大;岩石热物理性质有显著的各向异性特征,轴向(沿加载方向)上导热系数与热扩散系数随应力增加而增大,径向(垂直加载方向)上随应力增大而减小,但整体上变化速率均呈初期加载时较大,后期趋缓的变化规律。

The thermophysical properties of rock are not only related to their mineral composition,internal structure,temperature and water content,but also significantly affected by the stress state,including the magnitude and direction of stress.The accurate acquisition of rock thermophysical parameters have great significance to the design and construction of rock engineering,such as the development of unconventional oil and gas resources,the exploitation of deep mineral resources and the development of geothermal energy.Using the mud shale of an oil field project as the research object,a series of experimental researches were completed,in order to measure the thermophysical parameters of rock under real time loading at different stress levels.The results show that the stress conditions of rock have a significant impact on the thermophysical parameters under isotropic and anisotropic conditions,and it is more obvious at the initial loading stage.Under isotropic condition,with the stress increasing,the thermal conductivity and specific heat capacity increased at the same time.The thermophysical properties of rock have significant anisotropic characteristics,the thermal conductivity and thermal diffusion coefficient increase with the increase of stress in the axial direction(along the loading direction),and decrease with the increase of stress in the radial direction(vertical loading direction),and the overall change rate shows the distribution characteristic of faster in the initial loading stage and slower in the later stage.