Weiguo Liang

Problems of Evolving Porous Media and Dissolved Glauberite Micro-scopic Analysis by Micro-Computed Tomography: Evolving Porous Media (1)

In this study, the evolution phenomena and mechanism of porous media were analyzed according to the driving factors, i.e., external force, heat, seepage, coupled chemical reaction and seepage, coupled chemical reaction and heat flow, and live porous media. According to the evolution mechanism, the evolution can be categorized as natural evolution, artificial evolution, and natural–artificial evolution. Taking the dissolution of glauberite ore as the example, the detailed evolution characteristics and behavior were investigated. The evolution characteristics of pores and the residual porous skeleton were investigated using micro-computed tomography. The results indicate that (1) The variation of the dissolution thickness of glauberite with time follows a power function. (2) The total void ratio of the residual porous media remains almost the same and is typically in a range of 20–22 %. The diffusion coefficient of the residual porous skeleton is

THM (Thermo-hydro-mechanical) coupled mathematical model of fractured media and numerical simulation of a 3D enhanced geothermal system at 573 K and buried depth 6000–7000 M

0.013 ,hbox {cm}^{2}/hbox {h}

Micro-CT analysis of structural characteristics of natural gas hydrate in porous media during decomposition

0.013cm2/h. (3) In the process of glauberite dissolution, three zones are formed from the interface to the outside: a crystallization completion zone, a crystalline transition zone, and a development zone of dissolution and crystallization. The crystallization completion zone is formed after 15 h dissolution. The thickness of the crystallization transition zone and development zone of dissolution and crystallization is approximately 0.5–1.0 mm.

Deformation and instability failure of borehole at high temperature and high pressure in Hot Dry Rock exploitation

The fracture-pore double porosity medium is one of the most common media in nature, for example, rock mass in strata. Fracture has a more significant effect on fluid flow than a pore in a fracture-pore double porosity medium. Hence, the fracture effect on percolation should be considered when studying the percolation phenomenon in porous media. In this paper, based on the fractal distribution law, three-dimensional (3D) fracture surfaces, and two-dimensional (2D) fracture traces in rock mass, the locations of fracture surfaces or traces are determined using a random function of uniform distribution. Pores are superimposed to build a fractal fracture-pore double medium. Numerical experiments were performed to show percolation phenomena in the fracture-pore double medium. The percolation threshold can be determined from three independent variables (porosity n, fracture fractal dimension D, and initial value of fracture number N0). Once any two are determined, the percolation probability exists at a critical point with the remaining parameter changing. When the initial value of the fracture number is greater than zero, the percolation threshold in the fracture-pore medium is much smaller than that in a pore medium. When the fracture number equals zero, the fracture-pore medium degenerates to a pore medium, and both percolation thresholds are the same.