During the exploitation of shale oil, the stress and pore pressure of the reservoir generally change, resulting in the deformation of the shale pore structure, which affects the oil migration in shale nanopores. Establishing an oil migration model and a permeability model that take into account the effects of reservoir stress and pore pressure is important for the numerical simulation shale oil development. In this paper, a new oil migration model in inorganic (IM) and organic (OM) nanopores of shale and a new shale apparent liquid permeability (ALP) model that consider the effects of reservoir stress and pore pressure are established. The molecular dynamics simulation data and experimental data are used to verify the validity of the proposed model. The results show that the model can reasonably describe the transport process of oil in IM and OM nanopores and calculate the ALP. The flow enhancement factor in inorganic and organic nanopores and the shale ALP are negatively correlated with the mean compressive stress and positively correlated with the pore pressure. When the shale bulk modulus is small, the flow enhancement factor and ALP are more sensitive to the stress and pore pressure. Moreover, the effects of stress or pore pressure on shale microscopic flow capacity which was evaluated by the flow enhancement factor and macroscopic flow capacity which was evaluated by ALP are consistent.

Mylonite coal is a representative of tectonically deformed coal and is a result of crushing original coal into fine coal grains under strong shear or long‐low tectonic stress. Because of its granular nature and the resultant inferior mechanical property, it is difficult to initiate fluid‐driven fractures within mylonitic coal reservoirs for enhancing coalbed methane recovery. The following explores a biomineralization method of microbially mediated calcium carbonate precipitation (MICP) to enhance the structural integrity and mechanical strength of mylonitic coal, enabling potential success for hydrofracturing. The experimental results indicate that the mechanical properties of mylonite coal are significantly enhanced after a short period of MICP treatment with ten cycles of treatments yielding a maximum uniaxial compressive strength (UCS) of 8.7 MPa and a maximum brittleness index of 0.218 approaching that of the hard coal. The increments in UCS and brittleness of biocemented mylonite coal show a positive correlation with the generated calcium carbonate content. Scanning electron microscopy (SEM) imaging indicates that the generated calcium carbonate precipitates first randomly occur on the particle surfaces, and then occupies the interstitial space until particle‐particle bonds are developed. The irregular morphology of coal particles results in two contact relations between particles, point contact and planar contact, causing a significant difference in biocementation effectiveness. Two microfailure patterns of biocemented coal with uniaxial compression are observed. One is that the coal particles are crushed, and the other occurs at the biocemented interface between the coal particles and calcium carbonate crystals.

The Hot Dry Rock (HDR) geothermal has huge reserves, clean and environmental protection, and is widely recognized as a renewable energy source with great development potential. Hot Dry Rock contains little or no fluid and is usually developed using Enhanced Geothermal System (EGS) technology. The efficiency of geothermal energy extraction depends on the fracture-making capacity and heat transfer capacity of reservoir and is directly related to the fracture-network structure transformation of reservoir. At present, the reservoir modification mainly includes hydraulic fracturing, chemical stimulation and thermal stimulation. However, how to increase the heat exchange area, increase the heat extraction channel, and stabilize the extraction of geothermal energy are still the challenges of efficient geothermal exploitation.