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Numerical simulation on heat transfer and permeability of Fuyu oil shale reservoir after hydraulic fracturing was carried out by using thermal-fluid coupling analysis model. It is found that the fluid mainly flows out of the fracture along the oil shale bedding direction. However, as the temperature increases, the porosity increases and a little fluid flows out of the primary pores of the oil shale. The seepage field pressure shows a downward trend in the same section from the fracture perpendicular to the oil shale bedding. The heat conduction of fluid to oil shale formation was mainly in the direction of fracture. As the heating time increases, the oil shale cracks on both sides of the fissure, and with the porosity increase, the diffusion rate of nitrogen to the oil shale reservoir is also improved. After 40 days of heating, the oil shale around the fracture first reaches the cracking temperature. Between 60 and 100 days of heating, the average temperature of oil shale rises from 500 K to 650 K, and the whole oil shale can be effectively cracked. [ABSTRACT FROM AUTHOR]

Using the high voltage industrial frequency current to heat oil shale， the plasma channels can be formed in oil shale. The in-situ cracking of oil shale is realized by heating the oil shale with the generated plasma and the carbonized inner surface of the conductive channel. In this paper， a three-dimensional coupled model of oil shale was established by finite element analysis software， and the distribution of temperature field during the high frequency oil shale pyrolysis was obtained by numerical calculation. When the voltage is 1000V and the current is 5A， the temperature at the center of electrode， after 6 minutes heating， reached 597℃， and the temperature at the areas around the electrode 30mm away reached 347℃， meeting the pyrolysis demand of oil shale. With the increase of current， the increased temperature of oil shale during the same heating time showed a steady rise， and the range of effective pyrolysis also went up. According to the results of numerical simulation， using the high voltage industrial frequency to heat oil shale can gain a fast heating rate and high energy efficiency. [ABSTRACT FROM AUTHOR]