Abstract:When convective heating technology is used to heat underground oil shale, the natural fissure formed by the ground stress in the oil shale layer and the artificial fissure formed by hydraulic fracturing together constitute the fluid migration channel. The fissure can provide a passage for the hot fluid to increase or decrease the heating range of the oil shale; it can also affect the heating rate of the oil shale by changing the flow velocity of the hot fluid. Therefore, it is very important to fully understand the influence of underground fissures on the heating effect of oil shale and determine the reasonable well placement method for oil shale mining. By using the commercial simulation software ANSYS, the complex underground crack problem is simplified to establish a three-dimensional model, and the process of heating the oil shale with heat fluid injection is numerically simulated. By simulating the temperature field of oil shale in-situ hydrothermal mining, the heating effect of oil shale under different fracture locations and occurrence is explored and analyzed. The simulation results show that the steady state can be reached after heating for 5 years. when the heating well is far away from the open crack, and the production well is located between the heating well and the open crack, the oil shale heating effect is better . When the direction of the well group connection is perpendicular to the fracture direction, the heating effect is better; when the open fracture is perpendicular to the rock formation, the heating effect is the better .