A 3D analysis of the occurrence of fractures in hot dry rock reservoirs based on the spatial distribution of natural fractures

Hot dry rock (HDR) geothermal energy is a kind of widely distributed clean energy with huge reserves. However, its commercial development has been constrained by reservoir stimulation. In the early stage of HDR geothermal energy development, properly determining spatial distribution patterns of natural fractures in HDR reservoirs can effectively guide reservoir stimulation. This study analyzes the spatial distribution of natural fractures by using FracMan software based on the actual geological data and log data of well M − 2 in the Matouying Uplift area, Hebei Province. The fracture parameters are counted and Monte Carlo simulation technique is introduced to optimize the parameters, which makes the natural fracture model more accurate and reliable. Furthermore, this study simulates hydraulic fracturing using the model combined with the actual in-situ stress parameters and the construction scheme. As verified by fitting the changes in simulated wellhead pressure during hydraulic fracturing with the actual wellhead pressure data detected during construction, the methods for natural fracture modeling used in this study are scientific and reasonable. The preliminary prediction results show that the displacement design scheme with a pump displacement of 2.0-3.0 m3/min, 4.0-5.5 m3/min and 6-7 m3/min in the early, middle and late stages, respectively, has good fracturing effect. The results of this study can be utilized as a reference for preparing development schemes for HDR reservoirs.