Interaction behaviors between finite-scale natural and hydraulic fractures in hot dry rock geothermal systems

A deeper understanding of interaction dynamics between hydraulic and natural fractures remains essential, especially for finite-scale natural fractures. In this paper, a three-dimensional hydraulic fracturing model is developed by using the discrete lattice method, which can simulate meticulously the dynamic evolution of both hydraulic and natural fractures to offer a precise portrayal of their interaction and progression. The results show that hydraulic fractures often interact with finite-scale natural fractures in three distinct ways: bypassing, detour crossing, and crossing. Additionally, shorter interaction distances significantly bolster the likelihood of a hydraulic fracture successfully crossing a natural fracture. Furthermore, this research examines the impact of the magnitude of natural fractures on fracture interactions. A discernible positive correlation has emerged between the capability of hydraulic fractures to cross natural fractures and the length of their interaction with natural fractures. This work proposes the existence of two distinct interaction angles, α and β, between hydraulic and natural fractures. Notably, it underscores that only angles β significantly affect the fracture expansion capacity. This research presents valuable insights that facilitate the optimization of hydraulic fracturing in reservoirs with developed natural fractures.