Investigations on the Directional Propagation of Hydraulic Fracture in Hard Roof of Mine: Utilizing a Set of Fractures and the Stress Disturbance of Hydraulic Fracture

Abstract Directional fracturing is fundamental to weakening the hard roof in mine. However, due significant stress disturbance mine, principal stresses present complicated and unmeasurable. Consequently, designed hydraulic fracture (HF) extension path always oblique stresses. Then, HF will deflecting propagation, which restrict weakness of roof. In this work, we proposed an approach drive propagate directionally roof, utilizing a set fractures their disturbance. approach, directional conducted via sequential three linear distribution slots. The disturbed produced by first (in middle) are utilized subsequent fracturing. combined constitute roughly trajectory rock, i.e., To validate cohesive crack (representing rock process zone (FPZ)) model coupled with extended finite element method (XFEM) was employed simulate 2D process. benchmark above simulation firstly conducted, presents high consistency between results experiments. published geological data Datong coal mine Shanxi, China) model, various differences (2~6 MPa) directions (30°~60°). show that disturbing significantly inhibits propagation fractures. More specifically, along direction parallel initial minimum stress, distance 2~3 times higher than deviates from only 2°~14°, reduced 76%~93% compared traditional single fracture. This newly can enhance ability more effectively conveniently complex unmeasurable field. Besides, also provide references for oil-gas geothermal reservoir.