Numerical simulation of the fracture propagation of linear collaborative directional hydraulic fracturing controlled by pre-slotted guide and fracturing boreholes

摘要

Directional rock rupture is an important and common problem in the engineering of rock breaking. Directional rock rupture can be effectively achieved by linear collaborative directional hydraulic fracturing controlled via pre-slotted guide and fracturing boreholes. In this paper, the RFPA2D-Flow software is utilized to verify the experimental results of linear collaborative directional hydraulic fracturing controlled by pre-slotted guide and fracturing boreholes, and its basic law is studied. We find that: (1) By comparing with hydraulic fracturing controlled by a single pre-slotted fracturing borehole or by a pre-slotted fracturing borehole and guide boreholes without pre-slots, the linear collaborative directional hydraulic fracturing controlled by a pre-slotted guide and fracturing boreholes has a better effect and a larger directional expansion range. (2) The greater the length of the pre-existing slot, the more favourable the induction of directional expansion of the hydraulic fracture along the direction of pre-existing slot. (3) A smaller angle between the line connecting the borehole centres and the maximum principal stress and a smaller coefficient of horizontal stress difference correspond to a smaller deflection angle of hydraulic fracture propagation (i.e., the angle between hydraulic fracture propagation and the pre-existing slot), which is more conducive to directional expansion of the hydraulic fracture.