Fig. 1

Schematic of phase-field method[31]"

Fig. 2

Schematic of computational domain and boundary conditions for model convergence example"

Table 1

Input data for convergence study example"

Fig. 3

Fracture phase field distribution contours at the end of injection under three different time steps"

Fig. 4

Fluid pressure distribution contours at the end of injection under three different time steps"

Fig. 5

Pressure at injection point versus injection time with three different time steps"

Fig. 6

Schematic of computational domain and boundary conditions for influencing factors study"

Table 2

Simulation parameters which affect hydraulic fracture extension trajectory"

Fig. 7

Fracture propagation processes for different in-situ stresses at an approach angle of 30°"

Fig. 8

Fracture propagation processes for different in-situ stresses at an approach angle of 45°"

Fig. 9

Fracture propagation processes for different in-situ stresses at an approach angle of 60°"

Table 3

Intersection behaviours of the hydraulic and natural fractures for different approach angles and in-situ stress differences"

Fig. 10

Snapshots of fracture phase-field evolution contours corresponding to injection rate of 0.001 5 m2/s"

Fig. 11

Snapshots of fracture phase-field evolution contours corresponding to injection rate of 0.006 m2/s"

Fig. 12

Pressure at injection point versus injection volume for three different injection rates"

Fig. 13

Snapshots of fracture phase-field evolution contours corresponding to fluid viscosity of 3 mPa·s"

Fig. 14

Snapshots of fracture phase-field evolution contours corresponding to fluid viscosity of 5 mPa·s"

Fig. 15

Pressure at the injection point versus the injection time for three different fluid viscosities"

Fig. 16

Comparison diagram of model calculation results and experimental results"