Interaction of a hydraulic fracture with a hole in poroelasticity medium based on extended finite element method

The purpose of hydraulic fracturing or acid fracturing is to use artificial fractures to connect the caves and establish high-conductivity oil and gas flow channels between the caves and the wellbore, the essence of the process is the interaction of a hydraulic fracture with a hole in poroelasticity medium. While the interaction mechanism between hydraulic fracture and hole in the poroelasticity medium remains unclear. In order to clarify the process, a seepage-free flow-mechanical coupling extended finite element method (XFEM) model was established. In the numerical study, the curved beam fracture propagation path with holes and initial preset fracture was calculated, and fracture connecting holes under triaxial stress was simulated. The results showed that the fracture path deflection degree was reduced by fluid pressure in the holes. Under triaxial stress, hydraulic fractures tend to extend toward the direction of the maximum horizontal principal stress. When the angle between the perforation direction and the maximum horizontal principal stress was 30 degrees, the hydraulic fracture was deflected quickly in the direction of the maximum horizontal principal stress. As the angle was increased, the hydraulic fracture took more time to deflect toward the direction of the maximum horizontal principal stress.