A Model for Multiple Hydraulic Fracture Propagation with Thermo-Hydro-Mechanical Coupling Effects

Abstract

In this study, a coupled thermo-hydro-mechanical model to simulate multiple hydraulic fracture propagation is presented. Fracture propagation with elastic deformation is described by using a displacement discontinuity method. The temperature distribution and induced thermal stress are calculated via a semi-analytical method in an explicit way. An iterative scheme is proposed to solve the coupling between fracture propagation with fluid flow and induced thermal stress. The numerical model is validated against related analytical solutions. Several numerical cases are modeled to investigate the controlling factors for uniform growth of multiple fractures. Results show that using non-uniform fracture spacings and proper increasing the spacing for fractures away from the heel of wellbore promote the uniform growth of multiple fractures by comparison with using uniform fracture spacings. Increasing the perforation diameter for the middle cluster also works. Besides, single-wing fracturing could greatly improve the uniform growth of multiple hydraulic fractures. Finally, it shows that the thermal stress has a significant influence on fracture geometrical size but has limited effect on fracture propagation path. In addition, the thermal effect promotes the uniform growth of multiple fractures.

Keywords

• multiple fractures
• hydraulic fracturing
• stress shadowing
• thermal stress
• displacement discontinuity method