Numerical simulation of interaction of hydraulic fracture and natural fracture based on the cohesive zone finite element method

• We model the interaction of hydraulic and natural fractures in the porous medium.
• The smaller the approaching angle, the easier for natural fracture propagating.
• Smaller differential in-situ stresses will make HF deflecting into NF.
• Decreasing cementing strength will enlarge the natural fracture geometry.

The fracture diagnostic technology reveals that complex fracture network plays a key role in shale gas production. In this paper, a new model based on the cohesive zone method coupling stress-seepage-damage filed is developed to simulate the interaction between hydraulic fracture and natural fracture without introducing the crossing criterion. The initiation and propagation of hydraulic fracture and natural fracture are simulated to study the intersection process including hydraulic fracture encounters natural fracture and extends separately. The effects of in-situ stress and approaching angle on the intersection between hydraulic fracture and natural fracture are discussed. And the effect of natural fracture cementing strength on fracture geometry is simulated. The smaller the approaching angel and differential stress, the easier for natural fracture initiating and propagating. These findings could provide theoretical guidance for predicting the generation of complex fracture network.