Study on the crack propagation law of conglomerate based on linear elasticity and damage mechanics
Hydraulic fracturing is a critical technique to enhance the development efficiency of conglomerate oil and gas reservoirs.Based on the principles of linear elastic fracture mechanics and damage mechanics,establishes a theoretical model to describe the dynamic propagation of fractures in conglomerate reservoirs and investigates the dynamic propagation process of hydraulic fractures in such formations.The results indicate that hydraulic fractures in conglomerate reservoirs primarily propagate around gravel particles,and changes in gravel size have minimal impact on the direction of hydraulic fracture extension.Complex fracture networks are likely to form near horizontal wellbores,transitioning to simpler fractures farther from the well.With the increase of construction displacement,the numbers of multiple fractures initiated near the wellbore increases,but gradually being replaced by dominant fractures in distal regions.When construction displacement reach 10 m3/min,the maximum communication distance can reach 190 m.Low-viscosity(1 mPa·s)fracturing fluids tend to produce simple fractures,while medium(10～30 mPa·s)and high-viscosity(50 mPa·s)fracturing fluids are more likely to form complex fractures,forming advantages expansion in distal regions.High-viscosity fracturing fluids are easy to branch when encountering gravel,and form fracture patterns of interconnected vertical and horizontal fractures.With increase of horizontal stress difference,fracture complexity and the scale of the near-wellbore complex fracture network significantly decrease.When the horizontal stress difference reaches 10 MPa,dominant fractures are substantially reduced.This study provides essential guidance for optimizing hydraulic fracturing designs in conglomerate reservoirs.
万方数据
维普
