Parameters Optimization of Fractured Horizontal Well of Overall Fracturing Well Patterns in Ultra-low Permeability Oilfield

Fluid flowing in ultra-low permeability reservoirs present non-linear characteristics. Based on the equivalent flowing resistance method and superposition principle with flowing field partition principle, non-Darcy flowing model of two phases for overall fracturing combined well pattern with fractured horizontal well and fractured vertical well is established with mutual interference between multi transverse fractures. It analyses the parameters influences of hydraulic fractured horizontal well on development effectiveness in different well patterns, in order to guide the development program design of overall fracturing. The simulated results indicated that the relationship between the horizontal length with the optimum number of cracks of fractured horizontal well is linear, and the optimal angle of fractured horizontal well and horizontal well bore within rectangular combined well pattern overall fracturing is 50°~80 °. The optimum hydraulic fracture conductivity in ultra-low permeability reservoirs is 10~15D·cm. The results also show that the equal arrangement of cracks along the horizontal well bore that longer cracks near the ends and shorter cracks in the middle is suggested as an optimal development way of fractured horizontal well.