Optimization Of Multi-staged Hydraulic Fractures Of Horizontal Well In Low Permeability Reservoir

Multi-staged hydraulic fracture technology of horizontal wells is one of the key factors in the development of low permeability reservoirs. Production enhancement of low permeability reservoirs requires in-depth analysis of mechanisms governing hydraulic fracturing.Fracture twisting near the borehole can have a adversely affection on oil and gas production. This paper analyzed three different kind of rock-breaking models, and analyzed the rules of fracture propagation under different conditions. Compared with the fracture monitoring data, The best fracture propagation criterion is determined. Based on the criterion, the sensitivity factors of fracture propagation has been analyzed, and obtained the tendency of fracture propagation under different stress anisotropy、 fracture toughness and Poisson’s rate.Accurate estimation of fracture gradient is critical for hydraulic fracturing. Fracture gradient by traditional methods is greatly overestimated due to the ignorance of preexisting fractures. This article studied the mechanical properties of rock and established the fracability model, the prediction of fracability is based on the brittleness、fracture toughness、stress intensity factor, then selecting the proper fracability point.At the end of this text, integrated the fracability and completion, and taking well X1 as an example to optimize the fracture design. Based on the characteristic of reservoir, reducing the 10stages to 9stages,it is not only reduce the non-production time, but also reduce the cost. According to the numerical simulation, the optimized design can improve the production by 20%.