Mechanism of Fracture Generation in the Hole and Research on Optimization Design of Drilling Fracture Parameters

摘要

In order to increase the production of low permeability reservoir inclined or straight well, establish effective communication between the sand and improve development effect. For Daqing periphery low permeability oil field properties, such as large sandbody permeability difference, plane fast phase transition, narrow sandbody and scattered distribution. A straight and inclined well hydraulic fracture stimulation modification technology research and field application was launched. Studied the mechanism of crack generation in the hydraulic drilling hole and analyzed factors of crack situation in the hole of hydraulic drilling fracture, given parameter optimization method of hydraulic drilling fracturing, carried out hydraulic drilling fracturing on spot well selection test. The results show: At reservoir heterogeneity geo stress conditions, after the hydraulic drilling, the fracture cracks always rupture on contact surface of well and hole and then the crack extend along the direction of maximum horizontal stress. So reservoir heterogeneity is a necessary condition for generation of cracks in the hole. To make cracks in a certain position of hole after the hydraulic fracturing, reservoir heterogeneity must be a prerequisite, that there exists natural fractures in reservoir or geo stress heterogeneity. Pressure curve and fracture pressure curves intersect multiple cases. In these cases there will be many perforations along the crack. Considering the stress orientation, petrophysical, sedimentary facies, hole geometry parameters, the overall design system of hydraulic drilling fracturing parameters optimization is given. On spot selected well got a good effect. Liquid production increased to 4.8 from 1.7 tons. Oil production increased to 4.2 from 0.9 tons.