The Optimization Of Horizontal Well Perforation In Fanshentun Oil-Field

More and more horizontal wells are applied while drilling technology is becoming perfect gradually. Perforation, being one of completions and stimulation, is used widely. So it is very important to study the productivity model of perforating horizontal well.In this study, the well is partitioned into many segments on the assumption of homogeneous formation. The whole three-dimension flow is divided into three parts using the pseudo three-dimension method: flow from infinite boundary into a vertical fracture, radical flow around the well bore, and convergent flow through perforations. Taking the influence of formation damage into account, a correlation equation between reservoir flow rate and pressure difference is obtained for each segment. According to the influence of perforation inflow on the main flow, the pressure drop along the horizontal well is attributed to friction and acceleration losses. A general pressure-drop expression is established based on the principles of conservations of mass and momentum. The model was verified by example, and sensitivity analysis of production of horizontal well was performed for perforation parameters.Afterward, in this study, the idea of connecting perforating technology and high energy gas fracturing is introduced. Differential equations set, including the borehole fluid movement equation, the kinetic equation of fluid in the well considering compressibility and hydraulic resistance, the motional equation of liquid and gas pushed into formation to create fracture and extend it, can be used to simulate the working process of gunpowder pressure generator. The length of fracture can be obtained under different geologic conditions with different explosive quantities. The method for determining fractured horizontal well productivity was investigated with the potential function principles and superposition principles. As a result, the well productivity varied with fracture length and fracture number can be calculated, so the high energy gas fracturing horizontal well model is built.A programme based on fixed step Runge-Kutta iterative method was developed to solve the computational model. The model was verified by actual example. Sensitivity analysis of production of horizontal well was performed for perforation parameters, perforation length, fracture number and quantity of explosive. The guidelines of optimization of perforation have been developed.