Investigation Into Deep-Penetrating Horizontal Perforation Technique With High-Pressure Water-Jet

High-pressure water-jet deep-penetrating perforating technique, which utilizes hydrojet principle to cut a radial and long-distance, large-aperture, clean and pollution-free oil-drain channel in the rocks with high-velocity jetting of high-pressure water, is one of the most effective well-completion perforation techniques in application on near wells renovation improving inflow and injecting dynamics of oil-gas wells and realizing the enhanced production and increased injection. This technique is considered to be one of the most promising techniques in petroleum engineering. Centred on the efficiency and effect of high-pressure waterjets rock-breaking and route-orientated on the solution to the disadvantages of this technique, the full text expounds and makes conclusions from the following five aspects based on the exposed disadvantages of this technique when in practical use.(1) Summarize the research subject, engineering background and current situation at home and abroad of this project. Discuss the profit and defect of all the well-completion perforating methods. Thus conclude:High-pressure water-jet deep-penetrating perforating technique is advanced productivity in well- completion perforating technique of petroleum engineering in the world today. Submit the current problems of this technique and construct the technical line and research contents of this text based on them.(2) Study and discuss the series theory of high-pressure water-jet CFD research. Reveal numerical computation strategies of waterjets from general formal of time-equalization governing differential equation of waterjets motion. Thus conclude:Discretize governing differential equation with finite volume method (FVM) under second upwind discrete scheme. Choose standard k-εmodel of eddy model as nozzle jet is in the high Renold number turbulence state. Additional treatment with standard wall functions in the near wall region of nozzle. Consider jet to be uncompressible flow and select SIMPLEC algorithm of segregated solver to accelerate the convergence speed when solving the jet field.(3) Put forward the concept model of multi-jet nozzle head and analysize its key factors based on the practical operating environment of perforation. Study on optimization of relationship between key parameters and waterjets dynamic character of multi-jet nozzle head with the aid of CFD analysis. As a result, optimized design scheme of multi-jet nozzle head is reached. (4) Research on self-propelled perforating system and explain its self-propulsion mechanism in the theory. On these bases, self-propulsion motion equation of the perforating system is deduced. Thus conclude:Inside and outside differential pressure of nozzle head is the principal source of self-propulsion force of perforating system. The pressure drop along the line of high-pressure hose combined with self-propulsion force of nozzle head makes high-pressure hose in the state of stretched tight all the way when working. And this advances the self-propulsion motion of perforating system. Suction effect caused by forward nozzle-jet impact on the target plays an important role in promoting self-propulsion motion of perforating system. Appropriate increasement on system pressure and backward nozzle diameter benefits improving drill speed and motion stability of perforating system.(5) Put forward rotary and self-propelled nozzle head and dwell on the critical technical problems including special structure of the nozzle head, rotary dynamic seal and so on. On these bases, rotary motion character of the nozzle head is analysized in the theory.