Performance Analysis And Optimization Of The Particle Pulse Jet Directly Modulated In Bottom Hole

As the depletion of shallow layer oil and gas resources, finding oil and gas in deep and hard formation has become the point of currently exploration and development, and the key problem is the improvement of deep well penetration rate. The pulsed water jet drilling technology suck-in annulus fluids is proposed to take full use of the bottom-hole hydraulic power and promote the rock breaking efficiency, and explore the performance analysis and optimization method with both important theoretical and practical value.Firstly, pulsed jet directly modulated bottom particle is proposed based on the idea of pulsed particle jet, completed the principles of design of matching modulated jet drilling tool which is self-excited pulsed jet suck-in annulus fluids drilling tool. The modulation mechanism is obtained by analyzing the flow characteristics of two-phase flow field. And also found that modulation tool can be achieved topical negative pressure to let the annular particles in to modulate the pulsed particle jet, no matter how the confining pressure, particle size and particle density parameter variation, demonstrate the feasibility of the principle of modulation tools. Secondly, he LES (large eddy simulation) numerical analysis method is adapted to analyze flow transient and fluctuation characteristics, the results showed that this jet modulation tool can be inhaled particles into annular chamber, and modulated continuous jet into pulsed jet, and the structural parameters take significant effect on the ripple effect. Then, developed a prototype to conducted experiments of rock breaking based on the results of the large eddy simulation, analyze the effect of structural parameters change on the rock-breaking performance of the particle pulsed water jet. It was found that the bigger the outlet velocity of the oscillation cavity is, the better the rock-breaking effect could be obtained, and there is a good linear correlation between them, and there is a poor correlation between other oscillation cavity and rock-breaking. Finally, the multi-factor orthogonal simulation experiments have been done and the pulsed structure has been optimized according to the velocity oscillation, and the simulation results are in good agreement with the lab experiments. And then, several groups of optimum structure modulation tools for rock-breaking test to select the optimal structural parameters. It is proved that by the large eddy simulation and experimental research combined analysis revealed the mechanism of self-excited pulsed jet suck-in annulus fluids modulation tool is feasible.In this paper, experimental research and numerical simulation is combined to research the modulate method and mechanism of modulation. And also find a method to optimize the modulation tool structure. The simulation results are in good agreement with the lab experiments, which indicates the structure optimization of the self-excited pulsed water jet is feasible. The research lays a basic for the design and optimization of the pulsed water jet structure.