Study On Mechanism Of Well Washing With Negative Pressure Pulse Jet

During the process of oil production, the borehole wall and shotholes may deposit scale, salt and so on which affects the oil wells normal production. The technology of well washing with negative pulse pressure jet can improve the blocking of the shotholes in oil wells. It can stimulate the oil well production and the injection; increase the benefit of the oil field. This paper theoretically and experimentally analyze the effect of hydraulic parameters of the negative pressure pulse jet and the structure of oscillator on the amplitude of negative pulse, and the diffusing characteristics of the negative pressure pulse in the blocked perforation.In order to study the mechanism of well washing with negative pressure pulse jetting, use of artificial rock simulated hole sediment, many different experiments were designed, and the result shows that the impact of negative pulse can effectively decrease the intensity of the stemming; the negative pressure is very available to the permeability improving of the blocked perforation; the greater the pulse amplitude and the longer the cleaning time, the better the cleaning effect.The simulation experiments of the perforation cleaning with negative pressure pulse jet were taken. And the effect of the hydraulic parameters, the structure parameters of oscillator and the character of shotholes block on the pulse amplitude was studied. The results show that the pressure at the entrance of the negative pressure pulse jet modulator and the decrease of the ambient pressure. By sands filling to simulate the plug level, the diffusing characteristics of the negative pressure pulse jet in different plugging degree of shot holes were studied. The negative pressure pulse amplitude gradually decreases with the plugging degree, and the little the plugging degree, the more soft decreasing of pressure pulse attenuation, and the effective propagation distance is longer.