Influence Factors Of Reflected Sound Field Of Plasma Sound Source In Open Hole Well

With the increase of energy demand such as oil,it is necessary to explore the stratigraphic structure and geological body.However,the traditional sonic logging and seismic exploration can not give consideration to both the detection resolution and the detection depth.In this paper,a sound depth detection technology based on plasma impulse sound source is proposed,which can emit high-power,high-energy impulse waves and detect relatively distant geological structures.Firstly,this paper introduces the basic theory of sonic deep detection technology,deduces the wave equation of impulse wave and the sonic field integral expression of plasma impulse sound source in open hole.Then the numerical simulation of the model of deep sonic detection in the well is compared with the real axis integral method to verify the feasibility of using the numerical simulation method.Next,by using numerical simulation method,the influence of sonic source emission frequency,dip angle of geological interface,horizontal spacing of geological interface and borehole diameter on the reflected sound field is explored,and the results are as follows: optimal emission frequency under each borehole diameter;the relationship between well diameter and optimized frequency;the conventional source distance can meet the detection requirements;the omni-directional detection can be realized by changing the angle of tool while drilling.Finally,the sonic field with or without crack,vertical crack with well axis and staggered crack with different dip angles are studied.and the influence of crack on wave amplitude and waveform and the variation law of various waves in fractures with different thickness are obtained.This study provides a theoretical basis and guidance for the practical application and design of the follow-up downhole acoustic deep detection.