Research On The Reflection Interface Exploration While Drilling Based On The Impulse Sound Source

With the deepening of oil and gas exploration and development,today’s emphasis is gradually shifting to small,hidden,unconventional oil and gas fields,but such reservoirs are often non-uniform,existing exploration technologies cannot meet both the detection depth and detection resolution.Therefore,a single well sound depth detection method based on plasma impulse sound source is proposed in this paper,which can detect the geological structure at a far distance,can control the bit to turn to the reservoir in advance,and reduce the dependence on the deflection ability of drilling equipment to increase the probability of hitting the target.In this paper,the basic principles of reflected acoustic logging are first studied,the time-distance relationship of different modes of waves is analyzed,and the basic theory of sound depth detection while drilling is derived;Then,the influence of the source distance,sound source frequency,reflection interface inclination and reflection interface distance on the received signal was studied through the finite element numerical simulation software,and to summarize the ability of plasma impulse sound source for deep detection.Finally,the existing data processing methods are studied to provide a theoretical basis for subsequent inversion.The research shows that the sound pressure level of the plasma impulse sound source is up to 256 dB,with the ability of deep detection;the dominant frequency band of the plasma impulse sound source under drilling conditions is around 7kHz,that is,the maximum detection depth can be reached at this frequency;the selection of the source distance should not be too large,according to the analysis of the time distance relationship,when the source distance is greater than 3.5m,it is beneficial to the separation and extraction of reflected waves.The conventional source distance can meet the needs of deep detection;when the source distance is less than 9m,it can effectively detect the wellside reflection interface with an inclination angle of 50 ° ~ 90 ° within 10 m.According to the simulation results of the two-dimensional axisymmetric model,the detection depth of the sound source can reach 40 m,and it has the possibility of further increasing the detection depth,which can meet the needs of the detection depth.The plasma impulse sound source has the ability to carry out deep exploration,which has guiding significance for the exploration and development of oil and gas resources.