Study on Numerical Simulation of Borehole Azimuthal Acoustic Reflection Imaging Logging in Adjacent Well Positioning

To verify the feasibility of applying the azimuthal acoustic reflection imaging logging technology in the positioning of adjacent wells, and to address the issue that existing technologies mainly focus on the fixed distance between the target well and the measurement well without systematically studying the PP echo characteristics at different distances, in order to meet the requirements of anti-collision in shallow sea well clusters and rescue detection and positioning in accident wells, the three-dimensional finite difference method is used to numerically study the echo wave field of the target well beside the well when a monopole acoustic source radiates acoustic waves and a cylindrical array receives the acoustic waves. By changing the radial distance between the two (1, 2, 3, 5, 10 m), the relative amplitudes of different mode echoes and their relationship with the azimuth of the target well are analyzed. At the same time, the three-dimensional spatial scanning imaging processing is used to forward model the waveform data and obtain the horizontal plane target well imaging diagram perpendicular to the well axis. The research results show that: ①Regardless of the radial distance between the target well and the measurement well, the PP echo characteristics recorded by the receiver array are relatively obvious, and the rate of decrease in the relative amplitude of the PP echo gradually slows down with the increase in the radial distance (for example, the echo amplitude is 146.37% of the sliding longitudinal wave amplitude at a radial distance of 1 m, 7.32% at 5 m, and 3.53% at 10 m). ②The receiver unit closest to the azimuth of the target well records the earliest arrival time and the strongest amplitude of the echo, and the azimuth angle corresponding to the maximum echo amplitude is consistent with the azimuth of the target well (90°). As the radial distance increases, the arrival time of the echo gradually becomes later and the maximum amplitude gradually decreases. ③Based on the PP echo horizontal plane scanning imaging, the azimuth (90°) and radial position of the target well can be accurately determined (the imaging position is 2.15 m at a radial distance of 2 m, 5.20 m at 5 m, and 10.10 m at 10 m), and the single shot point acquisition and horizontal plane scanning imaging mode can achieve synchronous measurement and processing and real-time detection. ④When the radial distance is relatively close, the characteristics of different mode echoes (PP, PS, SP, SS echoes) of the target well are obvious, and when the distance is relatively far, the amplitude of the PP echo is relatively large, while the amplitudes of the converted waves (PS, SP echoes) and SS echoes are relatively small. The conclusion is that the azimuthal acoustic reflection imaging logging technology is feasible for application in the positioning of adjacent wells. The PP echo based on the monopole acoustic source radiating acoustic waves and the cylindrical array receiving the acoustic waves can effectively locate the adjacent target well, and the horizontal plane scanning imaging can accurately determine the azimuth and radial position of the target well and achieve real-time detection.