Seismic velocity analysis method based on chaotic system

Abstract

Summary Strong random noise in onshore exploration and swell noise in marine exploration always degrade the quality of seismic data and affect accuracy of velocity analysis. Duffing oscillator (chaotic) system is a nonlinear system that is immune to noise, but it is more sensitive to particular periodic signals. In this work, we propose a Duffing oscillator system to detect seismic event with the purpose of acquiring velocity field in strong noise background. We develop a new grid partition method (GPM) to judge the state of Duffing oscillator system. The system state is quantitated by the proposed method and minimum values of judging parameters indicate accurate velocity field away from strong noise. Results of applying the method to synthetic example demonstrate that the Duffing oscillator system with GPM is effective for seismic velocity analysis, especially in condition of strong noise. The field data example shows that the proposed method, compared with traditional velocity analysis, is less influenced by swell noise in marine seismic data.