High-Multiplicity Simultaneous Sources and Marine Vibrator Acquisition Effects

Abstract

Summary High-fidelity marine seismic vibrators allow control of the phase of the emitted seismic wavefield. Phase control of the seismic source can allow new simultaneous-source encoding techniques. These techniques may allow highly efficient seismic acquisition without sacrificing data quality. One approach that uses phase control is phase sequencing, where the emitted source wavefield phase is changed in a non-random way from shot-to-shot, allowing manipulation of data in the frequency-wavenumber domain. Combined with wavefield reconstruction, phase sequencing allows separation of simultaneous sources with minimal residual crosstalk. An important consideration when evaluating such techniques is that marine seismic vibrator deployment and utilization will be different from an air-gun source. For example, a marine vibrator source array is likely to move while emitting energy, it may have different array elements distributed at different depths, it will emit swept rather than impulsive waveforms, and it may behave differently in the presence of a rough sea. We demonstrate the separation of high-multiplicity simultaneous sources using phase sequencing, before discussing marine-vibrator specific acquisition effects. The impact of these acquisition effects will be demonstrated in future publications.