Making the Transition from Discrete Shot Records to Continuous Wavefields - Methodology

A method that extracts the response of the earth from continuous wavefields on both the source and the receiver side is presented. Seismic data recorded continuously are treated over the entire time length at once. The source(s) can emit signals continuously while moving. The entire source wavefield contributing to each stationary receiver position is derived and used to extract common receiver gathers with the response of the earth. The trace spacing in the resulting gathers can be chosen in processing and corresponding anti-aliasing protection is applied. With the proposed method, no minimum listening time is needed since both the source(s) and the receivers are operating continuously. The emitted sound pressure levels are reduced by spreading the emitted energy out in time. Multiple sources can be operated simultaneously by designing each source such that the correlation between the wavefields emitted from each of them is minimized. In a companion paper (Kluver, T., Hegna, S., and Lima J., 2018, Making the transition from discrete shot records to continuous wavefields - Real data application: Expanded abstract submitted to the EAGE annual meeting) we discuss source design using existing equipment and show application of the proposed method on real data.