Full waveform inversion and distance separated simultaneous sweeping: a study with a land seismic data set

Dense, wide-aperture and broad frequency band acquisition improves seismic imaging and potentially allows the use of full waveform inversion for velocity model building. The cost of dense acquisitions however limits its applicability. Blended or simultaneous shooting could lead to a good compromise between cost and dense acquisition, although the cross-talk between simultaneous sweeps may reduce imaging capabilities. Onshore, a compromise is achieved with distance separated simultaneous sweeping acquisition, because the shots are easily separated when the processing focuses on pre-critical reflected events. Full waveform inversion for velocity model building however relies on post-critical reflected, refracted and diving events. These events can interfere in a distance separated simultaneous sweeping acquisition. By using a single vibrator, single receiver data set recorded in Inner Mongolia, China, a distance separated simultaneous sweeping data set is created to study the robustness of full waveform inversion in this acquisition context. This data set is well suited for full waveform inversion since it contains frequencies down to 1.5 Hz and offsets up to 25 km. Full waveform inversion after a crude deblending of the distance separated simultaneous sweeping data set leads to a result very similar to the one obtained from the single vibrator, single receiver data set. The inversion of the blended data set gives a slightly less good result because of the cross-talk but it is still quite satisfactory.