Parsimonious surface wave interferometry

Abstract

To decrease the recording time of a 2D seismic survey from a few days to one hour or less, we present a parsimonious surface-wave interferometry method. Interferometry allows for the creation of a large number of virtual shot gathers from just two reciprocal shot gathers by crosscoherence of trace pairs, where the virtual surface waves can be inverted for the Swave velocity model by wave-equation dispersion inversion (WD). Synthetic and field data tests suggest that parsimonious wave-equation dispersion inversion (PWD) gives S-velocity tomograms that are comparable to those obtained from a full survey with a shot at each receiver. The limitation of PWD is that the virtual data lose some information so that the resolution of the S-velocity tomogram can be modestly lower than that of the S-velocity tomogram inverted from a conventional survey.

Near-surface real-time seismic imaging using parsimonious interferometry

“…Similar to virtual refraction arrivals generated by the PI method, virtual shot gathers containing surface waves can also be generated at every geophone in the recording survey 11 . Details for generating the virtual surface waves are given in 11 , the general theory is in 12 and the Supplemental Information section.…”

“…This enormous increase in the number of traveltime picks and associated rays, compared to the many fewer traveltimes from the two reciprocal and several infill shot gathers, provides for increased model resolution and a rapid delineation of the fluid-flow properties 10 in the subsurface. Parsimonious interferometry can also be used for rapidly reconstructing the S-velocity model from recorded surface waves, as demonstrated by 11 .…”

“…As we will show, the time-lapse tomograms are in qualitative agreement with 3D fluid simulations and laboratory experiments. We also apply surface-wave parsimonious interferometry 11 to the Rayleigh waves and invert for the S-wave velocity tomogram. Both the Vp and Vs tomograms can then be used to compute the time-varying Vp/Vs tomograms, which indicates the degree of temporal viriations of water saturation in the subsurface.…”

Time-lapse parsimonious refraction interferometry: A field experiment

“…This enormous increase in the number of traveltime picks and associated rays, compared to the many fewer traveltimes from the two reciprocal and several infill shot gathers, provides for increased model resolution and a better condition number with the system of normal equations . This proposed technique is also valid for surface waves as shown by Li et al, (2018). In our current work we use a field experiment to demonstrate the feasibility of parsimonious refraction interferometry for tracking the fluid flow of water injected into a sand dune.…”

“…The time-lapse PRI method was tested using synthetic and field-data examples (Fu et al, 2017;Hanafy and Schuster, 2017;Li et al, 2018). We now use field data to test the PRI method in its ability to temporally track the percolation of water through a sand dune after injecting 12 tons of water into the subsurface.…”