Method and System for Extending Spatial Wavenumber Spectrum Of Seismic Wavefields On Land Or Water Bottom Using Rotational Motion

摘要

The present invention provides extensions to the sampled spatial wavenumber spectrum of a seismic wavefield on the free surface of the earth or at the bottom of a body of water to wavenumbers higher than the Nyquist limit for the physical layout spacing of the seismic sensor units. The seismic sensor units are comprised of linear sensing elements for at least linear vertical particle motion; and rotational sensing elements for rotational motion around at least one, or more, horizontal axes. Stress and wavefield conditions known on the land surface of the earth or on a water bottom allow the rotational sensing element to yield the transverse horizontal gradient of the vertical particle motion wavefield. This horizontal gradient and the linear vertical particle motion data are utilized in techniques of sample reconstruction to yield an improved horizontal spatial sampling of the linear vertical particle motion wavefield. These reconstructed seismic wavefield samples represent spatial wavenumbers beyond the basic spatial Nyquist limit when using only linear sensors for the seismic sensor unit spacing employed. The method has a wide range of application in seismic surveys for oil and gas exploration and production, and for other purposes.