Multicomponent OBS and VC acquisition for wavefield reconstruction

Abstract

In ocean‐bottom seismic (OBS) and vertical‐cable (VC) surveying, receiver stations are stationary on the sea floor while a source vessel shoots on a predetermined x ‐ y grid on the sea surface. To reduce exploration cost, the shot point interval often is so coarse that the data recorded at a given receiver station are undersampled and thus irrecoverably aliased. However, when the pressure field and its x‐ and y‐derivatives are measured in the water column, the non‐aliased pressure field can be reconstructed by interpolation. Likewise, if the vertical component of the particle velocity (or acceleration) and its x‐ and y‐derivatives are measured, then also this component can be reconstructed by interpolation. The interpolation scheme can be any scheme that reconstructs the field from its sampled values and sampled derivatives. In the case that the two field's first‐order derivatives are recorded the number of components are six. When also their second‐order derivatives are measured, the number of components is ten. The properly interpolated measurements of pressure and vertical component of particle velocity from the multicomponent measurements allow proper up/down wavefield decomposition, or deghosting. New wavefield reconstruction methods as those suggested here are of significant interest since, presently, the seismic industry is in the process of developing multicomponent cables or streamers, and is in the process of carrying out research on new multicomponent sensors.