Shoot between the group for simulated multichannel processing flexibility
Where standard recording techniques are used it is not uncommon for seismic reflection data to contain undesirable, spatially aliased energy. For conventional recording layouts, the receiver station spacing controls the spatial sampling density so that higher wavenumber definition requires smaller spacing. Selection of the receiver station spacing with a limited number of recording channels is governed by the minimum and maximum offsets required to sample adequately both near-surface and deeper horizons. All too often the shallower reflections, which contain a larger proportion of the shorter wavelengths, are inadequately spatially sampled. But if a relatively small station spacing is chosen then there is insufficient differential moveout for the suppression of multiples by common mid-point stacking. However, if the number of channels is limited, it is still possible to increase the spatial bandwidth by simulating the recording of any integer multiple of the number of channels actually available. The method is appropriate for the acquisition of land data using surface sources because it involves the recording of more than one conventional record on each receiver spread from source positions spaced at equal intervals over one receiver station interval. The individual records for each receiver spread can be interleaved to simulate one field record on a multiple number of channels. This acquisition technique is not a new concept and has been utilised in several countries. However, the full processing potential has not yet been fully realised. In this paper the main recording and pre-stack processing concepts are demonstrated by a series of examples showing data in the time-distance and frequency wavenumber (f-k) domains. A real data set allows comparisons to be made between different processing sequences using this flexible recording method.