Portable dense geophone array for shallow and very shallow 3D seismic reflection surveying - Part 1: Data acquisition, quality control, and processing

A strategy is presented for 3D seismic reflection imaging of shallow and very shallow targets, utilizing a portable dense geophone array. A dense 2D geophone array identifies faint shallow reflections and suppresses coherent noise. Fixing the receiver locations enables the design of quality control (QC) procedures that improve event identification. The number of shots, shot locations, and their effect on target illumination can be evaluated with various QC tools during acquisition to improve overall data quality. At the same time the portability of the array increases the cost effectiveness. Radially projected supergathers enable the choice of efficient processing parameters. With sufficiently high fold and 3D frequency-wavenumber filtering, the dense geophone array is shown to image reflectors from 8 to 50 ms, along with a dominant 20-ms water table reflection.