Introduction to Seismic Reflection Imaging: Pt 2 FIELD GEOMETRY FOR MULTICHANNEL SEISMIC (MCS) PROFILES
Layouts for • a comon-shot gather; • a cmmon mid-point gather; and • a common receiver gather.
Sequence of survey layouts to acquire a 6-fold coverage; S indicates the source and G a geophone (or hydrophone). Fold = N/2n where N = total number of receiver groups; n = number of group intervals moved between shots
Results of common mid-point (CMP) stacks showing improvement in imaging for summations of 6, 18 and 48 shot-receiver pairs.
Composite shallow reflection record made up of five separate 12-channel records, each of which was recorded with a different time delay between the shot instant and the start of recording. • Corresponding time-distance graph identifying the major seismic events on the record. The optimum window is that range of source-receiver separations that allows the target reflection to be observed without interference from other events.
The application of a time-varying gain function to a waveform exhibiting spherical divergence, in order to recover signal amplitudes at later travel times. Gain functions are applied in discrete windows(labelled 1 to 5 as shown).
Types of filters: (A) bandpass; (B) low-cut (high-pass); (C) high-cut (low-pass); (D) notch.