Structural interpretation from horizontal seismic sections

Abstract

The interpreter of a 3-D survey must utilize a data volume. Horizontal slices through a data volume, called Seiscrop™ sections, have unique properties and structural interpretation from them is fast, convenient, and effective. An event on a Seiscrop section displays local strike, a property which permits direct contouring of a structural surface without any timing and posting. The width of an event on a Seiscrop section is a composition of the frequency of the data and the structural dip. Event terminations indicate faults or other discontinuities when they are transverse to structural strike. Faults parallel to structural strike are much less evident on a single Seiscrop section but become apparent with the relative movement of events from section to section. In practical mapping, the interpreter normally contours one fault block before proceeding to the next with the correlation between them being established from the vertical sections. With dual polarity variable area displays, the interpreter can perceive five amplitude levels and normally picks the edge of a trough. With color amplitude Seiscrop sections, it is possible to pick on the crest of any event. With color phase sections, the interpreter can pick at any arbitrary but consistent point on the seismic waveform. The horizontal perspective often permits the interpreter to recognize subtle structural features which might have gone unnoticed if studying the prospect from vertical sections alone.