Use of Horizontal Seismic Sections to Identify Subtle Traps

Abstract

A three-dimensional seismic survey, after proper design, data collection and data processing, yields a three-dimensionally migrated data volume. Horizontal, or SeiscropTM, sections sliced from this data volume provide a direct horizontal view of the subsurface from which structural interpretation can be very straightforward. In the absence of structure, Seiscrop sections display stratigraphic or paleogeomorphic features directly. However, structural deformation can be removed from the data by flattening. Horizon Seiscrop sections, sliced from the flattened volume, permit stratigraphic and other depositional features to be recognized and studied in detail without the confusion of structure. We have used three-dimensional seismic data from the Gulf of Thailand area in which many lateral stratigraphic changes are known to occur. We have studied the stratigraphic variations at several levels and have inferred the existence of a number of subtle features including bars and channels. Seiscrop sections and horizon Seiscrop sections both displaying seismic amplitude have been augmented by the equivalent sections displaying velocity. These were sliced from a volume of seismic logs derived from the seismic traces by the G-LOGTM process.