A CASE STUDY USING TWO-DIMENSIONAL AND THREE-DIMENSIONAL SEISMIC DATA IN THE HIGH ISLAND AREA, OFFSHORE TEXAS.

A structural seismic interpretation involving twodimensional (2-D) and three-dimensional (3-D) data from the High Island area of offshore Texas reveals significant interpretive advantages in using 3-D seismic mapping techniques. Differences in fault delineation and volumetric calculations are illustrated using color mosaic maps and time slice/vertical section compositions derived through interactive workstation application. Incorporated into the comparison are the following studies: (1) structural mapping of a 2-D grid and a 3-D volume over a common area; (2) calibration of borehole data; (3) measurement of areal extent of anomalous amplitude events associated with hydrocarbon-bearing Pleistocene sands, based on interactive amplitude extraction and interactively derived reflection strength attributesr and (4) amplitude- vs. offset (AVO) calculations of anomalous amplitude events.