CHARACTERIZATION OF SEISMIC AMPLITUDE ANOMALIES AT HIBERNIA USING 3D SEISMIC DATA

Abstract

The Chevron et al. Hibernia P-15 well penetrated one of many bright spots and encountered gas. Bright spots are one of four 'direct hydrocarbon indicators' and result from the high acoustic impedance contrast from gas accumulations in Tertiary sediments. Many of these bright spots occur at or near the same stratigraphic level in the South Mara Unit, which is bounded by two main unconformity reflections: the Base Tertiary Unconformity and another regionally extensive unnamed one overlying the South Mara Unit. Paleo-environmental interpretation using seismic and well log data suggests that the P -15 well penetrated a near shore sand body that was preserved during a transgression. The transgression was marked by localized erosion so many other sand units are not preserved. Other bright spots in the South Mara may be the result of tuning effects and may or may not contain any dissolved gas.

Key Words: Bright spots, Direct Hydrocarbon Indicators, Shallow Gas, Jeanne d'Arc Basin