ABSTRACT

Coherence maps, derived from high resolution 3-D seismic data, provide an effective tool for analysis of depositional systems for use as reservoir analog models. Coherence is a post-processing seismic attribute that measures the similarity or dissimilarity of adjacent seismic traces. The intent of this paper is to define the geometry and depositional setting of Pleistocene to Recent deep water sediments deposited in front and behind the Sigsbee Escarpment in southeastern Green Canyon of the Gulf of Mexico (GOM), USA. Bathymetry data and shaded relief maps show this part of the escarpment has 750 m (2500 ft) of relief and appears to be eroded and slumping toward the abyssal plain.

Above the escarpment, sediment appears to be ponded behind a topographic rim created by upwelling of salt around the edge of the escarpment. The fan-shaped sediment behind the rim is interpreted to be a sheet sand approximately 5 km (3 miles) long and 3 km (2 miles) wide. The reservoir analog for this Upper Escarpment Fan Sand is a truncated reservoir within a buried hill, below an erosional unconformity.

In front of the escarpment, on the abyssal plain, we interpret there to be a series of erosional channel surfaces. The channel geometry varies from meandering in the basal part to straighter in the upper section. The channels are 800 m (1/2 mile) wide and 10 to 16 km (6 to 10 miles) long. The reservoir analog for this Basinal Channel Sand is an onlapping reservoir above an unconformity within the escarpment fill section.