--> ABSTRACT: Regional Sequence Stratigraphy of Neogene Turbidite Deposits, North - Central Green Canyon and Central Ewing Bank Lease Areas, Gulf of Mexico, by Peter Varnai, Alonso F. Navarro; #91020 (1995).

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Regional Sequence Stratigraphy of Neogene Turbidite Deposits, North - Central Green Canyon and Central Ewing Bank Lease Areas, Gulf of Mexico

Peter Varnai, Alonso F. Navarro

The Plio-Pleistocene turbidite deposits in the north-central Green Canyon lease area are both important petroleum producing reservoirs and a fixture exploration play. The interaction between sedimentation and salt deformation controls the distribution of depositional systems in the intraslope basins. Establishing the regional sequence stratigraphic framework helps to define potential areas for fixture petroleum exploration, and aids structural analysis. Data base consists of 3680 km of 2D multifold seismic profiles, well logs from 50 wells, and biostratigraphic data from 55 wells.

Paleoecologic data and seismic facies interpretation indicate that slope deposition in bathyal water depths was dominant throughout the Neogene in the area. Differences in seismic facies, lithologies and depositional environments indicate four major depositional intervals. The lower Pliocene strata, which include the 4.2 and 3.8 Ma sequences, predominantly consist of sand-rich unchannelized lobe deposits. The upper Pliocene interval comprises four sequences, and is a thin (20-150 meter) condense zone, consisting primarily of shale. Sands (including foraminiferal sands) developed only locally.

The lower Pleistocene interval (1.4, 1.1 and 0.8 Ma sequences) contains predominantly shale-rich turbidites in channel-levee systems. Sands locally developed over the sequence boundaries in unchannelized lobes and in the axial parts of channels. The upper Pleistocene sequences (0.7 Ma and younger) consist of shaley channel-levee systems. Deltaic deposits are present in the northwestern part of the area. Several submarine canyons developed in these sequences in the eastern part of the study area, which fed the western part of the Mississippi Fan channel-levee systems.

Most discoveries in the study area are in braid turbidite systems. Complex salt-related structures enhance the prospectivity of undrilled unchannelized lobe sands and sand-rich channel complexes. Similar reservoirs are expected in sub-salt prospects.

AAPG Search and Discovery Article #91020©1995 AAPG Annual Convention, Houston, Texas, May 5-8, 1995