Deepwater Gulf of Mexico, USA: Miocene Regional Play Fairway Mapping

Charles Oliver and Robert A. Sullivan
Devon Energy Corporation, Houston, TX

In anticipation of what were expected to be highly competitive Central Gulf of Mexico lease sales in 2007 and 2008, the regional team within Devon Energy’s Gulf of Mexico Exploration group undertook a study in 2005 to establish a regional structural and sequence stratigraphic framework for the Miocene age section in the Deepwater Gulf of Mexico.

A detailed sequence stratigraphic interpretation of over 140 available wells logs was undertaken. The study utilized paleontological data, facies stacking patterns, global sea level curves and lithological markers to create a temporal framework for the seismic interpretation. For every well, the gross interval, net sand, and sand percentage for each sequence was recorded. Utilizing the sequence stratigraphic framework and a combination of 3D prestack depth and time seismic data, the regional team mapped the Upper, Middle, and Lower Miocene where possible. The seismic data were also used to interpret the ascension zones from the autochthonous Jurassic salt, allochthonous salt bodies, salt sutures, and the subsalt truncations of time equivalent surfaces to create salt architecture maps through time. Combining the net sand, salt architecture, and Miocene isochore maps with petroleum system data enabled the creation of “play fairway” maps to help focus Devon’s exploration efforts and to evaluate leased acreage for farm-in opportunities.

With recent major oil discoveries such as Big Foot and Knotty Head and with the price of oil approaching $100 per barrel, Lease Sale 205 generated over $5 Billion in bids on 723 blocks from 84 companies. This study is currently being updated to incorporate additional wells and seismic data to focus on Lease Sale 206 in March, 2008.

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