Lower Tertiary Discoveries in the Gulf of Mexico Deepwater: Capitalizing on Success

Greg Kelleher and Ken Beeney
Devon Energy Corporation, Houston, TX

Devon's exposure to the Gulf of Mexico began in 1999 with the acquisition of PennzEnergy and continued with the acquisition of SFS in 2000. The company drilled a limited number of exploration tests; mostly amplitude-supported stratigraphic traps with limited success.

In 2002, Devon made a strategic decision to emphasize impact exploration in the deepwater GOM. A four-year look back of Devon's GOM exploration results indicated higher success rates were obtained by focusing on large, well-imaged structural traps. To this end, Devon participated in the Cascade prospect, a large salt cored 4-way structure, with a primary objective in the Miocene.

After encountering wet Miocene sands, Cascade was drilled deeper and established a significant hydrocarbon column in the lower Tertiary Eocene and Paleocene section. In order to capitalize on this trend-opening discovery, Devon entered into a joint venture gaining access to additional acreage and opportunities including 2 geologically similar discoveries in Walker Ridge. Devon's strategy also involved establishing internal expertise, acquiring extensive 3D data and targeting lease sale opportunities on un-leased structures. The 2003 Ocean Energy merger also increased our acreage in the trend.

Results of this strategy to date include interest in 4 lower Tertiary discoveries, an inventory of more than 20 prospects, an impressive leasehold position, and the most extensive database of any operator in this new trend. Public data released to date suggests the emerging lower Tertiary trend extends from Alaminos Canyon through Walker Ridge and provenance studies indicate multiple source points for sediment input.

AAPG Search and Discovery Article #90039©2005 AAPG Calgary, Alberta, June 16-19, 2005