Norphlet Aeolian Dunes in the Deepwater Gulf of Mexico

Theodore Godo¹, Joris Grimbergen¹, Tom Walker², John Wagner², Steve Gabay², and Laurens Gaarenstroom^1
1 Shell Exploration and Production Company, Houston, TX
² Nexen Petroleum USA, Inc, Dallas, TX

The prolific Norphlet Aeolian sand play, sealed and sourced by the basal Smackover, has been exploited for its oil and gas reserves in a trend that extends from Jackson, Mississippi to the Florida panhandle. This trend includes the coastal waters of Alabama at the Mobile Bay fields. The trend was explored offshore Florida during the mid 1980's and early 1990's but developments were hampered by marginal economics and environmental concerns. The last federal lease sale in this latter area was held in 1988.

In December 2001, federal lease sale 181 opened a small area of the eastern gulf comprising 256 OCS blocks in the Desoto Canyon and Lloyd Ridge protraction areas. In anticipation of this sale, regional geologic and geophysical interpretations indicated that Norphlet Aeolian sands would very likely occur in the northern portion of the sale 181 area. Prospect Shiloh was mapped outboard of the Cretaceous shelf/Florida escarpment edge in 7500 feet of water. Shiloh's exploration targets were stacked Jurassic aged objectives of Cotton Valley, Haynesville and Norphlet Formations in a simple dip closure.

This presentation will focus on the characteristics of the Norphlet oil discovery at Shiloh and its impact on the regional understanding of this play. A Norphlet whole core was found to be entirely composed of an Aeolian dune complex with better porosity than fields in Mobile Bay. Detailed petrography revealed interesting similarities and differences with other segments of this play. Verification of the Norphlet presence, quality and charge in the deep water has opened up a new play in the GOM. Further exploration in Desoto Canyon is planned for 2006.