US GULF OF MEXICO Pliocene trend potential in Eastern Garden Banks

Ranking of Pliocene hydrocarbon potential in the eastern Garden Banks area of the US Gulf. Shell's Auger Field development is located north of what could turn into a Pliocene play in the eastern Garden Banks area of the deepwater US Gulf of Mexico. Operators have released very little information about wells drilled into the northern reaches of this trend, and only one well has been drilled to the south. That one well has provided interesting information on just how productive the Pliocene

Jul 1st, 1995

Shell's Auger Field development is located north of what could turn into a Pliocene play in the eastern Garden Banks area of the deepwater US Gulf of Mexico.

Operators have released very little information about wells drilled into the northern reaches of this trend, and only one well has been drilled to the south.

That one well has provided interesting information on just how productive the Pliocene trend might be, the US Minerals Management Service (MMS) claims.

The MMS recently issued a study of the eastern Garden Banks area indicating wide areas of high potential for Pliocene sedimentation and hydrocarbon accumulation in the area.

A total of 36 exploration wells have been drilled in the eastern Garden Banks area, virtually all north of Auger in shallower water. Information has been made available on five of these wells, including Auger.

Garden Banks 568

The latest was BP's well in Garden Banks 568 in water depths over 3,400 ft. The well is east and slightly south of Auger.

The BP well encountered a 3,730-ft-thick Pliocene interval on the way to striking salt at 15,090 ft. Reservoir quality sands ranged in thickness from two ft to 200 ft.

Of the BP well, the MMS study states: "Log characteristics indicate sand deposition occurred in slope/basin-floor fan complexes during the Pliocene. Channel-levee completes, amalgamated channel sands, fan-lobe deposits, and turbidite sheet sands can be identified on well logs. Channels" evidence the existence of a system for transporting sand southward into the undrilled portion of the study area (southeastern Garden Banks).

"The study area is in the deepwater Flexure Production trend that includes Auger Field. Intense salt diapirism during the Pleistocene characterizes the trend.

"Salt structures include shallow, geolgraphically extensive ridges and shallow, isolated piercement diapirs. Interdomal basins contain thick accumulations of Pliocene and Pleistocene sediments."

High Potential

Areas with high potential had:

  1. Wells with reservoir quality Pliocene sands.
  2. Wells with hydrocarbons in Pliocene sediments.
  3. Seismic correlations showing Pliocene sediments at depths of 22,000 ft or less.

Areas with moderate potential included those with:

  1. Wells showing a presence of Pliocene sdeiments.
  2. Seismic correlations indicating Pliocene sediments at depths greater than 22,000 ft.
  3. Lowered confidence level of the seismic correlations in areas of structural complexity.

Based upon information from the BP well, the Auger development, and subsequent studies, the MMS concluded the eastern Garden Banks area has significant acreage with high potential for future hydrocarbon discoveries in Pliocene sediments.

Copyright 1995 Offshore. All Rights Reserved.

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