Selim S. Shaker¹
(1) Phillips Petroleum Company, Bartelsville, OK

Abstract: Trap integrity: An exploration risk in deep water enclosed mini-salt basins in the Gulf Of Mexico

In the Gulf of Mexico, several ponded, salt-rooted mini-basins have attracted exploration endeavors. Keathley Canyon Block 255 Well #1 (total depth of 21,550 feet) has unsuccessfully tested one of these basins.

Integrating the geopressure profile of this well with the stratigraphic column and the structural setting of the basin demonstrate inadequate seals. Analyses of the Repeat Formation Tester data and the conventional wire line logs on KC255 #1 confirm the incompetence of these seals. The possible causes of the low retention capacity for commercial hydrocarbon entrapments include:

• The shift of lithostatic gradient to the sea floor in deep water reduces the sediment column retention capacity envelope.
• The lithology is rich with sand facies with possible coarser sections at the deeper part of the well. This type of deposit retards disequilibrium compaction.
• Salt wall drag, with possible associated faults along the periphery, cause a pressure differential between the depocenter and the rim. This might be responsible for hydrocarbon breaching along the high points on the structure.

Pressure profiles assessment in frontier plays is an essential tool to evaluate trap integrity, seal capacity, and quantifying reserves

AAPG Search and Discovery Article #90914©2000 AAPG Annual Convention, New Orleans, Louisiana