A Structural Analysis of the Green Knoll Salt Dome Located in Southeast Green Canyon, Gulf of Mexico
Randy Broussard and Abu Sarwar
The western portion of the Mississippi frontal fold belt in the Gulf of Mexico contains what is known as the Green Knoll Salt Dome. The autochthonous root of the Green Knoll Salt Dome has a salt-cored fold belt 'Frampton anticline' that runs through it. The creation and growth of this salt diapir is punctuated by salt deposition, salt migration, and sediment loading, and is linked to the Frampton fold. An indicator of these growth periods are exhibited in a great angular unconformity (halo-kinetic sequence boundary) that flanks the diapir which occurred during the Pliocene and Miocene chronostratigraphic boundary. The 'Redwood' (GC 1001) prospect was drilled after the discovery of middle and lower Miocene aged sands containing hydrocarbons in the Mad Dog field (GC 826) located about 12 miles northeast of 'Redwood'. The objective Miocene sands in the 'Redwood' borehole were missed by this angular unconformity causing the sands to pinch out. BOEM has provided a Geoframe IESX workstation for the seismic interpretation in conjunction with well log data which was used to discover that the unconformity may not have provided the seal needed to trap hydrocarbons on the flank of the salt dome, even though there are plenty of Cretaceous and Jurassic source rock as well as faulting to provide the migration of hydrocarbons to the trap. Yet, it is still possible that if a well were to be drilled further down dip from where The 'Redwood' prospect was drilled, one may find good quality sands with potential hydrocarbons.
AAPG Search and Discovery Article #90167©2013 GCAGS and GCSSEPM 63rd Annual Convention, New Orleans, Louisiana, October 6-8, 2013