The Inboard Lower Tertiary Play — U.S. GOM Deepwater

Abstract

Abstract

In 2006, the Wilcox play in the Deepwater US Gulf of Mexico was well known, with over 20 wells penetrating the reservoir section and 14 discoveries announced. However, questions of economic viability existed due to concerns over productivity, poor reservoir quality and low API oil. Through regional analysis, Cobalt explorers identified a possible sweet spot for the Wilcox play at the intersection of more deeply buried source rock and an area of implied cooler reservoir due to the presence of a thick allochthonous salt blanket. This ‘inboard’ area (Southern Garden Banks, Northeastern Keathley Canyon, Northwest Walker Ridge and Southwest Green Canyon) was further north than what had been tested to date and largely undrilled, primarily due to poor seismic imaging. It presented a unique opportunity to strategically acquire a position in the US GOM.

The area was characterized by dramatic isopach variations in the Wilcox section due to salt withdrawal, and we hypothesized the possibility of thicker, coarser sands due to ponding in these salt withdrawal minibasins. As well, many identified structures were high relief, and this, in tandem with the thick overlying salt was called upon to provide lower vertical effective stress and thus, improved reservoir quality. Regional mapping and petroleum systems analysis suggested that a lighter oil could be expected in this inboard area due to deeper, longer burial of the source rock section when compared to the outboard areas of southern Walker Ridge.

Cobalt built an initial inventory of 22 prospects from 2006-2009 in the “Inboard Lower Tertiary” play. To date, a total of 12 wells have been drilled by the industry in this part of the Wilcox play, with 4 potentially commercial discoveries. Kaskida, along with Cobalt discoveries at Shenandoah, North Platte and Anchor have a combined expected resource in excess of 1 BBOE. Cobalt and industry continue to mature and test prospects in this evolving play.

AAPG Datapages/Search and Discovery Article #90260 © 2016 AAPG/SEG International Conference & Exhibition, Cancun, Mexico, September 6-9, 2016