The Lower Tertiary Wilcox Trend in the Deepwater Gulf of Mexico

Rains, David B.¹, Larry Zarra², David Meyer² (1) Chevron, Houston, TX (2) Chevron,

Initial Lower Tertiary penetrations in the western deepwater Gulf of Mexico documented a 6,000'+ succession of Wilcox (upper Paleocene – lower Eocene) turbidites located 250 miles down-dip from their fluvial and deltaic equivalents. These same thick turbidites have also been discovered 200 - 300 miles to the east, in new exploration wells in this emerging trend. Regional synthesis demonstrates a systematic progression from lower slope to extensive fan sands, to starved distal basin.

The deepwater Wilcox Trend covers 30,000+ square miles. Well target depths range from 12,000' – 35,000' subsea, water depths range from 4,000' – 10,000', salt canopies vary from 7,000' - >20,000' thick, and cover approximately 90% of the trend. Twenty+ wildcats have been drilled in the Wilcox Trend, with 12 announced discoveries, ranging from 40 – 500 MMboe recoverable reserves. Ultimately, the Wilcox trend has the potential for recovering 3 – 15 bboe reserves from these and additional untested Louann salt-cored structures.

The Jack #2 production test (Walker Ridge 758) had a sustained flow rate over 6,000 bopd from approximately 40% of the reservoir. The test occurred in 7,000' of water and greater than 25,000' subsea, and established six world production test records. Test results significantly increase understanding of trend deliverability.

Many technical challenges need to be resolved to move the billions of barrels of resource trapped in deepwater Wilcox structures to recoverable economic reserves. These challenges include complex sub-salt imaging improvements, reservoir quality, sand distribution, and flow capability, and cost effective drilling and completion, facility, and infrastructure designs.