Lower Tertiary Trend: A Study in the Impact of Advancing Technology

Abstract

In 2002, few believed that Lower Tertiary sands would be present, let alone productive. Today these defiant sands are reshaping the industry's appraisal of plays in the Gulf of Mexico (GOM). Back in 2002, supermajor Chevron and independent Devon formed a joint venture to explore and exploit the deep Wilcox formation. According to both, new and emerging technology has been and continues to be the differentiator in both the exploration and exploitation efforts in these deep structural targets and has the potential to create a shock wave on financial portfolios. The Jack-2 well test took place in the second quarter of 2006 at Walker Ridge Block 758 in 7,000 ft of water, and more than 20,000 ft under the seafloor, breaking Chevron's 2004 Tahiti well-test record as the deepest successful well test in the GOM. Chevron, Devon, and Statoil announced that it was a record-setting production test, with the test representing approximately 40% of the total net pay measured in the Jack-2 well. National Geographic recently gave an apt description of industry achievement in the Lower Tertiary trend: "…you're looking at where in the GOM to drill an 80- to 100-million-dollar well that will ultimately be the size of a dinner plate [on the seafloor]." And, according to analysts, it equates to spending U.S. $100 million to drill and construct a well in mile-deep water to as deep as 5.3 miles below sea level beneath a salt canopy. The recent, well-publicized Jack-2 well test is actually the latest of several successes in the play. The Great White and Trident finds by Chevron, located in Alaminos Canyon, were the first, and it is speculated that this trend could extend into the Garden Banks and Green Canyon blocks. "This is truly frontier exploration … pushing boundaries," said Gero Farrugio, Wood Mackenzie Upstream Research Manager for Latin America, the U.S. GOM, and Canada. Other prospects already on record in the GOM Lower Tertiary trend include Cascade in 2002, St. Malo in 2003, the first Jack find in 2004, and Kaskida in 2006. The Jack prospect is located far from any existing platform and pipeline infrastructure. Farrugio points out that while "the Jack-2 test is the first indicator, it is far from proving commerciality of the play." The technology that is being brought to bear to realize the potential of the Lower Tertiary trend is the ingredient that has the potential to bring understanding of this play needed for the creation of infrastructure and ultimately to prove commercial viability. Drilling commenced on the Jack-2 well under 7,000 ft of water and continued to a depth of 28,175 ft. At this depth, pressures can reach 20,000 psi and the temperature of the oil is approximately 200°C.