Conquering the ultra-deep

Although exploration in the US GoM has extended well beyond the mile-deep mark, technical problems posed by these water depths and the distance from existing infrastructure make development of ultra-deep discoveries complex and costly. Energy companies are pushing technology to the limit and combining capital and human resources to improve the economics of marginal ultra-deep fields. Anne Feltus reports

SHELL SET the pace in the Gulf of Mexico's (GoM) ultra-deep-water when it began producing from the 0.72 trillion cubic feet (cf) Mensa gasfield in mid-1997. On Mississippi Canyon Block 686, about 140 miles southeast of New Orleans, Mensa was the first field development to boast a subsea completion in waters deeper than a mile. In recent years, almost two dozen other discoveries have been announced in the ultra-deep Gulf, which, by US Minerals Management Service standards, starts at 5,000 feet. However, production has been initiated from only one other project - Horn Mountain, another field in the Mississippi Canyon area that holds an estimated 150m barrels of oil equivalent (boe) in recovera