ExxonMobil Corp.'s first post-moratorium deepwater exploration well in the Gulf of Mexico (GOM) is proving to be a keeper, with two "major" oil discoveries, as well as a natural gas find, the supermajor said last week.

The discoveries were made in Keathley Canyon (KC), an offshore area that is proving its worth time and again.

"We estimate a recoverable resource of more than 700 million boe combined in our Keathley Canyon blocks," said ExxonMobil Exploration Co. President Steve Greenlee. "This is one of the largest discoveries in the Gulf of Mexico in the last decade."

Early last year ExxonMobil and its partners encountered oil and natural gas at the Hadrian North prospect in KC 919, which extended into KC 918. The exploration wells indicated more than 550 feet of net oil pay and a minor amount of gas in Pliocene and Upper Miocene sandstone reservoirs.

However, after the federal government last year imposed a deepwater drilling moratorium, the well development stalled (see NGI, May 31, 2010). ExxonMobil applied to restart its operations after the moratorium was lifted and in March, within days of receiving permit approval, the company began drilling the Hadrian 5 exploration well (see NGI, May 2; March 28).

The KC 919-3 wildcat well, which is in about 7,000 feet of water, confirmed the presence of a second oil accumulation in the prospect, with more than 475 feet of net oil pay and again a minor amount of gas, the producer stated. The well, which is continuing to drill deeper, is 250 miles southwest of New Orleans.

ExxonMobil in 2009 had encountered 200 feet of natural gas pay in the KC 964 well, which is in Pliocene sandstone reservoirs at its Hadrian South prospect. More than 85% of the resource discovered at the Hadrian North prospect is oil with "additional upside potential," Greenlee noted.

"We plan to work with our joint venture partners and other lessees in the area to determine the best way to safely develop these resources as rapidly as possible," he said.

The Irving, TX-based supermajor operates and has a half-interest in KC 918, KC 919, KC 963 and KC 964. Petrobras America Inc. holds the remaining stake in KC 918. Eni Petroleum US LLC and Petrobras America each hold a 25% interest in KC 919, KC 963 and KC 964.

BP plc, which held around 550 leases in the GOM in late 2009, continues to be the largest leaseholder and one of the leading explorers. It too has encountered success in Keathley Canyon, as have other producers.

In September 2009 BP reported a "giant" discovery at its Tiber prospect in Keathley Canyon, its second major find after the Kaskida discovery (see NGI, Sept. 7, 2009). The Tiber well was drilled to a total depth of 35,055 feet (10,685 meters), "making it one of the deepest wells ever drilled by the oil and gas industry," BP said.

Other successful prospectors to date in Keathley Canyon include Chevron Corp., which earlier this year gained approval to drill a new well in Block 736 in 6,750 feet of water. Initial drilling on Chevron's Well No.1 in Keathley had begun in March 2010 but also was halted following the Macondo well blowout.

Also being watched by industry observers are the Lucius and Buckskin prospects in Keathley Canyon.

In early 2009 Chevron said the Buckskin No. 1 discovery well, in about 7,000 feet of water in KC 872, encountered 300 feet of net pay (see NGI, Feb. 9, 2009). Later that year Anadarko Petroleum Corp. and its partners said the Lucius discovery in Block 875 had encountered more than 200 feet of net pay (see NGI, Dec. 14, 2009). Lucius is nearest to ExxonMobil's latest discovery.

©Copyright 2011 Intelligence Press Inc. All rights reserved. The preceding news report may not be republished or redistributed, in whole or in part, in any form, without prior written consent of Intelligence Press, Inc.