Washington has lifted its moratorium, enacted after BP's Deepwater Horizon rig caught fire and sank in April 2010, on oil and natural gas exploration in the Gulf of Mexico.
The U.S. Interior Department is restructuring its departments that oversee offshore work following last year's dismantling of the Minerals Management Services.
Exxon Chief Executive Officer Rex Tillerson told the Platts news service that the approval process for permits for work in the Gulf of Mexico is exceptionally slow but understandable given the post-spill regulatory landscape.
"I think in some respects I have to give them the benefit of the doubt that they are going through a lot of reorganization, they've got a lot of new people coming into the agency that have to be trained," he was quoted as saying. "They're developing a whole new permitting process which we as an industry, and we as an applicant, are having to learn."
Exxon in June announced two major oil discoveries and one natural gas discovery while drilling in 7,000 feet of water south of Louisiana. The recoverable resource potential in the area is more than 700 million barrels of oil equivalent, which Exxon said made it one of the largest discoveries in the Gulf of Mexico in the last decade.