Helix Energy Solutions Group, which has headquarters in Houston, announced it encountered more than 100 feet of oil during drilling operations in the Phoenix field about 93 miles off the coast of Louisiana coast.
The company said the well was drilled to more than 18,000 feet in around 2,300 feet of water in Green Canyon Block 237.
Helix said the well would be developed using a floating production unit. First production from the well is expected by the second quarter of 2013.
In early December, French supermajor Total said it made a "significant" discovery in the North Platte prospect in the Gulf of Mexico. Total said it encountered "several hundred feet of net oil pay" in the region.