Anadarko Petroleum (APC), along with its partners, announced today that it has encountered a very promising oil formation in the Gulf of Mexico at its Shenandoah-2 well. The test well tapped a formation with more than 1,000 feet of economically producible hydrocarbons, and according to Anadarko's vice president of deepwater and international exploration, it's "one of the largest discoveries in the Gulf of Mexico". The Shenandoah-2 well was drilled to a total depth of 31,400 feet.

This is the second well drilled in Walker Ridge block 52. Back in 2009, the first Shenandoah well tapped a formation with about 300 feet of economically producible hydrocarbons. Today's discovery was located about 1 mile southwest of the previous discovery and about 1,700 feet further down. 

Anadarko is the operator of the two discovery wells and has a 30% ownership in the play. Anadarko and its partners -- ConocoPhillips (COP 0.10%) (30% ownership), Cobalt International Energy (NYSE: CIE) (20%), Venari Resources (10%), and Marathon Oil (MRO 0.11%) (10%) -- all plan to continue evaluating the prospects of the Shenandoah field.