Triangle and First Reserve will jointly invest about $180 million in the Denver-based limited partnership called Caliber Midstream Partners, Triangle said, with First Reserve to invest $150 million and Triangle to provide the remaining $30 million in equity commitments.
Caliber plans to begin transportation and processing operations in November, with all business lines expected to be in service by August 2013.
North Dakota became the second-largest oil-producing state in the country this year after output from the Bakken and Three Forks prospects surpassed Alaskan production.
Output in the Bakken shale - which spans North Dakota, Montana and Canada - is expected to double to about 1.2 million barrels per day by 2015. Output there was only 6,000 barrels per day six years ago, according to data from North Dakota.
(Reporting by Sakthi Prasad; Editing by Greg Mahlich)