The equity ownership in the company will now be divided between the two existing owners Magellan Midstream Partners (40%) and Plains All American Pipeline (40%), and Anadarko.
Magellan CEO Michael Mears and Plains All American president and CEO Greg Armstrong said: "Magellan and Plains are pleased to have Anadarko as a partner in the Saddlehorn pipeline.
"Anadarko is a committed shipper and has a significant production presence in this region, adding further value to the pipeline project to deliver crude oil to the Cushing hub."
Saddlehorn has been established to construct, own and operate the 550-mile Saddlehorn pipeline.
Magellan will be the construction manager and operator of the pipeline that is estimated to cost $800m to $850m.
The 20in pipeline will transport various grades of crude oil from the DJ Basin, and potentially the broader Rocky Mountain area resource plays, to storage facilities in Cushing, Oklahoma.
Saddlehorn is scheduled to open in 2016. It will have an initial capacity to transport 200,000 barrels per day (bpd), and expand subsequently to an ultimate capacity of up to 400,000 bpd.
