Mitsui will earn approximately 100,000 net acres in exchange for funding 100% of Anadarko’s share of development costs in 2010, and 90% of these costs thereafter, with an estimated completion of all obligations by 2013.

In addition, Mitsui will have the opportunity to purchase a 32.5% share of Anadarko’s existing wells and additional acreage acquisitions by reimbursing a proportionate share of Anadarko’s prior expenditures, currently estimated to be approximately $100m.

Jim Hackett, chairman and CEO of Anadarko, said: “We are very pleased to have Mitsui as a partner in the Marcellus shale. This transaction reflects the significant value of Anadarko’s fairway position in the Marcellus shale, which has a gross unrisked resource potential of more than 30Tcf (trillion cubic feet) of natural gas and spans more than 715,000 gross acres.

“We continue to ramp up our activities in the Marcellus and anticipate drilling more than 4,500 wells over the coming years. We have successfully partnered with Mitsui in other parts of the world and look forward to working with them and our other partners in the Marcellus, as we continue to develop and deliver these domestically produced, clean-burning natural gas resources to American consumers.”

The JV agreement is effective from January 1, 2010. Closing of the transaction is subject to applicable regulatory approvals and other contractual conditions, and is anticipated on March 15, 2010.