Todd Culwell, a partner in Pillsbury Winthrop Shaw Pittman in Houston, says his firm has done a considerable amount of domestic and international energy work for Tokyo-based Marubeni Corp., but he led the team that negotiated the Japanese company’s first foray into U.S. shale plays.

On April 5, Marubeni Denver Julesberg LLC, a subsidiary of Marubeni Corp., and Marathon Oil Corp. of Houston announced an agreement for Marubeni to buy an interest in Marathon’s ownership in the Niobrara shale play in the DJ Basin in Wyoming and Colorado.