With the shale gas revolution helping the U.S. move past Russia and Saudi Arabia to become the world’s largest oil and natural gas producer, more companies are turning to Am Law 100 firms for counsel on major M&A deals as they seek to consolidate market share.

The Williams Companies, a major pipeline operator, has now turned to Gibson, Dunn & Crutcher to advise on a $5.99 billion deal that will create one of the largest U.S. transporters of oil and gas. Tulsa-based Williams announced over the weekend its all-cash bid to take control of Access Midstream Partners, a natural gas drilling company owned by Global Infrastructure Partners (GIP), a New York-based infrastructure fund manager.