UPDATE, 11/29/12, 5:45, p.m. EST: Information about the lawyers advising on ConocoPhillips’s sale of Kashagan oil field assets to India’s ONGC has been added to the ninth and tenth paragraphs of this story.

Allen & Overy, Borden Ladner GervaisCMS Cameron McKenna, and DLA Piper are the latest firms to reap the benefits from the energy M&A boom.