For the first seven of its eight years, Burleson grew organically, building a practice by hiring attorneys to serve its oil and gas clients. That strategy shifted in March, when the Houston-based law firm acquired a Denver energy practice, McGloin, Davenport, Severson & Snow. The move added nine attorneys to the firm’s two-year-old Denver office, increasing its size to 41 lawyers.

"We’ve never done such a big acquisition before," said Rick Burleson, who founded the 137-lawyer firm in Houston in 2005. "It was a good opportunity for us."

The Denver acquisition bolstered the firm’s commercial litigation practice, helping to diversify its work for oil and gas companies and provide them with a single source for legal services. "Becoming more and more of a go-to firm in the industry excites me," Burleson said. He said the firm handled about $5 billion in transactions last year.

Last fall, the firm opened a seven-lawyer office in Midland, Texas. Burleson described it as an underserved legal market, noting that half the oil rigs in the United States are in West Texas’ Permian Basin. Attorneys there will offer oil companies services that include litigation, mergers and acquisition work, and oil and gas title work.

That office’s launch followed the 2010 opening of Burleson’s San Antonio office, which came on the heels of the creation of a Pittsburgh office in 2009.

The firm does plenty of oil and gas title work, but its litigators have been busy as well. It represents large oil and gas operators in a very large class action involving leasing issues in the Appalachia region. In Houston, it is counsel for an oil company engaged in a contract dispute with a pipeline company, and in Midland it represents an energy-services company in several injury cases.

Client Kevin Cunningham, general counsel of Cabot Oil & Gas Corp. in Houston, said he likes Burleson’s deep industry knowledge.

"It’s service. It’s depth of experience. It’s focus," he said. The firm is his main source for general energy counsel, title advice, contract drafting and review and regulatory matters. Cunningham is impressed with Burleson’s strategy of opening offices in shale-rich regions, where energy companies extract natural gas using hydraulic-fracturing processes.

"They have followed that advancement in technology to other locales and grown their business on top of that resource," he said. "I don’t know of any other firms that have done that."