Oil well builder Frontier Energy Group LLC announced Monday that it had purchased business rival Canary Wellhead Equipment Inc. The move typifies recent consolidation in the domestic oil-field services sector.

The closely kept Frontier Energy did not reveal the terms of the deal, but CEO Dan Eberhart said his Denver-based company is buying privately held Canary for less than $100 million. Canary constructs parts used in oil production and offers wellhead services.

"A lot of companies have grown up with the shale revolution," Eberhart said. "What you're seeing is small to medium-size companies gobbling up mom-and-pop companies."

Acquiring Oklahoma City-based Canary could help Frontier expand its operations to promising new drilling sites in Oklahoma, Kansas and Ohio. Currently, much of Frontier's activity centers on the Bakken Shale play in North Dakota.

Experts predict consolidations will continue as the oil and natural gas boom in the United States fuels a supply glut and low prices.

"This is a period of retrenchment in the industry," said Simmons & Co. International analyst Bill Herbert. "There are too many startups. That process has run its course" (Ben Lefebvre, Wall Street Journal, Jan. 14). -- BS