Houston is home to such well-known oil and gas firms as Halliburton (NYSE:HAL) and ConocoPhillips (NYSE:COP). But you might not know that another handful of companies headquartered in and around the southeast Texas city help to keep the nation's energy wheels turning, even if they're not oilfield services companies per se.

I think Fools should know about two companies occupying this energy periphery: Team (NASDAQ:TISI) and Kirby (NYSE:KEX). Each plays a major role in the refining or transportation of oil, natural gas, or the products made from them, but neither is heavily followed by Wall Street analysts.

First Team first
Let's start with Team. The company is an important player in the oil patch, serving all manner of Big Oil companies, refiners, and pipeline operators. In fact, its services, which fall into such strange-sounding categories as hot tapping, journal turning, and non-destructive testing, all boil down to various forms of piping maintenance and repair.

As you can imagine, that's particularly important to oil and gas pipeline operators, refiners, petrochemical plant operators, and other process industries these days. The company's customers include Big Oil's Chevron (NYSE:CVX), refiner Valero (NYSE:VLO), and a host of energy types in between.

Team, which is actually headquartered in Alvin, Texas, has grown through a combination of organic expansion and acquisition. The company's organic revenue grew by 30% in the May-ended quarter. Team has few rivals; the only company even close to performing its range of services is Dallas-based Furmanite (NYSE:FRM), which is around two-thirds Team's size.

Team's market value is just south of $700 million, which doesn't look particularly out of whack, valuewise, given its PEG ratio of 1.2. Team also sports a solid 23% return on equity, and that metric's come in above 11% in all but one year since 2001.

Kirby won't clean your carpets
And then there Kirby -- a major operator of inland tank barges, which generate slightly more than 80% of its revenue. The company's barges -- the industry's largest such fleet, by far -- are used in concert with its tugs to transport petrochemicals, agricultural chemicals, oil, and refined petroleum products throughout the nation's inland waterways. The company also conducts a diesel-engine service business, which accounts for the remainder of its revenue. This unit provides power and parts for the marine, power-generation, and railroad industries.

Kirby's shares took a tumble this summer, but they're still sitting about 20% higher than a year ago. I consider company's forward P/E below 14, and its PEG ratio below 0.8, cause for optimism. Add in a strong balance sheet, and you may just have another non-energy energy company worth your attention.

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Fool contributor David Lee Smith doesn't have financial positions in any of the companies mentioned above. He does welcome your questions or comments. The Fool has a disclosure policy.