The Lone Star State accounted for more than 70% of US shale output in 2008. Shale gas makes up 20% of the US supply of natural gas, up from 1% in 2000. Some believe it could exceed 50% by 2030.

Currently, Texas’ largest natural-gas producing area is the Barnett Shale in North Texas. The Shale begins west of Dallas, and the city of Fort Worth sits right on top of it. In fact, Fort Worth is the site of the largest urban gas drilling operations in the nation.

As recently as two years ago, there were no significant natural gas reserves in South Texas. However, the Eagle Ford Shale is rapidly developing into a major field and “bringing billions of dollars of household earnings and tens of thousands of new jobs through direct expenditures on drilling and related multipliers,” according to a report by PricewaterhouseCoopers.

The Eagle Ford Shale stretches across several counties including those surrounding Bexar County, where San Antonio is located. While other major shale plays in the US – Barnett in North Texas, Haynesville in East Texas/Louisiana and Marcellus in the Northeast – primarily produce natural gas and condensate, the Eagle Ford Shale is a hybrid: it produces oil in addition to natural gas and condensate.

Energy experts expect the Eagle Ford Shale play to emerge as a major oil and gas producing field in the US over the next decade. EOG Resources, one of largest players in the Eagle Ford Shale, has estimated the Shale, as an oil discovery alone, will rank sixth in size among the all- time giant oil fields in the US - just after the Bakken Shale, according to the PWC report.

The Eagle Ford Shale is expected to attract huge investments over the next decade. In fact, the eight major energy companies in the play plan to spend over $1 billion this year and plan to drill approximately 230 wells in 2010, according to PWC.

According to the Texas Rail Road Commission, there were 231 permitted wells and 123 drilled wells in slated for the Eagle Ford Shale as of April 16, 2010. Experts expect activity to continue to increase over the next few years.

Much of the drilling activity will be directed from office buildings in and around San Antonio. Earlier this month, for example, Chesapeake Operating, Inc. leased 19,652 square feet of class A office space at 4350 Lockhill-Selma Rd in Shavano Park, a San Antonio suburb. The Oklahoma City-based energy firm signed a medium-term lease and will move into its new space in early 2011.

“Chesapeake has significant business in Eagle Ford Shale,” Schnittger tells GlobeSt.com. “San Antonio is the closest place for these companies to set up offices.”

Local real estate experts say Houston-based EOG Resources Inc. recently inked a lease for 86,000 square feet in Tesoro Corp.’s newly completed headquarters building here. Although the company’s local real estate broker declined to discuss the deal, the company’s financial filings with the SEC allude to the fact that it recently opened a San Antonio office. Similarly, BP has entered the San Antonio market – its exploration division leased 16,400 square feet in McAllister Plaza.

“Whether the oil and gas sector will ever be as large a driver for the San Antonio economy as the big three – tourism, medical and military – it certainly will increase as the activity in the Eagle Ford Shale increases,” says Peter Hosey, a partner in the San Antonio office of Jackson Walker LLP who specializes in real estate and energy.

Hosey tells GlobeSt.com the Eagle Ford Shale impact has so far been limited to increasing personal wealth. “A lot of the ranchers who were barely hanging on are now getting $5,000 bonuses per month because of the oil and gas leases they’ve signed,” he explains. “That money is trickling into the economy as these people buy things and spend their bonuses.”

However, Hosey believes the larger impact is just now beginning as the major energy firms begin to drill in the Shale. In addition to the office space many of the firms have leased in San Antonio, he believes the companies that support the drilling industry – surveyors, environmental firms, general contractors and heavy machinery suppliers – will see their business pick up.

“We hope other oil and gas related companies will do business down here and need some office space,” Schnittger says. “We hope the Eagle Ford Shale will continue to be a driver, both for the economy and the overall office market.”