McALLEN -- The oil and gas rush in South Texas' Eagle Ford Shale region is supporting 116,000 jobs, many in counties that just five years ago were fighting population loss, according to a university study released Tuesday.The University of Texas at San Antonio's Institute for Economic Development presented its second annual report on the Eagle Ford Shale's economic impact to legislators in Austin.In 2011, the same study found that the oil and gas drilled from the belt of South Texas ranchlands supported about 48,000 jobs in drilling, support operations, pipeline construction, refineries and petrochemicals. The economic impact from one year to the next similarly increased to $61 billion last year from $25 billion the year before in the 20 counties studied."I didn't expect to see the ramp-up so quickly in terms of the actual jobs in 2012 versus 2011," said the study's lead investigator, Thomas Tunstall, the director of the UTSA Center for Business and Community Research. "We knew a lot of these things were on the way and would start to make an impact, but I frankly thought it would be more gradual just because I thought it would take longer to get things in place."But when the production data is considered, it's clear that the workforce must have grown dramatically.Oil production from 2011 to 2012 nearly tripled from 126,000 barrels per day to 352,000 barrels, Tunstall said. And nearly 3,000 new wells were drilled last year in the energy-rich shale band that stretches northeast from Laredo.The study was funded by America's Natural Gas Alliance, a trade group representing natural gas and exploration companies.The activity has been a boon for rural counties that have experienced the energy industry's boom and bust cycle before, but also for metropolitan areas such as San Antonio and Corpus Christi.The 2011 study showed much of what was coming and 2012 confirmed that much has happened.The pipeline infrastructure to handle new wells continues to grow, as do processing and refining facilities.Small South Texas towns were suddenly awash in budget surpluses, but also facing increased demands to improve infrastructure stressed by the explosive growth.Researchers found that local governments received more than $1 billion in total revenue from the oil-and-gas-related business in 2012, while the state collected $1.2 billion.Last year's dizzying growth rate is expected to level off in coming years, reaching $89 billion of economic impact and supporting 127,000 jobs in 2022, according to the study.