The Eagle Ford Shale oil field had an $87 billion impact across South Texas last year, according to the University of Texas at San Antonio (UTSA), the Houston Chronicle reported.

The university’s latest report on the oil boom, released Tuesday, shows that South Texas’ traditional ranching, farming and hunting economy is increasingly eclipsed by the region’s sudden reinvention as an oil field.

The study calculated the direct economic impacts of oil and gas exploration, as well as the so-called indirect and “induced” economic activity created from things such as suppliers building warehouses or workers spending their paychecks.

UTSA looked at 15 of the busiest counties in the Eagle Ford region.

The study takes the first stab at trying to count the number of RV parks and worker camps, known more commonly as “man camps,” that have appeared in South Texas.

UTSA counted 320 RV parks and worker camps with 7,600 units. There were an estimated 50 RV parks just in the city of Three Rivers.

Man camps and RV parks to house workers sprouted virtually overnight a few years ago when the sudden drilling activity filled up all the local hotel rooms in the region. They’re everywhere, but hard to count.