David,
Depends on what part of Zavala County you are in. Not saying more of the area won’t be developed but bulk of the activity is in the southern portion of the County. Global Geophysical is trying to lease for a large seismic study in Frio/Zavala County, I’m waiting for their terms. If you’re uncertain about your address being correct with the County Clerk I would recommend going to Crystal and trying to get that fixed. I’ve sent letters and been in twice and found out this week that the clerk still hasn’t corrected my address.