Angelina Co., TX mineral lease opportunity

I had a company lease my 100 acres in Angelina county about 10 years ago. The lease amount then was $1500 per acre. There was speculation that a gas well may be in the works behind my property but after the 3 +2 lease was over, nothing happened. I did have a company offer $5000 an acre to buy the Mineral Rights about the same time, but I held out. Hindsight says I should have sold!