Small distance variability

Hello everyone.

I'm doing research on small distance variability between exploration wells. I have all databases, f.e. gamma-ray in every 10 cm depth. What I need to do is to find correlation between two wells. So, my question is which methods should I use? I'm thinking aboout T-test, but maybe it's not proper way to do it. Who did the same research or close to this, please help me with advises or with some usefull information?