There are numerous examples of wells that are produced from a profitable, well-known zone to generate cash flow and then re-entered to explore the potential of new lower or higher zones that have demonstrated promise during drilling and testing. Naturally, production on the higher zone is temporarily stopped to allow drilling and logging tools through.

However, if you insist on simplicity in a complex world, I'll certainly be glad to leave you to your own devices in future. I'm outa here until the quality of postings becomes a little more informative and less loaded by brothers-in-law.