Of course it's a joke for some: -
http://www.glossary.oilfield.slb.com/en/Terms.aspx?LookIn=term name&filter=tight hole
2. n. [Drilling]
A well that the operator requires be kept as secret as possible, especially the geologic information. Exploration wells, especially rank wildcats, are often designated as tight. Unfortunately, this designation is of questionable benefit in keeping the data secret.
