Definition - What does Tight Hole mean?
A Tight Hole is a section of a wellbore where drilling tools with large diameters face resistance. It is basically an open hole. Stabilizers, drill collars, drill pipe, tool joints or parts of a drill string face resistance when a driller drills through a tight hole. Another meaning of a tight hole is a well that is kept secret (with regards to the geological information).
Petropedia explains Tight Hole
In the oil and gas industry, any well is deemed as a tight hole when its drilling data and other drilling parameters are not widely available with the E&P organizations or if it is related to the geometry of the well. The tight hole status is sometimes granted by the states which helps the companies in keeping the information secret with respect to a well. Mostly, the drilling information is not shared just to get a competitive edge over other E&P organizations. This secrecy is related with the benefit that the organization will reap out and thus, the exploration wells are termed or designated as tight holes. The wellbore stability is equal to the sloughing formation, which can cause the conditions for the tight hole.