Term used in oil and gas for describing a well where information is to be kept secret. Only people in the know are to hear or see information. Can also be used in everyday speech as something to keep secret between a group of people.
Term used in the Oil and Gas Industry describing a well where no information is to get out. Info is only shared between the most trusted people. Can be used in everyday speech for a deadly secret that others are not to repeat and you would only tell a spouse or old friend.