A petroleum deposit, or several petroleum deposits combined, discovered in the same well, and which testing, sampling or logging have shown probably contain mobile petroleum. The definition covers both commercial and technical discoveries. The discovery receives the status of a field, or becomes part of an existing field when a Plan for Development and Operation (PDO) is approved by the authorities (see Field).

Technical discovery success is the relationship between the number of technical discoveries and the number of wildcat wells. Economic or commercial discovery success is the relationship between the number of discoveries that are developed or are clearly profitable today and the number of wildcat wells.

Description that contains specific information concerning wells and well paths relating to planned drilling and well activities.

Almost pure methane gas, lacking water and with few heavy components.

A well drilled within the proved area of an oil or gas reservoir to the depth of a stratigraphic horizon known to be productive; a well drilled in a proven field for the purpose of completing the desired spacing pattern of production.