The analysis and interpretation of [[well log|well-log]] data, [[drill stem test|drill-stem tests]], etc. in terms of the nature of the [[formation|formations]] and their fluid content. The objectives of formation evaluation are (1) to ascertain if commercially producible hydrocarbons (or other forms of energy and minerals) are present, (2) to determine the best means for their recovery, and (3) to derive [[lithology]] and other information on formation characteristics for use in further exploration and development.