Factors to watch in evaluating oil and gas reserves.

• Price changes can increase or decrease reserves
• Improved technologies can increase the reserves
• New discoveries can increase the reserves. Elsewhere there are studies that predict what is left to be discovered.
• Political realities can increase but more frequently decrease reserves.

So reserves is an economic concept unlike the size of the total resource which is a geological concept and the technically recoverable portion of the total resource which is an engineering concept. These three concepts and the quantification that corresponds to each concept has a relationship which is not always as clear as it should be and ofttimes controversial especially when things are changing rapidly.

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