• McKelvey’s Box is a simple device/diagram for visualizing categories of oil and mineral reserves and resources that shows level of uncertainty and risk

    • The original McKelvey box (with SPE-AAPG-WPC terminology) shows basic terminology with simple uncertainty grouping
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    • The updated/modern (updated by a joint working group of the SPE, AAPG and WPC), reorganized and subdivided by probabilistic uncertainties (i.e. 1P, 2P, 3P)
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  • It was developed to avoid ambiguity in communication (in reporting of natural resources) and contains the following basic idea

    • only discovered, commercially-viable deposits get to be called Reserves.
    • Discovered but sub-commercial (with today’s technology and pricing) are contingent resources.
    • Potentially producible and viable deposits that we’ve not yet found are called prospective resources. These are important distinctions, especially if you are a public company or a government.