Small cap energy play Cluff Natural Resources (CLNR:AIM) gushes 41% higher to 6.3p as an independent audit of its portfolio reveals a big increase in prospective resources.

The CPR or competent person's report shows P50 prospective resources of 2.5 trillion cubic feet (tcf) with 1.73 tcf attributed to its Licence P2248 in the southern North Sea on which a number of different drilling prospects are identified.

CLNRchart

What does this mean? The diagram below shows the different classifications for discovered and undiscovered hydrocarbons.

Reserves

Prospective resources are defined as quantities of oil and gas thought to be recoverable from undiscovered accumulations. The P50 number is also known as the 'best' estimate as opposed to the 'low' and 'high' estimate. These figures will often be based on data from 3D seismic surveys, or results from nearby drilling, and involve a considerable degree of uncertainty.

Once a well has been drilled to test these prospective resources a further audit will typically follow with companies keen to convert prospective resources into reserves.

Cluff is still a long way from this point but these numbers should help with what chairman and chief executive Algy Cluff, a serial entrepreneur in the resources space, describes as the company's 'key focus', attracting the partners and funding so the prospects identified can be appraised.

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Issue Date: 19 Oct 2016