EVALUATION OF LARGE AREAS OF A SEDIMENTARY BASIN

Abstract

A quantitative basis for evaluating exploration acreage can be provided at all stages of petroleum exploration.

Treating each main sedimentary sequence separately, the volume of sediments concerned is calculated or estimated, and factors based on industry experience and personal judgement are applied to this volume of generated, movable, trapped, discoverable, and producible hydrocarbons, expressed as oil.

The present value of these inferred reserves is calculated by assessing the likely profit per barrel (in the local situation) and discounting this over the likely period before half of the reserves are produced.

From the present value, the maximum economic expenditure on land acquisition plus exploration can be indicated.

As exploration proceeds, new information can be used to revise the estimate of inferred reserves and, if the economic environment changes, the current value can also be revised.

Particularly where land acquisition is costly such economic assessment can place proper limits on the price payable for land at all stages of exploration and thus avoid the situation where production success is not followed within a reasonable period by profitability.