Heiner Klein¹, Andrew L. Evans²

(1) H.B.K. International Ltd, Bragg Creek, AB
(2) Canadian Hunter Exploration Ltd, Calgary, AB

ABSTRACT: Estimating Exploration Maturity of Basins in Brazil and Argentina

Before entering a new basin an evaluation of its exploration maturity can give valuable insight into how much a particular basin has already been explored and what kind of future discovery sizes can be expected. For each basin, a variety of criteria like prospective basinal area, field size distribution, drilling history and density, creaming curves for reserve additions, production history and future reserve expectations are analyzed. Additionally, factors like number and depth of plays, terrain and water depth are considered.

In Brazil, the onshore Reconcavo basin is an example of a mature basin with limited remaining exploration potential. High depletion rates in fields, lack of significant discoveries for the last 15 years, and declining production are all signs of a mature basin. In contrast, the offshore Campos basin still has considerable exploration potential in Cretaceous-Tertiary turbidites in the deepwater area.

The producing Argentinean basins are in different stages of exploration maturity. The Northwest basin is the least mature, and several recent deep gas discoveries have added significant reserves. The Cuyo and San Jorge basins are mature basins with flattened creaming curves for some 20 years. The Neuquen basin is the most actively explored basin in Argentina. But discoveries in the last 10 years have been only 7 MMboe on average.

None of the individual criteria are conclusive in their own right. However, by looking at different variables and comparing them to the mature Western Canadian basin they form useful tools to rank the exploration maturity of producing basins. This screening then provides valuable guidance for defining a company's entry strategy into a particular country or basin.

AAPG Search and Discovery Article #90906©2001 AAPG Annual Convention, Denver, Colorado