Abstract

Since Indonesian Independence in 1945, proved ultimately recoverable petroleum resources in the Republic of Indonesia have quadrupled from approximately 12 BBOE to nearly 50 BBOE, with over 800 new fields having been discovered in fourteen principal areas. Over one-third of post-independence reserve additions have come from newly productive petroleum systems. In recent years, exploration has continued to be rewarding with an average of two significant discoveries per year exceeding a reserve size of 50 MMBOE.

Indonesia has over twenty producing petroleum systems which yield a variety of exploration statistics and discovery process curves. Three basic patterns in the discovery process curves are recognized. The classic upwardly convex curve reflects the effect of early exploration efficiency linked to geologic controls; this pattern is particularly well displayed in areas such as Central Sumatra and Salawati. Other areas such as East Java show an inverted or concave upward curve, caused partly by an economically driven late surge in large reserve additions, linked to developing gas markets. A random or straight line discovery process is apparent in West Natuna, where a more complex petroleum system has inhibited exploration efficiency to date.

Examination of past exploration statistics and patterns can serve as a useful guide for assessing and ranking remaining opportunities in mature areas, and can also provide models for resource assessment and exploration strategy applicable to newly emerging frontier areas.