Publications

The future of large very mature oil fields relies upon the successful application of EOR techniques. This paper discusses a pilot application of air injection in a water flooded reservoir in the Handil field as a tertiary recovery technique.The Handil field, a large and complex fluvio-deltaic type oil field, is located in the Mahakam Delta, Indonesia. This currently very mature field has been developed using conventional oil recovery methods: natural depletion and peripheral water injection and produced a maximum of 200,000 BOPD in the late 70s. Currently, the oil recovery is around 55% with a 15,000 BOPD daily production at high water cut.In 1995, injection of lean gas as a tertiary recovery technique was successfully started and resulted in a substantial change in the field decline. Opportunities to further extent the project seem, however, limited as the gas is exportable. Air injection as a substitute was evaluated and concluded a promising alternative. As a tertiary recovery technique, air injection is still little applied, demonstration of the applicability of this technique on water flooded reservoirs will allow a much wider application of the air injection technique.A pilot project involving 5 wells was initiated in mid 2001. Encouraging results were obtained but the injection was temporary suspended after 6 months injection due to corrosion problems in the injector well. This first phase resulted in significant reservoir re-pressurization and a success of starting reservoir ignition as proven by the increasing temperature in the air injector well.Key elements for successful implementation of an EOR technique are integrated studies providing in depth understanding of the EOR mechanisms and close reservoir monitoring to follow the reservoir behaviour in detail. For the Handil Air injection project, laboratory experiments, comprehensive studies with compositional and thermal reservoir simulation software and an intensive reservoir monitoring plan were combined to achieve this understanding. Air injection was resumed recently on this pilot project with first results expected soon.