Abstract

The Awibengkok geothermal field, West Java, Indonesia, began generation of 110 MWe in 1994 and will be expanded to 330 MWe by late 1997. Awibengkok is a liquid dominated geothermal resource and consequently a large volume of separated brine must be disposed of to meet environmental requirements. Reservoir modeling studies indicate that injecting brine back into the reservoir can provide pressure support and increase the ultimate energy reserves of the field if properly managed. The current Awibengkok injection strategy involves placing much of the injection across a semi-sealing permeability barrier and placing the remainder deep along the periphery of the field to take advantage of pressure support and minimize undesirable effects on production wells. A field-wide monitoring program has been in place since the start of commercial operation and a combination of chemical sampling and tracer testing have been used to identify flow paths within the reservoir and quantify injectate recovery. This information is being used to optimize current injection operations and to continuously refine the injection strategy for the Awibengkok 330 MWe development.