Monitoring of Icelandic Geothermal Fields During Production

Abstract

The energy resources of geothermal systems are known to be limited and their development can be compared to mining. The rate of energy extraction during utilization will normally greatly exceed their natural replenishment. This causes pressure draw-down with subsequent cooling in some cases or changes in production characteristics. Monitoring of production response parameters and chemical composition of the geothermal fluids is an important tool in the management of geothermal fields. The production response data are the necessary basis for reservoir modeling and simulation of the response to different production rates. Chemical monitoring may give a warning before actual cooling or changes in production characteristics occur. During the last decade increasing efforts have been made to establish effective monitoring systems for the geothermal fields utilized in Iceland. A data network for monitoring production response data in low temperature geothermal fields is currently being expanded. Chemical monitoring has been effected in most high temperature geothermal fields from the beginning of utilization and is gradually coming into use in the low temperature geothermal fields. The usefulness of monitoring has been amply demonstrated in both high temperature and low temperature geothermal development by the discovery of production problems and prevention of trouble.