| Title | Mastering Reinjection in the Hellisheidi Field, SW-Iceland: A Story of Successes and Failures |
|---|---|
| Authors | Gunnar Gunnarsson |
| Year | 2011 |
| Conference | Stanford Geothermal Workshop |
| Keywords | reinjection, fractured reservoir, earthquakes, thermo-mechanical coupling. |
| Abstract | Reinjection has posed a major problem in the operation of the Hellisheidi Power Plant, SW-Iceland. The formation temperature at the originally planned reinjection zone proved to be very hot (>300°C) when injection wells were drilled there. In order to be able to use that zone for production a new reinjection zone was planned. The new zone has been promising despite problems in operating the new injection wells. The wells are drilled into a fault that is active and injection tests have resulted in swarms of small earthquakes. The injectivity of the wells in the new reinjection zone is highly dependent on temperature of the reinjected water. This dependence can be explained by thermo-mechanical effects on fractures in the fracture governed reservoir. |