A Worldwide Review Update of Reinjection in Geothermal Fields

Abstract

Reinjection plays an essential role in maintaining sustainable development and management of geothermal resources. This paper presents an updated review of the worldwide experience of reinjection in electric-power producing geothermal fields. Information from ~150 geothermal fields were used to investigate the impact of the main reinjection parameters, such as: reinjection location (infield, outfield, edge-field), reinjection depth relative to production zone (deep, same level, shallow), distance from production wells, reinjection fluid temperature and the amount of reinjection fluid, are taken into consideration. Positive and detrimental effects on the reservoir were assessed by considering the type of geothermal system. The change of reinjection strategy in response to production is also investigated, while keeping in mind the historical information, to reveal the lessons learned from reinjection experiences of various fields. This survey indicates that the dominant production decline mechanism depends on; whether the geothermal system is vapor-dominated, liquid-dominated or hot water. However, the design of reinjection strategy should be site-specific and flexible, as it is likely to change with time due to thermal and chemical breakthrough into production wells, ground inflation and induced; subsidence and seismic activities.