Reinjection in geothermal fields − A worldwide review update

Abstract

Reinjection is very important for all types geothermal reservoirs under production and it can become the key factor in the success or failure of the geothermal power development. This work gives an up-to-date description and analysis of worldwide experience of reinjection in geothermal reservoirs to provide guidelines for the optimum implementation of reinjection.In 2011, Kaya et al. [1] conducted a review of worldwide experiences of injection in geothermal fields, based on published information from 91 electric-power producing geothermal developments. In the present review, we have extended the database to 126 geothermal developments and added an additional five years of reported field experience. This updated review, investigates past and current reinjection strategies implemented in the geothermal fields and the response of different types of geothermal reservoirs to these strategies.The location of reinjection wells and the amount of reinjected fluid, in addition to problems, adverse effects and benefits associated with production, have been taken into consideration. This study shows that the design of reinjection is most often empirical and site-specific, because the effect of injection on production depends on the setting of the given geothermal system. However, there are some generic similarities depending on whether the system is vapour-dominated, liquid dominated, or hot-water. Experience has shown that reinjection should be planned as early as possible in the field development process and it should be flexible, as it is likely to change with time. An optimum reinjection strategy should balance the requirements of sustaining the reservoir pressure and preventing early thermal breakthrough of reinjected water. The effects of reinjection on the natural hot recharge and, therefore, on energy recovery from the system may also be important.