| Title | Reversing carbon emissions in the geothermal energy industry project: A geoscience perspective |
|---|---|
| Authors | E. Kaya, B.Y. Lynne |
| Year | 2023 |
| Conference | New Zealand Geothermal Workshop |
| Keywords | NCG reinjection, CO2 trapping, geothermal reservoirs, fluid-rock interaction, geochemical analysis |
| Abstract | This research aims to help reduce Green House Gas (GHG) emissions by creating processes that will enable trappinggases, especially CO2, in solid form while boosting the fluid production from geothermal resources. This will require characterising the unique geochemical, geological, petrophysical, and fluid dynamic properties to investigate potential mechanisms for trapping GHGs, to allow negativeemission energy generation. CO2 entrapment is favoured when there are significant quantities of available cations for chemical and mineralogical reactions to take place. We will build a pressure chamber to conduct laboratory experiments on typical Taupo Volcanic Zone geothermal host rocks placed inside the chamber. The novel part of this programme involves an approach based on injecting chemical agents into the pressure chamber to increase the quantity of available cations, which will encourage permanent entrapment of GHG. The availability of reactive surface areas is also an important control of chemical and mineralogical reactions. Rock characteristics, such as textures, voids, crystal size, and shape, all play a role in enhancing or inhibiting reactions. We will assess the suitability of various TVZ host rocks for GHG entrapment. The programme involves an innovative multistep process designed to document the elemental composition, textural characteristics, and mineralogy of rocks pre-, during, and post-pressure chamber conditions. Laboratory analyses will include X-Ray Diffraction, Scanning Electron Microscopy, Energy Dispersive Spectroscopy, Computerised Tomography, and chamber fluid analyses. This will enable the most suitable TVZ Formations to be targeted for our field trials and determine the optimal chemical agents required for injection that will favour permanent GHG entrapment. The programme is further supported by modelling the predictive behaviour of chemical reactions based on our laboratory results and field trials. As our programme advances during field trials, we plan to monitor the GHG storage capability of various TVZ rock formations. |