| Title | Understanding mineralogical and geochemical evolution in geothermal reservoirs through reactive transport modelling |
|---|---|
| Authors | D.E. Altar, S.J. Zarrouk, E. Kaya |
| Year | 2023 |
| Conference | New Zealand Geothermal Workshop |
| Keywords | Reactive transport simulation, Fluidrock interaction, Natural state reservoir model, TOUGHREACT™ |
| Abstract | Reactive transport modelling plays a crucial role in unravelling the dynamics of geothermal reservoirs as they evolve over time. By utilising these models, we gain a deeper understanding of the temporal progression of mineral alteration and its influence on the reservoir’s characteristics. This information empowers us to effectively manage and safeguard these valuable resources while offering critical insights into sustainable development. This study was designed to understand the mineralogical and geochemical evolutionary process of conventional geothermal reservoirs. An idealised 3D large-scale numerical model was set up to comply with the prevailing conditions in a two-phase-liquid-dominated geothermal reservoir. The models were established to assess the long-term fluid and rock interaction in geothermal systems and gain insights into the hydrothermally altered rocks. The results of our reactive transport modelling study provide information about the deep geochemical processes that occur during fluid circulation within the reservoir. The model captures the natural processes that alter the chemical composition of minerals in the reservoir over time, highlighting spatial mineral alteration patterns, their impact on porosity and permeability, and how these factors influence flow paths. Additionally, the study investigates the mineralogical and geochemical changes induced by the influx of CO2, H2S and H2. The model also explores the effects of fluid chemistry and geologic structures on underground fluid circulation. |