NDLI: A reactive flow model of the geothermal reservoir Waiwera, New Zealand

Content Provider	Springer Nature Link
Author	Kühn, Michael Stöfen, Heinke
Copyright Year	2004
Abstract	A numerical model of the complex interaction between fluid flow, heat transfer, and chemical reactions of the shallow, coastal, hydrothermal system of Waiwera (New Zealand) is used to test the proposed conceptual model of the field.Due to declining water levels, resulting from over-exploitation during the 1970s, the objective here was to set up a coupled fluid flow and heat transfer model to help in enabling a predictive and sustainable use of the resource. The presented conceptual model of the area is based on hydraulic, thermal, and chemical field observations, which date back as far as 1863. The numerical simulations were carried out with the reactive transport code SHEMAT.The inflow of geothermal water at the bottom of the reservoir prevents seawater from entering the aquifer. If seawater intrusion occurs, it is due to over-exploitation and happens in the upper parts of the aquifer. This is in contrast to common seawater-freshwater interfaces where seawater intrudes at the bottom. The numerical investigations emphasize that, after modifications of the production regime in the late 1980s, the system is recovering again.Additionally, geochemical calculations have been conducted to answer the question if dissolution or precipitation reactions might change the hydraulic properties of the geothermal aquifer. Mixing of fresh, geothermal, and seawater, although each of them in thermodynamic equilibrium with calcite, lead to calcite precipitation or dissolution. Nevertheless, the simulations show that the hydraulic properties of the aquifer are not significantly affected by dissolution or precipitation.Un modèle numérique de l’interaction complexe entre l’écoulement de l’eau, le transfert de chaleur et les réactions chimiques du système hydrothermal côtier peu profond de Waiwera (Nouvelle-Zélande) est utilisé afin de tester le modèle conceptuel. L’objectif est de bâtir un modèle couplé d’écoulement et de transfert de chaleur afin d’encourager une approche prévisioniste et une utilisation durable de la ressource en réponse à des niveaux d’eau en déclin qui résultent d’une surexploitation depuis les années 1970. Le modèle conceptuel présenté est basé sur des observations de terrain concernant l’hydraulique, la température et la composition chimique de l’aquifère, des observations qui peuvent dater d’aussi loin que 1863. Les simulations numériques ont été réalisées avec le modèle de transport SHEMAT. L’entrée d’eau géothermale à la base du réservoir préviens l’intrusion d’eau de mer dans l’aquifère. Si l’intrusion d’eau de mer a lieu, elle est due à la surexploitation qui a lieu dans la partie supérieure de l’aquifère. Cette situation est l’opposée des interfaces eau de mer - eau douce traditionnelles où l’eau de mer pénètre par la base. Les simulations numériques suggèrent que suite aux modifications du régime de production à la fin des années 1980, le système récupère. De plus, des calculs géochimiques ont été effectués afin de répondre à la question à savoir si les réactions de dissolution et de précipitation changent les propriétés hydrauliques de l’aquifère géothermal. Le mélange de l’eau douce, l’eau géothermale et l’eau de mer, même si elle sont tous en équilibre thermodynamique avec la calcite, provoque la dissolution ou précipitation de la calcite. Néanmoins, les simulations montrent que les propriétés hydrauliques de l’aquifère ne sont pas significativement affectées par la dissolution ou la précipitation.Se ha utilizado un modelo numérico de la interacción compleja entre el flujo de fluidos, la transferencia de calor y las reacciones químicas del sistema hidrotermal costero poco profundo de Waiwera (Nueva Zelanda) con el objeto de probar el modelo conceptual del área propuesto. Debido a los niveles de agua decrecientes, el objetivo de este trabajo es establecer un modelo pareado del flujo de aguas y de la transferencia de calor para colaborar en el uso predecible y sostenible del recurso. El modelo conceptual del área presentado está basado en observaciones de terreno hidráulicas, termales y químicas que datan de 1863. Las simulaciones se llevaron a cabo con el código de transporte reactivo SHEMAT. El influjo de agua geotermal al fondo del reservorio impide que el agua de mar entre en el acuífero. Si la intrusión de agua de mar se presenta, esto sucede a causa de la sobreexplotación y ocurre en las partes superiores del acuífero. Esto contrasta con las interfaces comunes de agua de mar-agua dulce donde la intrusión del agua de mar se da al fondo. Las investigaciones numéricas enfatizan que el sistema se está recuperando de nuevo luego de las modificaciones al regimen de producción a fines de los 80. Adicionalmente, los cálculos geoquímicos están dirigidos a contestar si las reacciones de disolución o precipitación pueden cambiar las propiedades hidráulicas del acuífero geotérmico. La mezcla de agua dulce, geotermal y de mar causa precipitación o disolución de calcita a pesar de que cada una de ellas se encuentra en equilibrio termodinámicao con la calcita. Sin embargo, las simulaciones muestran que las propiedades hidráulicas del acuífero no son afectadas siginificativamente por la disolución o precipitación.
Starting Page	606
Ending Page	626
Page Count	21
File Format	PDF
ISSN	14312174
Journal	Hydrogeology Journal
Volume Number	13
Issue Number	4
e-ISSN	14350157
Language	English
Publisher	Springer-Verlag
Publisher Date	2004-08-20
Publisher Institution	International Association of Hydrogeologists
Publisher Place	Berlin, Heidelberg
Access Restriction	One Nation One Subscription (ONOS)
Subject Keyword	Coastal aquifer Conceptual models Numerical modeling Salt-water/fresh-water relations Thermal conditions
Content Type	Text
Resource Type	Article
Subject	Earth and Planetary Sciences Water Science and Technology

Sl.	Authority	Responsibilities	Communication Details
1	Ministry of Education (GoI), Department of Higher Education	Sanctioning Authority	https://www.education.gov.in/ict-initiatives
2	Indian Institute of Technology Kharagpur	Host Institute of the Project: The host institute of the project is responsible for providing infrastructure support and hosting the project	https://www.iitkgp.ac.in
3	National Digital Library of India Office, Indian Institute of Technology Kharagpur	The administrative and infrastructural headquarters of the project	Dr. B. Sutradhar bsutra@ndl.gov.in
4	Project PI / Joint PI	Principal Investigator and Joint Principal Investigators of the project	Dr. B. Sutradhar bsutra@ndl.gov.in Prof. Saswat Chakrabarti will be added soon
5	Website/Portal (Helpdesk)	Queries regarding NDLI and its services	support@ndl.gov.in
6	Contents and Copyright Issues	Queries related to content curation and copyright issues	content@ndl.gov.in
7	National Digital Library of India Club (NDLI Club)	Queries related to NDLI Club formation, support, user awareness program, seminar/symposium, collaboration, social media, promotion, and outreach	clubsupport@ndl.gov.in
8	Digital Preservation Centre (DPC)	Assistance with digitizing and archiving copyright-free printed books	dpc@ndl.gov.in
9	IDR Setup or Support	Queries related to establishment and support of Institutional Digital Repository (IDR) and IDR workshops	idr@ndl.gov.in

Three-dimensional variable-density flow simulation of a coastal aquifer in southern Oahu, Hawaii, USA

Effect of hypersaline cooling canals on aquifer salinization

Numerical simulations to assess thermal potential at Tauranga low-temperature geothermal system, New Zealand

Assessment of water management tools for the geothermal reservoir Waiwera (New Zealand)

Characterization of salt-water intrusion in the lower Esino Valley, Italy using a three-dimensional numerical model

Occurrence of salt water above fresh water in dynamic equilibrium in a coastal groundwater flow system near De Panne, Belgium

Stratigraphic controls on seawater intrusion and implications for groundwater management, Dominguez Gap area of Los Angeles, California, USA

Radial Dupuit interface flow to assess the aquifer storage and recovery potential of saltwater aquifers

Rates of salinization by free convection in high-permeability sediments: insights from numerical modeling and application to the Dutch coastal area

A reactive flow model of the geothermal reservoir Waiwera, New Zealand

Similar Documents

Three-dimensional variable-density flow simulation of a coastal aquifer in southern Oahu, Hawaii, USA

Effect of hypersaline cooling canals on aquifer salinization

Numerical simulations to assess thermal potential at Tauranga low-temperature geothermal system, New Zealand

Assessment of water management tools for the geothermal reservoir Waiwera (New Zealand)

Characterization of salt-water intrusion in the lower Esino Valley, Italy using a three-dimensional numerical model

Occurrence of salt water above fresh water in dynamic equilibrium in a coastal groundwater flow system near De Panne, Belgium

Stratigraphic controls on seawater intrusion and implications for groundwater management, Dominguez Gap area of Los Angeles, California, USA

Radial Dupuit interface flow to assess the aquifer storage and recovery potential of saltwater aquifers

Rates of salinization by free convection in high-permeability sediments: insights from numerical modeling and application to the Dutch coastal area

A reactive flow model of the geothermal reservoir Waiwera, New Zealand