scholarly journals The characterisation of an exhumed high-temperature paleo-geothermal system on Terre-de-Haut Island (the Les Saintes archipelago, Guadeloupe) in terms of clay minerals and petrophysics

2019 ◽  
Vol 7 (1) ◽  
Author(s):  
Gildas Beauchamps ◽  
Béatrice Ledésert ◽  
Ronan Hébert ◽  
Vivien Navelot ◽  
Alexiane Favier
Keyword(s):  
High Temperature ◽  
Clay Minerals ◽  
Geothermal System ◽  
Les Saintes

scholarly journals Numerical Study on Damage Zones Induced by Excavation and Ventilation in a High-Temperature Tunnel at Depth

Energies ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4773
Author(s):  
Jianyu Li ◽  
Hong Li ◽  
Zheming Zhu ◽  
Ye Tao ◽  
Chun’an Tang
Keyword(s):  
High Temperature ◽  
Lateral Pressure ◽  
Numerical Study ◽  
Pressure Coefficient ◽  
Fracture Morphology ◽  
In Situ Stress ◽  
Surrounding Rock ◽  
Geothermal System ◽  
Mechanical Coupling ◽  
Lateral Pressure Coefficient

Geothermal power is being regarded as depending on techniques derived from hydrocarbon production in worldwide current strategy. However, it has artificially been developed far less than its natural potentials due to technical restrictions. This paper introduces the Enhanced Geothermal System based on Excavation (EGS-E), which is an innovative scheme of geothermal energy extraction. Then, based on cohesion-weakening-friction-strengthening model (CWFS) and literature investigation of granite test at high temperature, the initiation, propagation of excavation damaged zones (EDZs) under unloading and the EDZs scale in EGS-E closed to hydrostatic pressure state is studied. Finally, we have a discussion about the further evolution of surrounding rock stress and EDZs during ventilation is studied by thermal-mechanical coupling. The results show that the influence of high temperature damage on the mechanical parameters of granite should be considered; Lateral pressure coefficient affects the fracture morphology and scale of tunnel surrounding rock, and EDZs area is larger when the lateral pressure coefficient is 1.0 or 1.2; Ventilation of high temperature and high in-situ stress tunnel have a significant effect on the EDZs scale; Additional tensile stress is generated in the shallow of tunnel surrounding rock, and the compressive stress concentration transfers to the deep. EDZs experiences three expansion stages of slow, rapid and deceleration with cooling time, and the thermal insulation layer prolongs the slow growth stage.

scholarly journals Gas emissions and crustal deformation from the Krýsuvík high temperature geothermal system, Iceland

2020 ◽  
Vol 391 ◽  
pp. 106350 ◽  
Author(s):  
Sylvía Rakel Gudjónsdóttir ◽  
Evgenia Ilyinskaya ◽  
Sigrún Hreinsdóttir ◽  
Baldur Bergsson ◽  
Melissa Anne Pfeffer ◽  
...  
Keyword(s):  
High Temperature ◽  
Crustal Deformation ◽  
Geothermal System ◽  
Gas Emissions

scholarly journals Geomagnetic Survey to Explore High-Temperature Geothermal System in Blawan-Ijen, East Java, Indonesia

2018 ◽  
Vol 31 ◽  
pp. 02003 ◽  
Author(s):  
Yunus Daud ◽  
Syamsu Rosid ◽  
Fikri Fahmi ◽  
Faris Maulana Yunus ◽  
Reza Muflihendri
Keyword(s):  
High Temperature ◽  
Magnetic Anomaly ◽  
Volcanic Rocks ◽  
Hydrothermal Activity ◽  
Geothermal System ◽  
Geothermal Area ◽  
Variation Reduction ◽  
Geomagnetic Survey ◽  
Surface Alteration ◽  
Steep Topography

Ijen geothermal area is high-temperature geothermal system located in Bondowoso regency, East Java. It is categorized as caldera-hosted geothermal system which is covered by quaternary andesitic volcanic rocks with steep topography at the surrounding. Several surface thermal manifestations are found, such as altered rocks near Mt. Kukusan and a group of Blawan hotsprings in the northern part of the caldera. Geomagnetic survey was conducted at 72 stations which is distributed inside the caldera to delineate the existence of hydrothermal activity. Magnetic anomaly was obtained by reducing total magnetic measured on the field by IGRF and diurnal variation. Reduction to pole (RTP) method was applied with geomagnetic inclination of about -32°. In general, the result shows that high magnetic anomaly is distributed at the boundary of study area, while low magnetic anomaly is observed in the centre. The low anomaly indicates demagnetized rock that probably caused by hydrothermal activity. It has a good correlation with surface alteration observed close to Mt. Kukusan as well as high temperature reservoir drilled in the centre of caldera. Accordingly, the low magnetic anomaly also presents the possibility of geothermal reservoir in Ijen geothermal area.

scholarly journals Hydrogeochemical Characteristics and Genesis of Geothermal Water from the Ganzi Geothermal Field, Eastern Tibetan Plateau

Water ◽  
2019 ◽  
Vol 11 (8) ◽  
pp. 1631
Author(s):  
Fan ◽  
Pang ◽  
Liao ◽  
Tian ◽  
Hao ◽  
...  
Keyword(s):  
High Temperature ◽  
Tibetan Plateau ◽  
Heat Source ◽  
Chloride Concentration ◽  
Geothermal Field ◽  
Geothermal Water ◽  
Helium Isotope ◽  
Geothermal System ◽  
The Tibetan Plateau ◽  
Geothermal Waters

The Ganzi geothermal field, located in the eastern sector of the Himalayan geothermal belt, is full of high-temperature surface manifestations. However, the geothermal potential has not been assessed so far. The hydrochemical and gas isotopic characteristics have been investigated in this study to determine the geochemical processes involved in the formation of the geothermal water. On the basis of δ18O and δD values, the geothermal waters originate from snow and glacier melt water. The water chemistry type is dominated by HCO3-Na, which is mainly derived from water-CO2-silicate interactions, as also indicated by the 87Sr/86Sr ratios (0.714098–0.716888). Based on Cl-enthalpy mixing model, the chloride concentration of the deep geothermal fluid is 37 mg/L, which is lower than that of the existing magmatic heat source area. The estimated reservoir temperature ranges from 180–210 °C. Carbon isotope data demonstrate that the CO2 mainly originates from marine limestone metamorphism, with a fraction of 74–86%. The helium isotope ratio is 0.17–0.39 Ra, indicating that the He mainly comes from atmospheric and crustal sources, and no more than 5% comes from a mantle source. According to this evidence, we propose that there is no magmatic heat source below the Ganzi geothermal field, making it a distinctive type of high-temperature geothermal system on the Tibetan Plateau.

Geophysical investigations of the Cove Fort‐Sulphurdale geothermal system, Utah

Geophysics ◽  
1985 ◽  
Vol 50 (11) ◽  
pp. 1732-1745 ◽  
Author(s):  
Howard P. Ross ◽  
Joseph N. Moore
Keyword(s):  
High Temperature ◽  
Large Scale ◽  
Thermal Anomaly ◽  
Power Production ◽  
Time Frame ◽  
Geothermal Reservoir ◽  
Magnetic Data ◽  
Geothermal System ◽  
Thermal Anomalies ◽  
Geothermal Fluids

The Cove Fort‐Sulphurdale KGRA is part of one of the largest thermal anomalies in the western United States. Since 1975 an extensive data base has been developed which includes the results of detailed and regional geologic, gravity, magnetic, seismic, and resistivity investigations. Geologic studies have delineated the major tectonic elements of the thermal system and have led to the recognition of large‐scale gravitational glide blocks that act as a leaky cap to portions of the geothermal system. Gravity and magnetic data have delineated major throughgoing structures beneath alluvium and basalt cover, and have indicated the importance of the Cove Fort‐Beaver graben in localizing the geothermal reservoir. The presence of these structures and a high level of microearthquake activity suggest other target areas within the larger thermal anomaly. Electrical resistivity surveys and thermal gradient holes both contribute to the delineation of the known reservoir. Four deep exploration wells which test the geothermal system were drilled between 1975 and 1979. One well, CFSU 42–7, recorded temperatures of 178°C. The high cost of drilling, high corrosion rates, low reservoir pressures, and the apparent limited extent of the high‐temperature reservoir led to a premature conclusion in 1980 that the field was not economic for large‐scale electric power production. More recent drilling in the vicinity of CFSU 42–7 resulted in the discovery of high‐temperature (200°C?) geothermal fluids at a depth of approximately 350 m. A well‐head generator was installed and power production is expected in 1985. Additional development of the geothermal reservoir is anticipated in the 1985 to 1987 time frame.

Heat transfer estimation through a high-temperature geothermal field in New Zealand quantified by multi-channel data modelling

2021 ◽  
Author(s):  
Alberto Ardid ◽  
Rosalind Archer ◽  
David Dempsey
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
High Temperature ◽  
New Zealand ◽  
Geothermal Field ◽  
Heat Fluxes ◽  
Geothermal System ◽  
Geothermal Systems ◽  
Total Heat Flow ◽  
Sustainable Resource Management

<p>In high-temperature geothermal systems, understanding heat transfer helps conceptualize the whole system as well as estimating the resource size. To obtain the fullest picture, it is necessary to integrate different types of data, e.g., surface electromagnetic surveys, wellbore lithology, geochemistry, and temperature logs. This can be achieved through joint modelling. Here, we quantify the spatial distribution of heat transfer through the hydrothermally-altered, impermeable smectite layer that has developed atop the Wairākei-Tauhara geothermal system, New Zealand. Our approach involves first constraining 1D magnetotelluric (MT) inversion models with methylene blue analysis (MeB, an indicator of conductive smectite clay) and mapping these onto temperature and lithology data from geothermal wells. Then, one-dimensional models of heat transfer are fitted to well temperature logs to estimate heat flux variations across the field. We use our integrated method to estimate the average heat flux through the clay cap (2.2 W/m2) and total heat flow (380 ± 21 MW) of the Wairākei-Tauhara geothermal field. This approach models multiple datasets for estimating heat fluxes and could be applied in geothermal provinces around the world with implications for sustainable resource management and our understanding of magmatic systems.</p>

Exploring geothermal resources using active and passive EM methods in the coastal areas of volcanic islands

2021 ◽  
Author(s):  
Simon Védrine ◽  
Pascal Tarits ◽  
Mathieu Darnet ◽  
François Bretaudeau ◽  
Sophie Hautot
Keyword(s):  
High Temperature ◽  
Geothermal Field ◽  
Coastal Areas ◽  
Geothermal System ◽  
Geothermal Resources ◽  
Geothermal Exploration ◽  
Near Surface ◽  
Urbanized Areas ◽  
Transient Electromagnetism ◽  
Volcanic Islands

<p>Electromagnetic geophysical exploration plays a key role in high-temperature geothermal projects to estimate the geothermal potential of a region. The objective of an EM campaign applied to high-temperature geothermal exploration is to obtain an image of the impermeable clay cap, the permeable geothermal reservoir, and the system's heat source at depth, as these three components of the overall geothermal system have distinct electrical signatures. However, deep electromagnetic imaging in the coastal areas of volcanic islands represents a major challenge due to the presence of strong cultural noise induced by urbanized areas concentrated around the coast, the proximity to the sea, strong variations of topography and bathymetry, the small size of targets and the heterogeneity of the near surface. Our objective is the multi-scale integration of airborne transient electromagnetism (ATEM), shallow marine and in land magnetotelluric (MT) and controlled source electromagnetism (CSEM) to improve the reconstruction of deep geological structures by inversion. The contribution of the CSEM method is the key to overcoming cultural electromagnetic noise and exploiting data acquired in urbanized areas. In order to study how to integrate the different EM data, we first apply our methodology to data from a geothermal exploration campaign carried out a few years ago in Martinique in the French West Indies. Then, we present results from runs with synthetic tests for a campaign planned this year in Guadeloupe, also in the French West Indie, whose objective is to increase the production capacity of an existing geothermal field.</p>

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