Integration of geophysical methods and fractures study for the Vallès geothermal system characterization (NE Spain)

2020 ◽  
Author(s):  
Gemma Mitjanas ◽  
Juanjo Ledo ◽  
Pilar Queralt ◽  
Gemma Alías ◽  
Perla Piña ◽  
...  
Keyword(s):  
Fluid Flow ◽  
Geophysical Methods ◽  
Normal Fault ◽  
Hot Water ◽  
Fault System ◽  
Geothermal System ◽  
Thin Sections ◽  
Main Structure ◽  
Geological Map ◽  
Ne Spain

<p>The Vallès geothermal system is located in the Catalan Coastal Ranges (CCR) (NE Spain). The CCR are formed by horst and graben structures limited by NE-SW and ENE-WSW striking normal faults, developed during the opening of the Valencia Trough (northwestern Mediterranean) (Gaspar-Escribano et al., 2004). In the Vallès Basin area, the thermal anomaly is located in the northeastern horst-graben limit, where a highly fractured Hercynian granodiorite is in contact with Miocene rocks by a major normal fault. This main structure seems to control the heat and the hot-water flow, nevertheless, the geological structure of this area, as well as the role of the Vallès normal fault, is poorly understood.</p><p>Magnetotellurics and gravity methods together with a detailed geological map have been applied in this area to understand the main structure. Although the geophysical part makes up most of the study, we are also elaborating a detailed geological map of the area, making a fractures study at different scales. We are working with DEM alignments analysis, and fractures study from outcrops and thin sections.</p><p>Our preliminary results in gravity show a strong gravity gradient in the NE-SW Vallès half-graben system and the recent MT profiles image the main fault of that system (Vallès normal fault). These results show a basin geometry with the major thickness of the basin towards the depocenter, disagreeing with the roll-over geometry assumed in previous works.</p><p>Interpretations of the fractures study, together with geophysical data and models, have allowed a preliminary characterization of damage zones associated with the fault system, which are directly related to the fluid flow and the hot springs. The nature of this damage zones could be related to relay ramps, commonly regarded as efficient conduits for fluid flow (Fossen and Rotevatn, 2016).</p>

scholarly journals Geothermal resource potential assessment of Erdaobaihe, Changbaishan volcanic field: Constraints from geophysics

2021 ◽  
Vol 13 (1) ◽  
pp. 1053-1063
Author(s):  
Zhi-He Xu ◽  
Zhen-Jun Sun ◽  
Wei Xin ◽  
Liping Zhong
Keyword(s):  
Geophysical Methods ◽  
Close Correlation ◽  
Volcanic Field ◽  
Hot Water ◽  
Geothermal System ◽  
Published Data ◽  
Geothermal Resource ◽  
Geothermal Resources ◽  
Growth Zones ◽  
Geothermal Drilling

Abstract Geothermal resources occurring in the Changbaishan volcanic field are directly or indirectly controlled by volcanic activity and exhibit a close correlation with deep-seated faults. Energy and thermal transfer are generally controlled by groundwater circulation and hot gas emission. This article considers the detectability of hot water and gas by geophysical methods. The controlled source acoustic magnetotelluric (CSAMT) and radon (222Rn) gas methods give straightforward information on electrical resistivity and natural radon emissions, respectively, to assess the geothermal condition. The CSAMT method detected five-banded low-apparent resistivity bodies (decreasing from 3,000 to 300 Ωm), indicating that there exists a high degree of water-bearing capacities in the subsurface. The radon (222Rn) gas concentrations were monitored in two rapid growth zones: one zone showing values ranging from 3,000 to 23,000 Bq/m3, and the other with values from 4,000 to 24,000 Bq/m3. These changes demonstrate that the heat energies available in these areas were very high and that there is potential for geothermal resources in those zones. Combining with previously published data from geothermometry and geothermal drilling, we argue that there is great potential in Erdaobaihe for geothermal exploitation and that the geothermal resource type should be classified into uplift mountain geothermal system no magma type.

scholarly journals Subsurface Structure and Fluid Flow Analysis Using Geophysical Methods in the Geothermal Manifestation Area of Paguyangan, Brebes, Central Java

2016 ◽  
Vol 5 (3) ◽  
pp. 171-177
Author(s):  
Agus Setyawan ◽  
Agnis Triahadini ◽  
Yayan Yuliananto ◽  
Yoga Aribowo ◽  
Dian Agus Widiarso
Keyword(s):  
Fluid Flow ◽  
Surface Temperature ◽  
Hot Spring ◽  
Geophysical Methods ◽  
Depth Interval ◽  
Geothermal System ◽  
Temperature Pattern ◽  
Subsurface Structure ◽  
Central Java ◽  
Manifestation Area

The indication of an active geothermal system is shown by the presence of surface manifestations such as the hot spring in Kedungoleng, Paguyangan, Brebes, Central Java. The temperature of the largest hot spring reaches 74o C and there is an assumption that this is an outflow of Mount Slamet geothermal system. DC-resistivity, Spontaneous Potential (SP) and Shallow Surface Temperature surveys were conducted to determine the subsurface structure as well as its correlation with the distribution of thermal fluid flow and shallow surface temperature. The subsurface resistivity has been investigated using 5 points of the Schlumberger configuration with 400 m separation for each point. For the fluid and temperature pattern, a measurement using 15 m interval in 3 lines of conducting fixed electrode configuration has been carried out, along with a 75 cm of depth of temperature measurement around the manifestation area. The thermal fluid is assumed by the low resistivity of 0.756 to 6.91Ωm and this indicates sandstone that has permeable characteristic. The fluid flows in two layers of Sandstone at more than 10 meter from surface of the first layer. Accordingly, the SP values have a range between -11- 11 mV and a depth interval of 13.42- 28.75 m and the distribution of temperature is between 24o-70oC at a tilting range of 46.06o-12.60o. Hence it can be inferred that the thermal fluid moves in the Northwest direction and is controlled by a fault structure stretching from Northwest to Southeast.Article History: Received Feb 3, 2016; Received in revised form July 11, 2016; Accepted August 13, 2016; Available onlineHow to Cite This Article: Setyawan, A., Triahadini, A., Yuliananto, Y., Aribowo, Y., and Widiarso, D.A. (2016) Subsurface Structure and Fluid Flow Analyses Using Geophysical Methods in Geothermal Manifestation Area of Paguyangan, Brebes, Central Java. Int. Journal of Renewable Energy Development, 5(3), 171-177.http://dx.doi.org/10.14710/ijred.5.3.171-177

Revised hydrogeological model of the hydrothermal system Waiwera (New Zealand)

2021 ◽  
Author(s):  
Andreas Grafe ◽  
Thomas Kempka ◽  
Michael Schneider ◽  
Michael Kühn
Keyword(s):  
Water Management ◽  
New Zealand ◽  
Water Level ◽  
Hot Water ◽  
Hydrogeology Journal ◽  
Natural State ◽  
Geothermal System ◽  
Geological Model ◽  
Species Transport ◽  
Study Region

<p>The geothermal hot water reservoir underlying the coastal township of Waiwera, northern Auckland Region, New Zealand, has been commercially utilized since 1863. The reservoir is complex in nature, as it is controlled by several coupled processes, namely flow, heat transfer and species transport. At the base of the aquifer, geothermal water of around 50°C enters. Meanwhile, freshwater percolates from the west and saltwater penetrates from the sea in the east. Understanding of the system’s dynamics is vital, as decades of unregulated, excessive abstraction resulted in the loss of previously artesian conditions. To protect the reservoir and secure the livelihoods of businesses, a Water Management Plan by The Auckland Regional Council was declared in the 1980s [1]. In attempts to describe the complex dynamics of the reservoir system with the goal of supplementing sustainable decision-making, studies in the past decades have brought forth several predictive models [2]. These models ranged from being purely data driven statistical [3] to fully coupled process simulations [1].<br><br>Our objective was to improve upon previous numerical models by introducing an updated geological model, in which the findings of a recently undertaken field campaign were integrated [4]. A static 2D Model was firstly reconstructed and verified to earlier multivariate regression model results. Furthermore, the model was expanded spatially into the third dimension. In difference to previous models, the influence of basic geologic structures and the sea water level onto the geothermal system are accounted for. Notably, the orientation of dipped horizontal layers as well as major regional faults are implemented from updated field data [4]. Additionally, the model now includes the regional topography extracted from a digital elevation model and further combined with the coastal bathymetry. Parameters relating to the hydrogeological properties of the strata along with the thermophysical properties of water with respect to depth were applied. Lastly, the catchment area and water balance of the study region are considered.<br><br>The simulation results provide new insights on the geothermal reservoir’s natural state. Numerical simulations considering coupled fluid flow as well as heat and species transport have been carried out using the in-house TRANSport Simulation Environment [5], which has been previously verified against different density-driven flow benchmarks [1]. The revised geological model improves the agreement between observations and simulations in view of the timely and spatial development of water level, temperature and species concentrations, and thus enables more reliable predictions required for water management planning.<br><br>[1] Kühn M., Stöfen H. (2005):<br>      Hydrogeology Journal, 13, 606–626,<br>      https://doi.org/10.1007/s10040-004-0377-6<br><br>[2] Kühn M., Altmannsberger C. (2016):<br>      Energy Procedia, 97, 403-410,<br>      https://doi.org/10.1016/j.egypro.2016.10.034<br><br>[3] Kühn M., Schöne T. (2017):<br>      Energy Procedia, 125, 571-579,<br>      https://doi.org/10.1016/j.egypro.2017.08.196<br><br>[4] Präg M., Becker I., Hilgers C., Walter T.R., Kühn M. (2020):<br>      Advances in Geosciences, 54, 165-171,<br>      https://doi.org/10.5194/adgeo-54-165-2020<br><br>[5] Kempka T. (2020):<br>      Adv. Geosci., 54, 67–77,<br>      https://doi.org/10.5194/adgeo-54-67-2020</p>

scholarly journals Geothermal System Study Case near Bucharest

2019 ◽  
Vol 111 ◽  
pp. 06058
Author(s):  
Galina Prică ◽  
Lohengrin Onuțu ◽  
Grațiela Țârlea
Keyword(s):  
Thermal Response ◽  
Hot Water ◽  
Geothermal System ◽  
System Study ◽  
Accurate Calculation ◽  
Good Efficiency ◽  
Efficient System ◽  
One Step ◽  
Study Case ◽  
Geological Formations

The article shows a study case of a geothermal system near Bucharest. In the paper it is shown that for a good efficiency of a geothermal system for heating and air conditioning, it is important to follow a few steps. One step is a very accurate calculation of the heat and cold load. In the next step it is important to use a specific equipment to obtain the Thermal Response Test (TRT) of geological formations crossed by the borehole. TRT is helpful in providing information related to the evolution of the soil temperature while introducing a thermal load. All information that can be obtained or calculated from the TRT will provide how the climate system will function in time and its efficiency. Furthermore, the effective thermal conductivity and thermal resistance of the well will be determined, extremely important parameters in designing the correct length of the geoheat exchanger. The article used specific software to simulate the evolution of parameters in time, for soil and heat pump. Earth Energy Design offer information for the number of needed boreholes, the depth and the yearly evolution of the soil’s temperature in time for the system etc. Following all these main steps, finally a very efficient system can be designed, that can ensure the heating and produce hot water for the consumption of a house, office building or of other destination buildings.

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