Geochemistry of geothermal fluid with implications on circulation and evolution in Fengshun-Tangkeng geothermal field, South China

Geothermics ◽  
2022 ◽  
Vol 100 ◽  
pp. 102323
Author(s):  
Ji Luo ◽  
Yiman Li ◽  
Jiao Tian ◽  
Yuanzhi Cheng ◽  
Zhonghe Pang ◽  
...  
2020 ◽  
Author(s):  
Paolo Basile ◽  
Roberto Brogi ◽  
Favaro Lorenzo ◽  
Tiziana Mazzoni

<p><span><span>Social consensus is a </span><span>condition precedent for any intervention having an impact on the territory, such as geothermal power plants. Therefore, private investors studied and proposed innovative solution for the exploitation of the medium enthalpy geothermal resource, with “zero emissions” in atmosphere, with the target of minimizing its environmental impact. “Montenero” project, developed by GESTO Italia, complies with this precondition.</span></span></p><p><span><span>The area covered b</span><span>y the exploration and exploitation permit is located on the northern edge of the great geothermal anomaly of Mt. Amiata (Tuscany), about 10 km north of the geothermal field of Bagnore, included in the homonymous Concession of Enel Green Power.</span></span></p><p><span><span>The geological - structural setting of the area around the inactive volc</span><span>ano of Mt. Amiata has been characterized by researches for the geothermal field of Bagnore, carried out by Enel Green Power over the years. The geothermal reservoir is present in the limestone and evaporitic rocks of the “Falda Toscana”, below which stands the Metamorphic Basement, as testified by the wells of geothermal field of Bagnore. The foreseen reservoir temperature at the target depth of 1.800 m is 140 °C, with an incondensable gas content of 1,8% by weight.</span></span></p><p><span><span>The project was presented to the authorities in 2013 and it is </span><span>now undergoing exploitation authorization and features the construction of a 5 MW ORC (Organic Ranking Circle) binary power plant. The plant is fed by three production wells for a total mass flow rate of 700 t/h. The geothermal fluid is pumped by three ESPs (Electrical Submersible Pump) keeping the geothermal fluid in liquid state from the extraction through the heat exchangers to its final reinjection three wells.</span></span></p><p><span><span>The reinjection temperature is 70 °C and the circuit pressure is maintained above the </span><span>incondensable gas bubble pressure, i.e. 40 bar, condition which prevents also the formation of calcium carbonate scaling. The confinement of the geothermal fluid in a “closed loop system” is an important advantage from the environmental point of view: possible pollutants presented inside the geothermal fluid are not released into the environment and are directly reinjected in geothermal reservoir.</span></span></p><p><span><span>The </span><span>environmental authorization procedure (obtained) has taken into account all the environmental aspects concerning the natural matrices (air, water, ground, ...) potentially affected by the activities needed for the development, construction and operation of “Montenero” ORC geothermal power plant. A numerical modeling was designed and applied in order to estimate the effect of the cultivation activity and to assess the reinjection overpressure (seismic effect evaluation). The project also follows the “best practices” implemented in Italy by the “Guidelines for the usage of medium and high enthalpy geothermal resources” prepared in cooperation between the Ministry of Economic Development and the Ministry of the Environment.</span></span></p>


2004 ◽  
Vol 36 (3) ◽  
pp. 1224
Author(s):  
Π. Κάρμης ◽  
Γ. Βαργεμέζης ◽  
Η. Παπαδόπουλος ◽  
Π. Τσούρλος

In this work we examine the potential of the time-domain electromagnetic method (Transient EM) in the exploration of geothermal field and the study of the geological environment. The method was applied in the geothermal field of Aristino (Alexandroupolis), westwards of the Traianoupolis, where the known hot springs exist. The EM method and more specifically magnetotellurics (MT), it has been applied in the past in Greece by various researchers, but it is the first time the TEM method is applied for geothermal exploration purposes. As it has been shown by previous works, in the wider region of Aristino an important geothermal field is developed, with geothermal fluid temperature of 30°-90° and high content of dissolved salts of 10gr/lt. These factors result to the appearance of highly conductive geoelectrical anomalies which are directly related to the geothermal field. The existence of two drillholes in the region allowed the calibration and the control of the effectiveness of the TEM method. The geophysical survey has delimited the area of local geothermal interest that is formed by hot aquifer at a relatively shallow depth, extended North of Aristino and between the main faults of the region. The two main faults are responsible for the creation of a tectonic graben in the intermediary region and the development of a highly conductive formation which correlates well with the hot aquifer tank. The geothermal fluid circulates through the faulting system having high temperature caused by the contact with magmatic masses. The application of TEM proved the operational advantages of the method in the geothermal field exploration. The relatively limited number of TEM soundings presented here does not allow the export of safe conclusions regarding the geothermal field of the wider region, although the evaluation of results based on the geological and geoelectrical data of the region is extremely encouraging and justifies the use of the TEM method in the systematic study and mapping of geothermal fields.


1999 ◽  
Author(s):  
Francesco Di Maria ◽  
Umberto Desideri

Abstract This paper presents a design and off-design study of a geothermal field consisting of a number of wells, a steam network which collects the geothermal fluid, and a power plant to generate electricity. The geothermal field considered is located in Italy and the fluid is a mixture of steam and non-condensable gases. The power plant is a conventional type for vapor dominated fields and has a compressor-extractor to remove non-condensable gases from the condenser. The condenser has wet cooling towers to remove heat. In this study, computer codes developed at the University of Perugia were used to simulate the behavior of geothermal field as a whole. The wells are modeled with second order functions in order to describe pressure-flow rate and temperature-flow rate correlations. The geothermal fluid network is calculated by setting pressures and thermal losses in all the branches. The power plant is simulated with all its components: steam turbine, condenser, gas extractor, cooling towers and auxiliaries. All the components of the geothermal field are simulated at both design and off-design conditions. The fluid network is solved with an algorithm developed by the authors, which allows the definition of boundary conditions by means of curves based on experimental data. The advantage in comparison with conventional techniques, requiring a fixed pressure or flow rate as boundary condition, is that the solution of the network and the power plant is always a real solution. The results show how changes in ambient conditions or in the characteristic curve of one or more plant components may influence power production and the exploitation of the geothermal source.


2020 ◽  
Vol 9 (1) ◽  
pp. 20-25
Author(s):  
Evi Yufita ◽  
Muhammad Isa ◽  
Aztarina Ermy Vijaya

Kandungan senyawa kimia air sangat berguna dalam penentuan karakteristik fluida panas bumi terutama sumbernya dan arah aliran fluida tersebut. Oleh karena itu dilakukan penelitian untuk mengkaji senyawa kimia air yang terkandung pada lapangan panas bumi. Penelitian ini dilakukan dengan metode Titrasi dan Spektrofotometer Serapan Atom (SSA). Pengambilan sampel air dilakukan di dua lokasi mata air panas. Untuk pengujian sampel dilakukan pada Balai Riset dan Standarisasi (Baristan) Banda Aceh. Pengolahan data dilakukan dengan perbandingan kandungan kimia air, sedangkan interpretasi menggunakan diagram segitiga Ternary. Diagram segitiga ini meliputi Cl-SO4-HCO3, digunakan untuk mengetahui kandungan fuida panas bumi, Cl-Li-B digunakan untuk menentukan temperatur suatu lokasi panasbumi dan Na-K-Mg untuk mengetahui kesetimbangan lingkungan fluida panas bumi. Hasil analisis senyawa kimia air menunjukkan bahwa fluida panas bumi memiliki konsentrasi yang didominasi sulfat SO4,  Adapun nilai konsentrasi sulfat masing-masing 95% sampel I dan 97% sampel II. Kandungan kimia air ini diperkirakan berada pada zona upflow. Fluida panas bumi yang muncul ke permukaan dari dua lokasi sampel bersumber langsung dari aktivitas magma. An analysis of the flow of geothermal fluid has been carried out in the Jaboi geothermal field, Sabang. This study aims to obtain a zone of geothermal fluid flow in relation to faults/faults. This research was conducted by the titration method and Atomic Absorption Spectrophotometer (AAS). Sampling was carried out at two hot spring locations, namely crater I and crater IV. For sample testing carried out in a standardized laboratory. Data processing is done through comparison of chemical fluid content and interpretation of Ternary triangle diagrams. The triangle diagram includes Cl-SO4-HCO3, Cl-Li-B and Na-K-Mg to determine the characteristics of geothermal fluids. Based on data that has been processed and correlated with other supporting data (local geological conditions, magnetic, and temperature) shows a relationship that affects each other with the presence of faults. The analysis shows that geothermal fluid in the upflow zone is characterized by a dominant SO4 sulfate concentration (95% for sample I and 97% for sample II). In the Na-K-Mg triangle diagram, the fluid shows an immature water condition because the fluid has mixed with meteoric water. Based on the analysis of the geochemical data of the study area, it was shown that there is a connection with Ceunohot fault trending northeast to southwest as the controller of the flow of geothermal fluid.Keywords: Ternary triangle diagrams, geothermal fluid, chemical water compounds


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