Integrated microgravimetric and seismic monitoring approach in the Þeistareykir volcanic geothermal field (North Iceland).

2020 ◽  
Author(s):  
Florian Schäfer ◽  
Philippe Jousset ◽  
Tania Toledo ◽  
Andreas Güntner ◽  
Tilo Schöne ◽  
...  
Keyword(s):  
Geothermal Field ◽  
Hydrothermal Systems ◽  
Earth Tides ◽  
Geothermal System ◽  
Earthquake Activity ◽  
Reservoir Properties ◽  
Geothermal Resources ◽  
Stress Changes ◽  
Geothermal Power ◽  
Ground Motion Records

<p> <span>In volcanic and hydrothermal systems, monitoring of mass and stress changes by continuous gravity field and ground motion records provides information for both volcanic hazard assessment and estimation of geothermal resources. We aim at a better understanding of volcanic and geothermal system processes by addressing mass changes in relation with external influences such as anthropogenic (reservoir exploitation) and natural forcing (local and regional earthquake activity, earth tides). Þeistareykir is a geothermal field located within the Northern Volcanic Zone (NVZ) of Iceland on the Mid-Atlantic Ridge. Geothermal power production started in autumn 2017. For the first time on a geothermal production field, we deployed a network of 4 continuously recording gravity meters (3 superconducting meter, iGrav and one spring gravity meter gPhone) in order to cover the spatial and the temporal changes of gravity and to detect small variations related to the geothermal power plant operation (e.g. extraction and injection). All gravity monitoring stations are equipped with additional instrumentation to measure parameters that may affect the gravity records (e.g. GNSS and hydrometeorological sensors). Additionally, we deployed a temporal seismic network consisting of 14 broadband stations to enhance the seismic activity monitoring of the permanent Icelandic network in this very active region of the NVZ. Results of this unique experiment contribute to determine reservoir properties and main structures and may also reveal details of active tectonic processes. Here, we present the instrumental setup at the site and first results of more than 24 months of continuous gravity and seismicity records.</span></p>

Feasibility, Design and authorization of a zero-emission Geothermal Power Plant in Italy; Case Study: “Montenero” Project

2020 ◽  
Author(s):  
Paolo Basile ◽  
Roberto Brogi ◽  
Favaro Lorenzo ◽  
Tiziana Mazzoni
Keyword(s):  
Power Plant ◽  
Power Plants ◽  
Geothermal Field ◽  
Geothermal Reservoir ◽  
Gas Content ◽  
Geothermal Resources ◽  
Geothermal Fluid ◽  
Geothermal Power Plant ◽  
Green Power ◽  
Geothermal Power

<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>

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>

scholarly journals Geothermal Energy Use and Its Related Technology Development in Japan

2021 ◽  
pp. 1-17
Author(s):  
Kasumi Yasukawa
Keyword(s):  
Power Generation ◽  
Heat Pump ◽  
Research Work ◽  
Hydrothermal Systems ◽  
Ground Source Heat Pump ◽  
Geothermal Resources ◽  
Research Activities ◽  
Ground Source ◽  
Geothermal Power

Abstract Japan has national targets to intensify the geothermal power generation. The government gives several fiscal incentives for geothermal development and R&D through the Ministry of Economy, Trade and Industry. Beside short-termed target by 2030, Japan has a long-term target by 2050. Therefore the R&D also has a short-term target to develop the conventional hydrothermal systems effectively with improved technologies and a long-term target to develop supercritical geothermal resources at a depth of volcanic region. The latter covers from basic scientific investigation to highly technological innovation. In contrast ground source heat pump has been promoted by the private sectors supported mainly by the Ministry of Environment. A topical research work on the ground source heat pump in Japan is suitability mapping for both closed-loop and open-loop systems based on studies on groundwater flows. The detailed situation and research activities for both geothermal power generation and ground source heat pump will be discussed in this paper.

scholarly journals Design of a Small Capacity Geothermal Power Plant for Cooling and Heating Systems of Health Resort in Jordan

2021 ◽  
pp. 14-29
Author(s):  
Omar Othman Badran ◽  
Ghazi Salem Al-Marahleh ◽  
Al- Faroq Omar AlKhawaldeh ◽  
Izzeldeen Abed Aldabaibeh
Keyword(s):  
Power Plant ◽  
Oil And Gas ◽  
Cooling System ◽  
Financial Burden ◽  
Thermal Power ◽  
Geothermal Field ◽  
Health Resort ◽  
Geothermal Resources ◽  
Geothermal Power Plant ◽  
Geothermal Power

Jordan is a developing non-producing oil country; a major part of its needed energy is imported from the neighboring countries in the forms of oil and gas, the cost of this imported energy creates a heavy financial burden on the national economy which reflects on the development plans and the standard living of the people. Jordan has good potential of geothermal energy at different places. Therefore, several applications are suggested to be utilized in the agricultural and industrial fields. In this study the binary thermodynamic cycle is suggested to utilize the geothermal source into the form of power plant for generating electricity for heating and cooling system of a health resort in the nearby region of the geothermal field. Also in this study, the air- conditioning and heating loads for a health resort are calculated and the underground thermal power plant is designed to provide the suitable power supply to the health resort. It is concluded that the geothermal resources of energy is proved to be one of the good options of renewable energy sectors in Jordan. Therefore the geothermal power plant can be an option for electrical production of the Jordanian volcanic mountains resorts.

scholarly journals A comparison of regularized, sharp boundary and tear zone inversions along an MT profile in Sabalan geothermal field, Iran

2020 ◽  
Vol 211 ◽  
pp. 02004
Author(s):  
Mansoure Montahaei ◽  
Saeid Ghanbarifar
Keyword(s):  
Heat Source ◽  
Geothermal Field ◽  
Hydrothermal Systems ◽  
Geothermal System ◽  
Sharp Boundary ◽  
Hypothesis Tests ◽  
Inversion Result ◽  
Inversion Model ◽  
Clay Cap ◽  
Geothermal Region

This paper investigates magnetotelluric (MT) data recorded along a profile in the Sabalan geothermal region, NW of Iran. To find the range of relevant models consistent with the data, this study employed the so-called regularized, tear zone, and sharp boundary inversions. This study could effectively derive three alternative classes of models. Although the models show stable common resistive and conductive features there are some inconsistent details. Unaltered surface rocks and porous Basalt exhibit a high resistive overburden underlain by relatively more conductive Paleozoic sediments. A common signature of hydrothermal systems appears, and resistivities increase beneath a highly conductive clay cap in deeper parts. An intriguing feature resolved in the smoothest inversion model is a second deep conductor of 30 Ωm resistivities at a depth of 3 km, extending close to the surface. It can be related to the hot, solidified volcanic intrusions, resemblingthe heat source in a geothermal system. This study applied the two other inversion approaches for further hypothesis tests. Although the tear zone inversion re-establish the deep conductor (with 38 Ωm resistivities at 3 km depth), it is absent in the sharp boundary inversion result. This study concludes that the second deep conductor has a limited structure resolution.

scholarly journals Aspects of the Chronology, Structure and Thermal History of the Kawerau Geothermal Field

2021 ◽  
Author(s):  
◽  
Sarah Dawn Milicich
Keyword(s):  
New Zealand ◽  
Hydrothermal Alteration ◽  
Electrical Power ◽  
Geothermal Field ◽  
Geothermal System ◽  
Hydrothermal Conditions ◽  
Geothermal Resources ◽  
Textural Characteristic ◽  
Structural Framework ◽  
Geological Conditions

<p>The development and management of high-temperature geothermal resources for electrical power generation requires accurate knowledge of the local geological conditions, particularly where they impact on the hydrology of the resource. This study is an integrated programme of work designed to develop new perspectives on the geological and structural framework of the Kawerau geothermal resource as a sound basis for field management. Although the geological approaches and techniques utilised in this study have previously been used, their application to an integrated study of a geothermal system in New Zealand has not been previously undertaken.  Correlating volcanic and sedimentary stratigraphy in geothermal areas in New Zealand can be challenging due to similarities in lithology and the destruction of distinctive chemical, mineralogical and textural characteristic by hydrothermal alteration. A means to overcoming these issues is to utilise dating to correlate the stratigraphy. Zircons are resistant to the effects of typical hydrothermal conditions and were dated using SIMS techniques (SHRIMP-RG) to retrieve U–Pb ages on zircons. These age data were then used to correlate units across the field, in part aided by correlations to material that had previously been dated from fresh rock by ⁴⁰Ar/³⁹Ar techniques, and used to redefine the stratigraphic framework for the area. [...]  Although previously inferred to be a long–lived system, the modern Kawerau Geothermal Field is a Holocene entity reflecting the rejuvenation of magmatic heat flux associated with Putauaki volcano superimposed on an area of multiple reactivated fault structures, sporadic magmatism and variable rates of subsidence. This study documents past patterns of fluid flow, temperatures and chemistry, and inferred permeability within the field. Using textural relationships in selected samples, the relative timing and patterns of hydrothermal alteration, and fluid flows can be established. These textural relationships are then calibrated against fluid inclusion palaeotemperature measurements and isotope data and related to temperatures and compositions of past fluids. Short–lived heat sources beneath the field resulted from local magma intrusions, and are responsible for the 0.36 Ma and 0.138 Ma rhyolites and Holocene eruptive activity of Putauaki andesite–dacite volcano. The Putauaki activity is inferred to be responsible for the thermal and alteration characteristics of the modern system.</p>

scholarly journals Modelling subsurface geologic structures at the Ikogosi geothermal field, southwestern Nigeria, using gravity, magnetics and seismic interferometry techniques

2019 ◽  
Vol 16 (4) ◽  
pp. 729-741
Author(s):  
Ema M Abraham ◽  
Owens M Alile
Keyword(s):  
Gravity Data ◽  
Geothermal Field ◽  
Seismic Interferometry ◽  
Geothermal System ◽  
Noise Sources ◽  
Southwestern Nigeria ◽  
Geothermal Resources ◽  
Depth Migration ◽  
Passive Seismic ◽  
Resources Exploitation

Abstract We present results and a technique for imaging the subsurface structures of a geothermal field with particular focus on the Ikogosi geothermal field in Nigeria. The intent was to provide an understanding of the subsurface structural setup in the region and assess its viability for further geothermal resources exploitation. High-resolution aeromagnetic and gravity data were used for the study. A constrained 2D forward modelling technique was applied to these datasets to map the shape and corresponding depths of geologic structures in the region. This study has gone deeper to ascertain the basement structure and configurations and how it influences the heat source of the Ikogosi Warm Spring (IWS) region. The dominant host quartzite rock unit at the IWS location reaches average depths of 2.5–3.0 km and is located directly on an intruded high-density geologic formation in the subsurface. Fault structures traversing the IWS source have also been uncovered. We infer that these structural setups are central to the geothermal system of the IWS. Valid reflection responses from the profile model have been retrieved from randomly induced noise sources, using a passive seismic interferometry technique. Pre-stack depth migration of the reflected responses suitably imaged the reflectors within the subsurface of the IWS region, tracing fault boundaries and delineating intruded geological structures. This has provided pre-survey insights into the subsurface seismic imagery of the region. Results derived from this study could assist informed decision making regarding geothermal exploration and exploitation in the region.

Ambient seismic noise monitoring and imaging at the Theistareykir geothermal field (Iceland)

2021 ◽  
Author(s):  
Tania Toledo ◽  
Anne Obermann ◽  
Philippe Jousset ◽  
Arie Verdel ◽  
Joana Martins ◽  
...  
Keyword(s):  
Group Velocity ◽  
Group Velocity Dispersion ◽  
Vertical Component ◽  
Dispersion Curves ◽  
Geothermal Field ◽  
Seismic Network ◽  
Coda Wave ◽  
Underlying Structure ◽  
Geothermal Resources ◽  
Stress Changes

&lt;p&gt;The Theistareykir geothermal field is located at the intersection between the active Northern Rift Zone and the active Tj&amp;#246;rnes Fracture Zone in NE Iceland, and its study is of vital importance for further development of local and regional geothermal resources. Since autumn 2017, a seismic network consisting of 21 stations was deployed to monitor the high temperature Theistareykir geothermal field (Iceland). This seismic network belongs to a set of multiparameter networks installed to better understand the underlying structure and behavior of the geothermal reservoir under exploitation.&lt;/p&gt;&lt;p&gt;In this framework, we use the continuous ambient noise seismic records between October 2017 and October 2019 to compute a 3D shear wave velocity model of the geothermal field and to detect possible stress changes due to the injection and production activities. We compute the phase auto- and cross-correlations of the vertical component recordings, measure the Rayleigh wave group velocity dispersion curves, and obtain 2D group velocity maps between 1 and 5 s.&amp;#160; The 2D group-velocity maps are used to construct regionalized dispersion curves which are then inverted using a Neighborhood Algorithm to retrieve the 3D Vs model of Theistareykir. We observe various underground structures and identify the locations of possible magmatic or hydrothermal bodies in light of available and newly acquired geological and geophysical data. In addition, we analyze the short and long term temporal evolution of the phase auto-correlations using coda wave interferometry and discuss their relationship to the geothermal field operations. We notice a slightly stronger velocity reduction around the production site in comparison to the surrounding regions.&lt;/p&gt;

scholarly journals The EGS Collab Project: An intermediate-scale field test to address enhanced geothermal system challenges

2020 ◽  
Vol 205 ◽  
pp. 01002
Author(s):  
Kneafsey Timothy ◽  
Keyword(s):  
Geothermal Energy ◽  
Crystalline Rock ◽  
Hydrothermal Systems ◽  
Heat Transfer Fluid ◽  
Geothermal System ◽  
Geothermal Systems ◽  
Geothermal Resources ◽  
Intermediate Scale ◽  
Term Extraction

Three components are typically needed to extract geothermal energy from the subsurface: 1. hot rock, 2. a heat transfer fluid, and 3. flow pathways contacting the fluid and the rock. These naturally occur in many locations resulting in hydrothermal systems, however there are enormous regions containing hot rock that do not naturally have adequate fluid, and/or appropriate fluid permeability to allow hot fluid extraction. Some type of engineering or enhancement of these systems would be required to extract the energy. These enormous regions provide the possibility of long-term extraction of significant quantities of energy. Enhanced (or engineered) Geothermal Systems (EGS) are engineered reservoirs created to extract economical amounts of heat from low permeability and/or porosity geothermal resources. There are technological challenges that must be addressed in order to extract the heat. These include proper stimulation, effective monitoring, reservoir control, and reservoir sustainability. The US DOE Geothermal Technologies Office and geothermal agencies from other countries have supported field tests over a range of scales and conditions. A current US field project, the EGS Collab Project, is working nearly a mile deep in crystalline rock at the Sanford Underground Research Facility (SURF) to study rock stimulation under EGS stress conditions. We are creating intermediate-scale (tens of meters) test beds via hydraulic stimulation and are circulating chilled water to model the injection of cooler water into a hot rock which would occur in an EGS, gathering high resolution data to constrain and validate thermal-hydrological-mechanical-chemical (THMC) modeling approaches. These validated approaches would then be used in the DOE’s flagship EGS field laboratory, Frontier Observatory for Research in Geothermal Energy (FORGE) underway in Milford, Utah and in commercial EGS. In the EGS Collab project, numerous stimulations have been performed, characterized, and simulated and long-term flow tests have been completed.

scholarly journals Aspects of the Chronology, Structure and Thermal History of the Kawerau Geothermal Field

2021 ◽  
Author(s):  
◽  
Sarah Dawn Milicich
Keyword(s):  
New Zealand ◽  
Hydrothermal Alteration ◽  
Electrical Power ◽  
Geothermal Field ◽  
Geothermal System ◽  
Hydrothermal Conditions ◽  
Geothermal Resources ◽  
Textural Characteristic ◽  
Structural Framework ◽  
Geological Conditions

<p>The development and management of high-temperature geothermal resources for electrical power generation requires accurate knowledge of the local geological conditions, particularly where they impact on the hydrology of the resource. This study is an integrated programme of work designed to develop new perspectives on the geological and structural framework of the Kawerau geothermal resource as a sound basis for field management. Although the geological approaches and techniques utilised in this study have previously been used, their application to an integrated study of a geothermal system in New Zealand has not been previously undertaken.  Correlating volcanic and sedimentary stratigraphy in geothermal areas in New Zealand can be challenging due to similarities in lithology and the destruction of distinctive chemical, mineralogical and textural characteristic by hydrothermal alteration. A means to overcoming these issues is to utilise dating to correlate the stratigraphy. Zircons are resistant to the effects of typical hydrothermal conditions and were dated using SIMS techniques (SHRIMP-RG) to retrieve U–Pb ages on zircons. These age data were then used to correlate units across the field, in part aided by correlations to material that had previously been dated from fresh rock by ⁴⁰Ar/³⁹Ar techniques, and used to redefine the stratigraphic framework for the area. [...]  Although previously inferred to be a long–lived system, the modern Kawerau Geothermal Field is a Holocene entity reflecting the rejuvenation of magmatic heat flux associated with Putauaki volcano superimposed on an area of multiple reactivated fault structures, sporadic magmatism and variable rates of subsidence. This study documents past patterns of fluid flow, temperatures and chemistry, and inferred permeability within the field. Using textural relationships in selected samples, the relative timing and patterns of hydrothermal alteration, and fluid flows can be established. These textural relationships are then calibrated against fluid inclusion palaeotemperature measurements and isotope data and related to temperatures and compositions of past fluids. Short–lived heat sources beneath the field resulted from local magma intrusions, and are responsible for the 0.36 Ma and 0.138 Ma rhyolites and Holocene eruptive activity of Putauaki andesite–dacite volcano. The Putauaki activity is inferred to be responsible for the thermal and alteration characteristics of the modern system.</p>

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