Investigations of deep resistivity structures at the Wairakei geothermal field

Bibby, H. M.; Risk, G. F.; Caldwell, T. G.; Heise, Wiebke

doi:10.1016/j.geothermics.2008.07.002

Cited by 23 publications

(8 citation statements)

References 24 publications

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“…Many references in the literature are concerned with the relationship between resistivity and rock temperature [7,28,30,32,33]. To map a temperature distribution based on MT and AMT results is problematic because too many factors can influence the electrical properties of rocks [30].…”

Section: The Geothermal Reservoirmentioning

confidence: 99%

Mapping the Geothermal System Using AMT and MT in the Mapamyum (QP) Field, Lake Manasarovar, Southwestern Tibet

Chen

Dorji

et al. 2016

Energies

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Southwestern Tibet plays a crucial role in the protection of the ecological environment and biodiversity of Southern Asia but lacks energy in terms of both power and fuel. The widely distributed geothermal resources in this region could be considered as potential alternative sources of power and heat. However, most of the known geothermal fields in Southwestern Tibet are poorly prospected and currently almost no geothermal energy is exploited. Here we present a case study mapping the Mapamyum (QP) geothermal field of Southwestern Tibet using audio magnetotellurics (AMT) and magnetotellurics (MT) methods. AMT in the frequency range 11.5-11,500 Hz was used to map the upper part of this geothermal reservoir to a depth of 1000 m, and MT in the frequency range 0.001-320 Hz was used to map the heat source, thermal fluid path, and lower part of the geothermal reservoir to a depth greater than 1000 m. Data from 1300 MT and 680 AMT stations were acquired around the geothermal field. Bostick conversion with electromagnetic array profiling (EMAP) filtering and nonlinear conjugate gradient inversion (NLCGI) was used for data inversion. The AMT and MT results presented here elucidate the geoelectric structure of the QP geothermal field, and provide a background for understanding the reservoir, the thermal fluid path, and the heat source of the geothermal system. We identified a low resistivity anomaly characterized by resistivity in the range of 1-8 Ω·m at a depth greater than 7 km. This feature was interpreted as a potential reflection of the partially melted magma in the upper crust, which might correlate to mantle upwelling along the Karakorum fault. It is likely that the magma is the heat source of the QP geothermal system, and potentially provides new geophysical evidence to understand the occurrence of the partially melted magmas in the upper crust in Southwestern Tibet.

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Section: The Geothermal Reservoirmentioning

confidence: 99%

Mapping the Geothermal System Using AMT and MT in the Mapamyum (QP) Field, Lake Manasarovar, Southwestern Tibet

Chen

Dorji

et al. 2016

Energies

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“…This funnel-shaped feature, which extends to the surface, is bounded on both sides by high resistivity structures; it coincides with the hot springs' locations, which exist between faults A and B ( Figure 5). The low resistivity is characteristic of a typical geothermal environment where saline hot fluid circulates within the reservoir and finds its way to the surface through a connecting path [37,38]. The geoelectric structure shows the subsurface faults which can be classified as normal fault with splays both to the west and to east.…”

Section: Profile Three (R3)mentioning

confidence: 99%

Integrated Remote Sensing and Geophysical Investigations of the Geodynamic Activities at Lake Magadi, Southern Kenyan Rift

Komolafe

Kuria

Woldai

et al. 2012

International Journal of Geophysics

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The tectonic lineaments and thermal structure of Lake Magadi, southern Kenyan rift system, were investigated using ASTER data and geophysical methods. Five N-S faults close to known hot springs were identified for geoelectric ground investigation. Aeromagnetic data were employed to further probe faults at greater depths and determine the Curie-point depth. Results indicate a funnel-shaped fluid-filled (mostly saline hydrothermal) zone with relatively low resistivity values of less than 1 Ω-m, separated by resistive structures to the west and east, to a depth of 75 m along the resistivity profiles. There was evidence of saline hydrothermal fluid flow toward the surface through the fault splays. The observed faults extend from the surface to a depth of 7.5 km and are probably the ones that bound the graben laterally. They serve as major conduits for the upward heat flux in the study area. The aeromagnetics spectral analysis also revealed heat source emplacement at a depth of about 12 km. The relative shallowness implies a high geothermal gradient evidenced in the surface manifestations of hot springs along the lake margins. Correlation of the heat source with the hypocenters showed that the seismogenetic zone exists directly above the magmatic intrusion, forming the commencement of geodynamic activities.

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“…Geothermal potential of the area was explored in detail with various scientific groups using diverse geophysical techniques (e.g.,Özürlan, Candansayar and Ş ahin 2006;Ç iftçti and Bozkurt 2010;Erdogan and Candansayar 2017). Among the geophysical techniques, resistivity surveys (i.e., Vertical electrical sounding (VES), electrical resistivity tomography, self-potential) are widely used and well suited to geothermal resource investigations since they are sensitive to variations in physical properties related to the hydrothermal processes (e.g., Ross, Green and Mackelprang 1996;Özürlan and Ş ahin 2004;Ozürlan et al 2006;Bibby et al 2009;Arango-Galvan et al 2011;Hermans et al 2014;Arango-Galvan, Prol-Ledesma and Torres-Vera 2015;Binley et al 2015;Kıyak et al 2015;Erdogan and Candansayar 2017). Presence of faults and fractures generate secondary porosity that may cause low resistivity signature (Robert et al 2011;Van Hoorde et al 2017).…”

Section: Introductionmentioning

confidence: 99%

Hydrogeophysical modelling of Hisarcik (Kütahya) geothermal field, western Turkey

Üner

Ağaçgözgü

Doǧan

2019

Geophysical Prospecting

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Western Anatolia hosts many low‐to‐moderate and high‐temperature geothermal sources in which active faults play a dominant role to control the recharge and the discharge of geothermal fluid. In this study, we used the two‐dimensional geoelectric structure of Kütahya Hisarcık geothermal field, and created a conceptual hydrogeophysical model that includes faults, real topographical variations and geological units. The temperature distribution and fluid flow pattern are also investigated. The depth extension of Hisarcık Fault, electrical basement and low resistivity anomalies related to the presence of geothermal fluid are determined by using resistivity studies in the area. Numerical simulations suggest that Hisarcık fault functioning as a fluid conduit primarily enables hot fluid to be transported from depth to the surface. It is shown that the locations of predicted outflow vents coincide with those of hot springs in the area.

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Investigations of deep resistivity structures at the Wairakei geothermal field

Cited by 23 publications

References 24 publications

Mapping the Geothermal System Using AMT and MT in the Mapamyum (QP) Field, Lake Manasarovar, Southwestern Tibet

Mapping the Geothermal System Using AMT and MT in the Mapamyum (QP) Field, Lake Manasarovar, Southwestern Tibet

Integrated Remote Sensing and Geophysical Investigations of the Geodynamic Activities at Lake Magadi, Southern Kenyan Rift

Hydrogeophysical modelling of Hisarcik (Kütahya) geothermal field, western Turkey

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