Analysis and interpretation of magnetotelluric data in characterization of geothermal resource in Eburru geothermal field, Kenya

Justus Maithya, Yasuhiro Fujimitsu

Research output: Contribution to journalArticle

Abstract

The magnetotelluric method (MT) is an essential geophysical method for the exploration of geothermal systems. In this study, the MT method was used to assess the extent of the geothermal resource in Eburru geothermal field, Kenya, with the aim of delineating the electrical conductivity structure of the area. Dimensionality analyses demonstrated that the MT data could be interpreted using two-dimensional approaches, but some localized 3-D effects were detected. A 2-D MT inversion was performed to generate resistivity models of Eburru geothermal field. Given its ability to recover complex resistivity models for the ground, three dimensional (3-D) MT inversion was also carried out, and a joint interpretation made from the 2-D and 3-D models. Both inversion approaches gave similar results and revealed a low resistivity layer (<10 Ωm) interpreted as clay cap, and an intermediate resistivity beneath interpreted as a geothermal reservoir immediately below the low resistivity. The sequence here infers the presence of geological structures controlling the geothermal system. The resistivity profiles analyzed revealed a structure of low resistivity (<10 Ωm) interpreted as the fluid pathway. This structure trend an S-N direction which is consistent with the faults orientation in the field and serves as a conducting channel for transporting heat from the heat source to the shallow region approximately 2 km above sea level.

Original languageEnglish
Pages (from-to)12-31
Number of pages20
JournalGeothermics
Volume81
DOIs
Publication statusPublished - Sep 1 2019

Fingerprint

Magnetotellurics
Geothermal fields
electrical resistivity
resource
Sea level
geothermal system
Clay
magnetotelluric method
Fluids
geophysical method
heat source
analysis
geological structure
electrical conductivity
method
sea level
Hot Temperature
clay
fluid

All Science Journal Classification (ASJC) codes

  • Renewable Energy, Sustainability and the Environment
  • Geotechnical Engineering and Engineering Geology
  • Geology

Cite this

Analysis and interpretation of magnetotelluric data in characterization of geothermal resource in Eburru geothermal field, Kenya. / Maithya, Justus; Fujimitsu, Yasuhiro.

In: Geothermics, Vol. 81, 01.09.2019, p. 12-31.

Research output: Contribution to journalArticle

@article{a1de24807c7047d4b34f22f1088de150,
title = "Analysis and interpretation of magnetotelluric data in characterization of geothermal resource in Eburru geothermal field, Kenya",
abstract = "The magnetotelluric method (MT) is an essential geophysical method for the exploration of geothermal systems. In this study, the MT method was used to assess the extent of the geothermal resource in Eburru geothermal field, Kenya, with the aim of delineating the electrical conductivity structure of the area. Dimensionality analyses demonstrated that the MT data could be interpreted using two-dimensional approaches, but some localized 3-D effects were detected. A 2-D MT inversion was performed to generate resistivity models of Eburru geothermal field. Given its ability to recover complex resistivity models for the ground, three dimensional (3-D) MT inversion was also carried out, and a joint interpretation made from the 2-D and 3-D models. Both inversion approaches gave similar results and revealed a low resistivity layer (<10 Ωm) interpreted as clay cap, and an intermediate resistivity beneath interpreted as a geothermal reservoir immediately below the low resistivity. The sequence here infers the presence of geological structures controlling the geothermal system. The resistivity profiles analyzed revealed a structure of low resistivity (<10 Ωm) interpreted as the fluid pathway. This structure trend an S-N direction which is consistent with the faults orientation in the field and serves as a conducting channel for transporting heat from the heat source to the shallow region approximately 2 km above sea level.",
author = "Justus Maithya and Yasuhiro Fujimitsu",
year = "2019",
month = "9",
day = "1",
doi = "10.1016/j.geothermics.2019.04.003",
language = "English",
volume = "81",
pages = "12--31",
journal = "Geothermics",
issn = "0375-6505",
publisher = "Elsevier Limited",

}

TY - JOUR

T1 - Analysis and interpretation of magnetotelluric data in characterization of geothermal resource in Eburru geothermal field, Kenya

AU - Maithya, Justus

AU - Fujimitsu, Yasuhiro

PY - 2019/9/1

Y1 - 2019/9/1

N2 - The magnetotelluric method (MT) is an essential geophysical method for the exploration of geothermal systems. In this study, the MT method was used to assess the extent of the geothermal resource in Eburru geothermal field, Kenya, with the aim of delineating the electrical conductivity structure of the area. Dimensionality analyses demonstrated that the MT data could be interpreted using two-dimensional approaches, but some localized 3-D effects were detected. A 2-D MT inversion was performed to generate resistivity models of Eburru geothermal field. Given its ability to recover complex resistivity models for the ground, three dimensional (3-D) MT inversion was also carried out, and a joint interpretation made from the 2-D and 3-D models. Both inversion approaches gave similar results and revealed a low resistivity layer (<10 Ωm) interpreted as clay cap, and an intermediate resistivity beneath interpreted as a geothermal reservoir immediately below the low resistivity. The sequence here infers the presence of geological structures controlling the geothermal system. The resistivity profiles analyzed revealed a structure of low resistivity (<10 Ωm) interpreted as the fluid pathway. This structure trend an S-N direction which is consistent with the faults orientation in the field and serves as a conducting channel for transporting heat from the heat source to the shallow region approximately 2 km above sea level.

AB - The magnetotelluric method (MT) is an essential geophysical method for the exploration of geothermal systems. In this study, the MT method was used to assess the extent of the geothermal resource in Eburru geothermal field, Kenya, with the aim of delineating the electrical conductivity structure of the area. Dimensionality analyses demonstrated that the MT data could be interpreted using two-dimensional approaches, but some localized 3-D effects were detected. A 2-D MT inversion was performed to generate resistivity models of Eburru geothermal field. Given its ability to recover complex resistivity models for the ground, three dimensional (3-D) MT inversion was also carried out, and a joint interpretation made from the 2-D and 3-D models. Both inversion approaches gave similar results and revealed a low resistivity layer (<10 Ωm) interpreted as clay cap, and an intermediate resistivity beneath interpreted as a geothermal reservoir immediately below the low resistivity. The sequence here infers the presence of geological structures controlling the geothermal system. The resistivity profiles analyzed revealed a structure of low resistivity (<10 Ωm) interpreted as the fluid pathway. This structure trend an S-N direction which is consistent with the faults orientation in the field and serves as a conducting channel for transporting heat from the heat source to the shallow region approximately 2 km above sea level.

UR - http://www.scopus.com/inward/record.url?scp=85064262363&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85064262363&partnerID=8YFLogxK

U2 - 10.1016/j.geothermics.2019.04.003

DO - 10.1016/j.geothermics.2019.04.003

M3 - Article

AN - SCOPUS:85064262363

VL - 81

SP - 12

EP - 31

JO - Geothermics

JF - Geothermics

SN - 0375-6505

ER -