INTERPRETATION OF GEOPHYSICAL DATA GRAVITY & MAGNETIC...
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Sustainable Development Goals Short Course IV on Exploration and Development of Geothermal Resources Anna Mwangi (PhD.), Senior Geophysicist, KenGen INTERPRETATION OF GEOPHYSICAL DATA GRAVITY & MAGNETIC METHODS 22/11/2019
Transcript of INTERPRETATION OF GEOPHYSICAL DATA GRAVITY & MAGNETIC...
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Sustainable Development Goals Short Course IV on Exploration and Development of Geothermal Resources
Anna Mwangi (PhD.), Senior Geophysicist, KenGen
INTERPRETATION OF GEOPHYSICAL DATAGRAVITY & MAGNETIC METHODS
22/11/2019
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SDG Short Course IV on Exploration and Development of Geothermal ResourcesOrganized by UNU-GTP and KenGen | Lake Bogoria and Lake Naivasha | Nov 14-4 Dec, 2019
GRAVITY METHOD
Distance (km)
Gra
vity
(m
Gal
s)
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SDG Short Course IV on Exploration and Development of Geothermal ResourcesOrganized by UNU-GTP and KenGen | Lake Bogoria and Lake Naivasha | Nov 14-4 Dec, 2019
GRAVITY METHODS
• Applicable to determine the density distribution in rock units
• Aim is to map density contrast within rocks
Method is cost effective and useful in:-
• Early stage exploration to locate anomalous magma bodies which are central in active geothermal systems
• Production stage in monitoring of geothermal reservoirs to ensure mitigation measure are used to maintain mass balance in the system.
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SDG Short Course IV on Exploration and Development of Geothermal ResourcesOrganized by UNU-GTP and KenGen | Lake Bogoria and Lake Naivasha | Nov 14-4 Dec, 2019
GRAVITY VALUES OLKARIA
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SDG Short Course IV on Exploration and Development of Geothermal ResourcesOrganized by UNU-GTP and KenGen | Lake Bogoria and Lake Naivasha | Nov 14-4 Dec, 2019
REGIONAL GRAVITY VALUES CENTRAL RIFT VOLCANOES
170000 190000 210000 230000 250000
Eastings(m)
9860000
9870000
9880000
9890000
9900000
9910000
9920000
9930000
No
rth
ing
s(m
)
-2200
-2120
-2040
-1960
-1880
-1800
-1720
-1640
-1560
-1480
SuswaCaldera
LongonotCaldera
Olkaria
g.u.
0.90S
1.20S
36.40
E36.20
E
0 10000 20000 (m)
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SDG Short Course IV on Exploration and Development of Geothermal ResourcesOrganized by UNU-GTP and KenGen | Lake Bogoria and Lake Naivasha | Nov 14-4 Dec, 2019
GRAVITY DATA REDUCTION
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SDG Short Course IV on Exploration and Development of Geothermal ResourcesOrganized by UNU-GTP and KenGen | Lake Bogoria and Lake Naivasha | Nov 14-4 Dec, 2019
GRAVITY BOUGUER ANOMALIES – OLKARIA DOMES
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SDG Short Course IV on Exploration and Development of Geothermal ResourcesOrganized by UNU-GTP and KenGen | Lake Bogoria and Lake Naivasha | Nov 14-4 Dec, 2019
ONGOING OLKARIA PRECISE MONITORING-GRAVITY
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SDG Short Course IV on Exploration and Development of Geothermal ResourcesOrganized by UNU-GTP and KenGen | Lake Bogoria and Lake Naivasha | Nov 14-4 Dec, 2019
MAGNETIC METHOD
• Investigate the magnetic property of rocks
• Geothermal environment are highly mineralized, mineral deposition along open structures hence magnetic minerals aggregate and hence there will be an increased magnetic field intensity.
• Useful in early stage exploration to locate geologic structures and
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SDG Short Course IV on Exploration and Development of Geothermal ResourcesOrganized by UNU-GTP and KenGen | Lake Bogoria and Lake Naivasha | Nov 14-4 Dec, 2019
MAGNETIC FIELD RESPONSE
Dyke intrusive magnetic body
Dep
th (m
)
Magn
etic field stren
gth
(m)
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SDG Short Course IV on Exploration and Development of Geothermal ResourcesOrganized by UNU-GTP and KenGen | Lake Bogoria and Lake Naivasha | Nov 14-4 Dec, 2019
TOTAL MAGNETIC INTENSITY - OLKARIA
(Mariita, 1995)
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SDG Short Course IV on Exploration and Development of Geothermal ResourcesOrganized by UNU-GTP and KenGen | Lake Bogoria and Lake Naivasha | Nov 14-4 Dec, 2019
EXAMPLE OF MAGNETIC ANOMALY MAP
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SDG Short Course IV on Exploration and Development of Geothermal ResourcesOrganized by UNU-GTP and KenGen | Lake Bogoria and Lake Naivasha | Nov 14-4 Dec, 2019
RESISTIVITY VS GRAVITY INTERPRETATION
4km depth resistivity slice
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SDG Short Course IV on Exploration and Development of Geothermal ResourcesOrganized by UNU-GTP and KenGen | Lake Bogoria and Lake Naivasha | Nov 14-4 Dec, 2019
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SDG Short Course IV on Exploration and Development of Geothermal ResourcesOrganized by UNU-GTP and KenGen | Lake Bogoria and Lake Naivasha | Nov 14-4 Dec, 2019
INFORMATION
Name of course: SDG Short Course IV on Exploration and Development of Geothermal Resources
Location: Lake Bogoria and Lake Naivasha, Kenya
Timing: November 14-December 4, 2019
Organized by: United Nations University Geothermal Training Programme (UNU-GTP) and Kenya Electricity Generating Company PLC (KenGen)
Financed by: UNU-GTP and KenGen
Presentation author(s): ([email protected])
Kenya Electricity Generating Company
P.O Box 20117, Naivasha, Kenya
www.kengen.co.ke
