Upload
others
View
9
Download
0
Embed Size (px)
Citation preview
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
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)
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.
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
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)
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
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
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
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
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)
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)
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
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
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
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