Geothermal Development in the Caribbean and EGS Perspectives
Geothermal Development in
the Volcanic Caribbean Islands
and EGS Perspectives
H. Traineau, B. Herbrich, E. Lasne, D. Tournaye
CFG Services, 3 av. Cl. Guillemin 45064-Orléans cedex 2 – France
A. Genter, B. Sanjuan
BRGM, 3 av. Cl. Guillemin, 45060-Orléans cedex 2 - France
ENGINE Launching Conference – Orléans, Feb. 12th to 15th, 2006
Geothermal Development in the Caribbean and EGS Perspectives
Map of the Caribbean volcanic
islands (red color) and their active
or recent volcanoes.
Subduction of the Atlantic Plate
below the Caribbean Plate
ENGINE Launching Conference – Orléans, Feb. 12th to 15th, 2006
Geothermal Development in the Caribbean and EGS Perspectives
Energy in the Caribbean
- More than 90% of electricity comes
from fossils fuels;
- Low contribution of Renewable energy
sources :
- Biomass
- Hydro
- Solar
- Wind
- Geothermal
- Electricity needs increase by 4-5%
every year.
ENGINE Launching Conference – Orléans, Feb. 12th to 15th, 2006
Geothermal Development in the Caribbean and EGS Perspectives
Volcanic
Islands
Survey
Prefeasibility
Deep
drillings
Saba
yes
St Eustatius
yes
St Kitts
yes
Nevis
yes
Montserrat
yes
yes
Guadeloupe
yes
yes
Dominica
yes
yes
Martinique
yes
yes
yes
Ste Lucia
yes
yes
yes
St Vincent
yes
yes
Grenada
yes
ENGINE Launching Conference – Orléans, Feb. 12th to 15th, 2006
Installed
capacity
(MWe)
Expected
Potential
(MWe)
10 - 50
yes
15
30 - 50
50 -100
10 - 50
Geothermal Development in the Caribbean and EGS Perspectives
Geothermal resources might contribute to
power generation in some islands instead
of fossil fuels
Bouillante, the case history
in Caribbean
Dominica, the most promising
geothermal potential
ENGINE Launching Conference – Orléans, Feb. 12th to 15th, 2006
Geothermal Development in the Caribbean and EGS Perspectives
The Bouillante geothermal field, Guadeloupe
Urban area
Steep topography area
Sea proximity
ENGINE Launching Conference – Orléans, Feb. 12th to 15th, 2006
Geothermal Development in the Caribbean and EGS Perspectives
The story of the Bouillante geothermal exploitation
1963
1969
1986
2001
2004
First survey
(BRGM)
First drillings
(EURAFREP)
First 4,5 MWe
power plant
(EDF)
Drilling 3 new wells
(GEOTHERMIE BOUILLANTE)
Second 11 MWe
power plant
(GEOTHERMIE BOUILLANTE)
ENGINE Launching Conference – Orléans, Feb. 12th to 15th, 2006
Geothermal Development in the Caribbean and EGS Perspectives
N
The Bouillante geothermal field
(O,84 My)
(O,6 My)
(1,12 My)
Pointe
à Lézard
Machette F.
(<O,6 My)
Bouillante
Bay
Marsolle F.
Bouillante
Bo-3
Caribbean
Sea
Bo-2
Cocagne F.
Bo-1
Bo-4
Bo-5
Bo-6
Bo-7
Main zone
of surface
manifestations
Hot spring
Muscade
(No date)
Main fault zones
(No date)
Inclined, deviated
production well
- Several main normal faults which
promote permeability and fluid
circulations at depth and represent
potential fractured reservoirs;
Descoudes F.
Recent volcanic
center (age M. y)
Exploratory well
- Several recent eruptive centers (<1
MA) around the Bouillante Bay, with
the possible occurrence of shallow
magmatic intrusion under cooling;
- Only a part of the reservoir is now
exploited through BO-4 vertical
production well, BO-5 and BO-6
deviated and inclined production wells
which intersect the Cocagne Fault.
Thomas
1 km
ENGINE Launching Conference – Orléans, Feb. 12th to 15th, 2006
Geothermal Development in the Caribbean and EGS Perspectives
Simplified model of fluid circulations in the Bouillante geothermal reservoir
Rainfall
Infiltration
Seawater
Infiltration
500 m
250°
1000 m
Fractured reservoir
Simplified cross-section along a West-East profile within the Bouillante
geothermal field showing the assumed model of fluid circulation with
seawater and rainfall recharge, mixing (60% seawater + 40% rainfall)
and heating to 250-270°C.
ENGINE Launching Conference – Orléans, Feb. 12th to 15th, 2006
Geothermal Development in the Caribbean and EGS Perspectives
ORKUSTOFNUN
COMPAGNIE FRANCAISE DE GEOTHERMIE
Bouillante Wells 2, 4, 5, 6 and 7
Temperature (°C)
60
80
100
120
140
160
Depth (m)
0
180
200
220
240
260
0
100
100
200
200
300
300
400
400
500
500
600
600
700
700
800
800
900
900
1000
1000
1100
1200
1300
BO-2, 16-03-2002 static
BO-4, 15-03-2002 static
BO-5, 13-03-2002 static
BO-6, 14-03-2002 static
BO-7, 13-03-2002 static
Selected temperature profiles in
the Bouillante wells.
240°C at shallow level (well BO-2)
Reservoir temperature
around 250°C
1100
1200
1300
ENGINE Launching Conference – Orléans, Feb. 12th to 15th, 2006
Geothermal Development in the Caribbean and EGS Perspectives
SE
NW
200
Descoudes
Fault
Plateau
Fault
Cocagne
Fault
200
0
Sea level
0
0
0
200
-200
-200
200
40
BO-2
-400
0
40
0
-400
60
60
0
0
600
-600
80
80
0
800
-800
1000
Location
of the main
feed zone
0
-600
Thick
calcite
vein
10
-800
00
100 0
120
1200
-1000
Cross-section along a NW-SE
profile showing well trajectories,
location and quality of permeable
zones in relation with faults
deduced from surface geology.
BO-6
0
-1000
140
120 0
- Plateau Fault shows low
permeability.
- Descoudes Fault has no permeability
possibly due to carbonates scaling
0
BO-7
-1200
- Only the Cocagne Fault appears to
be highly permeable.
-1200
140 0
-1400
-1400
BO-4
0
200
0
400
200 M
600
800
1000
1200
High permeable productive zone
Low permeable productive zone
ENGINE Launching Conference – Orléans, Feb. 12th to 15th, 2006
Geothermal Development in the Caribbean and EGS Perspectives
Main characteristics of the 7 deep wells drilled at Bouillante
Well
Year
Trajectory
Total length
(m)
Bottom hole
T (°C)
Result
No HP production
BO-1
1969
vertical
850
(225)
BO-2
1970
vertical
350
245-250
BO-3
1970
vertical
850
(245)
BO-4
1974-77
vertical
2 500
250
Low producer
(Stimulation needed)
BO-5
2001
deviated
1 197
250
Good producer
BO-6
2001
deviated
1 248
250
Good producer
BO-7
2001
deviated
1 400
240
No HP production
High temperature conditions at shallow depth
(< 1000 m deep) but strong anisotropy in
permeability related to fracture network and
possibly to scaling (carbonates, silica).
ENGINE Launching Conference – Orléans, Feb. 12th to 15th, 2006
Producer
No HP production
Geothermal Development in the Caribbean and EGS Perspectives
Main characteristic of the 7 deep wells drilled at Bouillante
Well
Year
Trajectory
Total length
(m)
Bottom hole
T (°C)
Result
No HP production
BO-1
1969
vertical
850
(225)
BO-2
1970
vertical
350
245-250
BO-3
1970
vertical
850
(245)
BO-4
1974-77
vertical
2 500
250
Low producer
(Stimulation needed)
BO-5
2001
deviated
1 197
250
Good producer
BO-6
2001
deviated
1 248
250
Good producer
BO-7
2001
deviated
1 400
240
No HP production
High temperature conditions at shallow depth
(< 1000 m deep) but strong anisotropy in
permeability related to fracture network and
possibly to scaling (carbonates, silica).
ENGINE Launching Conference – Orléans, Feb. 12th to 15th, 2006
Producer
No HP production
Extension of EGS methods
might be addressed first to
accurate location of faults
within the high temperature,
fracture-permeable reservoir.
Geothermal Development in the Caribbean and EGS Perspectives
Stimulation of the low productive well BO-4
COMPAGNIE FRANCAISE DE GEOTHERMIE
ORKUSTOFNUN
Calculated and Measured Production Characteristics of Well BO-4
160
A limited, low cost
experiment with cold
seawater injected into the
well BO-4 has been
conducted from August 10
- 27, 1998 to enhance the
secondary permeability
through thermal cracking.
140
Total Production Rate (t/h)
120
100
80
Conditions at first production test in 1998
Conditions at second production test in 1998
Measured point during second test in 1998
Measured points in July 1999
Measured points in May 2000
Approximate characteristic curve
60
40
Productivity increases by
50% and fluid discharge
is more stable.
20
0
0
2
4
6
8
10
12
14
16
18
20
22
Wellhead Pressure (bar-g)
ENGINE Launching Conference – Orléans, Feb. 12th to 15th, 2006
24
Geothermal Development in the Caribbean and EGS Perspectives
Stimulation of the low productive well BO-4
COMPAGNIE FRANCAISE DE GEOTHERMIE
ORKUSTOFNUN
Calculated and Measured Production Characteristics of Well BO-4
160
A limited, low cost
experiment with cold
seawater injected into the
well in steps has been
conducted from August 10
- 27, 1998 to enhance the
secondary permeability
through thermal cracking.
140
Total Production Rate (t/h)
120
100
80
Conditions at first production test in 1998
Conditions at second production test in 1998
Measured point during second test in 1998
Measured points in July 1999
Measured points in May 2000
Approximate characteristic curve
60
40
Productivity increases by
50% and fluid discharge
is more stable.
20
0
0
2
4
6
8
10
12
14
16
18
20
22
24
Wellhead Pressure (bar-g)
Extension of EGS methods could be
very useful to improve permeability of
low producers.
ENGINE Launching Conference – Orléans, Feb. 12th to 15th, 2006
Geothermal Development in the Caribbean and EGS Perspectives
Aerial view of the geothermal plant located within the city
Bouillante 1 Unit
(4,5 MWe)
Bouillante 2 Unit
(11 MWe)
The location of the plant within the city induced strong
environmental constraints (no noise, no steam plume, …).
ENGINE Launching Conference – Orléans, Feb. 12th to 15th, 2006
Geothermal Development in the Caribbean and EGS Perspectives
Aerial view of the well pad
and the pipe route.
Steep topography and urban
area reduce land availability
for well pads, pipe routes,
etc…, and consequently may
hinder best locations for
production and reinjection
zones.
ENGINE Launching Conference – Orléans, Feb. 12th to 15th, 2006
Geothermal Development in the Caribbean and EGS Perspectives
Bouillante
Sea proximity also reduces surface availability for well
siting and might require to reduce distances between
production and reinjection zones.
ENGINE Launching Conference – Orléans, Feb. 12th to 15th, 2006
Geothermal Development in the Caribbean and EGS Perspectives
Bouillante
Sea proximity also reduces surface availability for well
siting and might require to reduce distances between
production and reinjection zones.
Extension of EGS methods could be very
useful to improve and secure reservoir
monitoring and exploitation (tracer tests, …)
ENGINE Launching Conference – Orléans, Feb. 12th to 15th, 2006
Geothermal Development in the Caribbean and EGS Perspectives
Dominica Island
Valley of Desolation
Two promising high enthalpy geothermal
fields with abundant surface manifestations,
related to very recent volcanic activity.
Wotten Waven
Soufriere
ENGINE Launching Conference – Orléans, Feb. 12th to 15th, 2006
Geothermal Development in the Caribbean and EGS Perspectives
Dominica Island
Development of geothermal
resources in Dominica and reservoir
exploitation will face similar
problems as experienced in
Guadeloupe (remote location, steep
topography, national park, …)
Wotten Waven
Micotrin lava dome
ENGINE Launching Conference – Orléans, Feb. 12th to 15th, 2006
Valley of Desolation
Geothermal Development in the Caribbean and EGS Perspectives
Conceptual model of the Wotten Waven geothermal reservoir(s) with
inferred location of deep chloride reservoirs and fluid flow pattern.
ENGINE Launching Conference – Orléans, Feb. 12th to 15th, 2006
Geothermal Development in the Caribbean and EGS Perspectives
30
-5
0°
All structures (n=84 data)
N
N 00 -10
°
Rose diagram of fractures
recorded on the field
N80-100°
°
60
-1
40
N1
Strike
direction
Permeability within the basement is provided by fault
networks. Faults will be the main targets for well siting.
Equal area projection
lower hemispher
ENGINE Launching Conference – Orléans, Feb. 12th to 15th, 2006
Geothermal Development in the Caribbean and EGS Perspectives
CONCLUSIONS
Volcanic islands in the Caribbean have proved or expected high
enthalpy geothermal resources which could be used for electricity
production.
Due to their location, Bouillante and other fields (will) have to face
problems related to :
- Permeability anisotropy within the geothermal reservoir; wells have to
intersect main faults in order to be good producers;
- Steep topography and limited land availability for well pad, pipe routes,…;
- Environmental constraints due to urban areas or national park;
- Remote location (extra costs for survey, drilling, logging, stimulation and
work over operations, plant maintenance,…);
- Limited size of the exploitation and limited financial capacity of geothermal
operators;
ENGINE Launching Conference – Orléans, Feb. 12th to 15th, 2006
Geothermal Development in the Caribbean and EGS Perspectives
EGS PERSPECTIVES
Some problems could be addressed by EGS methods to
promote development of their geothermal resources :
- Accurate location of fault network;
- Permeability improvement through well stimulation;
- Reservoir monitoring (tracer tests, logging);
- Management of close production and reinjection zone;
- ….
ENGINE Launching Conference – Orléans, Feb. 12th to 15th, 2006