Introduction Brief Classification of Geothermal Resources
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Transcript Introduction Brief Classification of Geothermal Resources
EXPLORATION TECHNOLOGIES
WORKSHOP
Introduction & Brief
Classification of Geothermal
Resources
GRC Annual Meeting 2006
San Diego, California
Paul Brophy, EGS Inc.
Workshop Agenda
► Session
1
- Exploration Methods
► Session
2. - Exploration Case Histories
►Coso
►Roosevelt
►Karaha
► Session
Bodas (Indonesia)
3. - Panel Discussion
►What
Works- What doesn’t Work
Exploration Settings
Type A - Magma-heated, dry steam resources
(The Geysers)
Type B - Andesitic volcanic resources
(Philippines, Indonesia, Central &
South America)
Type C - Caldera resources
( Medicine Lake, Valles Caldera, Los
Humeros, Yellowstone)
Type D - Sedimentary–hosted, volcanic-related
resources (Imperial Valley)
Type E - Extensional tectonic, fault-controlled
resources (Great Basin)
Type F - Oceanic-ridge, basaltic resources
( Hawaii, Iceland, Azores)
Type A
Magma-related, Dry Steam Resources
(Example – The Geysers, CA)
Type A - Magma-related, Dry Steam
Resources
Topography:
Rugged? mountainous?
Climate:
Variable?
Depth to Resource:
meters)
Usually deep ( 2500 – 4000
Surface Manifestations:
Restricted
Permeability:
Low to moderate fracture
permeability
Environmental/Political: None
Type B Andesitic - Volcanic Resources
(Example – Systems of the Circum-Pacific)
Type B – Andesitic-Volcanic
Resources
Topography:
Usually mountainous
Climate:
precipitation
Variable – usually high
Depth to Resource:
Deep to moderate
Surface Manifestations:
Restricted – depending on depth
and shallow ground water
Permeability:
Low to moderate fracture
permeability – often highly
variable
Environmental/Political: Some countries with political
unrest
Type C - Caldera Resources
(Example – Medicine Lake, CA)
Type C – Caldera Resources
Topography:
caldera
Ring fractures often rugged,
floor gentle topgraphy
Climate:
Variable?
Depth to Resource:
meters)
Moderate to shallow (- 2500
Surface Manifestations:
Common
Permeability:
Low fracture permeability – often
with thick tuff units
Environmental/Political: Often very scenic –
environmentally
sensitive
Type D – Sedimentary-hosted,
Volcanic Resources
(Example – East Mesa, CA, Cerro Prieto, Mexico)
Type D – Sedimentary-hosted,
Volcanic Resources
Topography:
relief
Usually low topographic
Climate:
Arid, low precipitation
Depth to Resource:
Intermediate ( 2000 – 3500
meters)
Surface Manifestations:
Permeability:
Environmental/Political:
Very restricted
Variable?
Usually limited?
Type E – Extensional, Fault-controlled, Resources
(Examples – Dixie Valley, Desert Peak)
Type E – Extensional, Faultcontrolled
Resources
Topography:
Rugged on upthrow, low on valley
floor
Climate:
Usually dry with low precipitation
Depth to Resource:
meters)
Usually deep ( 2500 – 3500
Surface Manifestations:
Usually restricted to fault traces
Permeability:
Donimantly fault controlled
Environmental/Political: None
Type F - Oceanic, Basalt-hosted Resources
(Example – Puna, Hawaii)
Type F – Oceanic, Basalt-hosted
Resources
Topography:
Rugged to flat?
Climate:
Islands – high precipitation
Depth to Resource:
Shallow ( 1000 – 2000 meters)
Surface Manifestations:
Common
Permeability:
High horizontal permeability,
variable vertical permeability
Environmental/Political: Environmental sensitive