NEW MEXICOGEOTHERMALResource Base, Exploration, and

Current Uses

GEOTHERMAL EXPLORATION, MCGREGOR RANGE, NEW MEXICO

Witcher

JAMES C WITCHERWITCHER AND ASSOCIATES

GEOTHERMAL – WHAT IS IT?• HEAT OF THE EARTH• RENEWABLE AND

SUSTAINABLE• ECONOMIC• EXTERNALITIES • LEASEABLE

MINERAL• WATER RESOURCE• SITE SPECIFIC

LAND VALUE HOMELAND

SECURITY

• DIRECT-USE OF HEAT ENERGY

• CONVERSION OF HEAT ENERGY ELECTRICITY

POWER

CHEMICAL FUELS REACTION

KINETICS OR SPEED

IMPORTANT PARAMETERS• Land

• Location and Infrastructure• Ownership• Institutional Setting

• Water• Sufficient for reservoir sustainability• Adequate for surface requirements

• Temperature

• EconomicsNPS, Saguaro National MonumentTucson, Arizona

GEOTHERMAL RESOURCE CLASSIFICATION

• HIGH TEMPERATURE RESOURCESGreater then 180 oC

• INTERMEDIATE TEMPERATURE RESOURCES

90 to 180 oC• LOW

TEMPERATURE RESOURCES

Less than 90 oC

Well testing AmeriCulture Well, Animas Valley, Lightning Dock KGRA , NM

Undiscovered Resources

McKELVEY DIAGRAM

Decreasing information about resource

Dec

reas

ing

qual

ity o

f res

ourc

eReserves

Undiscovered Resources

Sub-Economic Resources

• RESOURCEBASE

• RESERVES

Red Convective

Systems

Light BlueDeep Conductive

Systems in TertiaryBasins

Dark BlueDeep Conductive

Systems inPaleozoic and

Mesozoic Basins

GEOTHERMAL DOMAINS

TYPICAL CONVECTIVEGEOTHERMAL SYSTEM

CONTROLS• Heat Source• Structure

fracture permeability (reservoir permeability and storage) hydrogeologic windows (primary discharge site)

• Flow Dynamics Free convection (density driven flow) Forced convection (ground water head driven flow)

deep seated regional ground water flow systems thermal sweep of background regional heat flow

HEAT SOURCES• Favorable Shallow Magmatic

Large volume Pleistocene silicic volcanic center(Smith and Shaw, 1975 and 1979) Valles Caldera, Jemez Mountians, NM

Hulen and Nielson (1986)(Goff and Gardner, 1994 and 2004)

• High Regional Heat Flow Requires favorable Structure and

Hydrogeology May be enhanced by lower and

middle crust intrusions (basaltic)

STRUCTURAL SETTINGS• Laramide reverse faults and drape folds

Rincon Lightning Dock

• Pleistocene/Holocene rift normal faults Lightning Dock Rincon

• Ring fracture zones of Tertiary cauldrons Lightning Dock Socorro Peak

• Rift accommodation zones/normal fault transfer zones (ramps and relays)

Rincon Socorro Peak

HYDROGEOLOGYRift basin ground water flow constrictions (or outlets)

Hydrogeologic windows

OUTFLOW PLUME DYNAMICS• Mixing with near surface ground water.• Flow direction follows shallow hydraulic gradient.

• qz = k(dT/dz)– qz conductive heat

flow(mW/m2)– k thermal conductivity

(W/moK) – dT/dz temperature gradient

(oC/km)– k = 1.8 W/moK basin fill– k = 2.2 W/moK volcanics

• Q= qzdA - qbdA– Q total system heat loss– qb regional heat flow

(90 mW/m2)– dA area of integration

(km2)

TOTALCONDUCTIVEHEAT LOSS

Assumptions:• All heat is lost by conduction

over top of outflow plume.• Estimated thermal conductivity

does not introduce excessive error.• Borehole density is adequate to

characterize system.

EXAMPLE OF GEOTHERMAL SYSTEMSUBSURFACE THERMAL REGIME

• Annual temperaturewave near surface

• Conductive gradientabove water table orgeothermal system

• Temperature “rollover”in outflow plume

Red Convective

Systems

Light BlueDeep Conductive

Systems in TertiaryBasins

Dark BlueDeep Conductive

Systems inPaleozoic and

Mesozoic Basins

MCGREGOR

McGREGOR HEAT FLOW

•Maximum Heat Flow

454 mW/m2

• Area of Heat Flow

over 90 mW/m2

100 km2

• Reservoir Volume

>50 km3

• Heat Loss

>16 MWt

A GEOTHERMAL PROJECT• PERMITTING

• RESOURCE OWNERSHIP

• WATER RIGHTS

• ENGINEERING FEASIBILITY

• BUSINESS AND MARKETING PLAN

• FINANCING

• RESOURCE ASSESSMENT AND RESERVOIR CONFIRMATION

• PRODUCTION/INJECTION WELLS

• RESOURCE MANAGEMENT PLAN

• ENVIRONMENT AND PUBLIC RELATIONS

Alligator aquaculture, Mosca, Colorado

NREL

RESOURCE ASSESSMENT AND RESERVOIR CONFIRMATION

• SUFFICIENT HEAT

• PRODUCTIVE RESERVOIR

• SUSTAINABLE RESERVOIR

• SHALLOW IS BEST

Core, Rincon 1, Rincon, New Mexico

Witcher

250 ft832 ft

Witcher

WHAT IS THEEXPLORATION TARGET?

Structure controls

Aquifers(reservoirs)Properties

Aquitards (caps)

HydrogeologyFlowpath

Heat SourcesThermal Sweep?

Example Resource and Exploration Model

Witcher

CONVERT EXPLORATION BUDGET INTO USEABLE HEAT

• Reservoir GeologyStructureStratigraphy

• GeophysicsDirect Method (heat

flow)Proxy Methods

(resistivity)Structural Methods

(gravity, seismic)• GeochemistryGeothermometrySoil gas

Rincon 1, Rincon, New Mexico

Witcher

TEMPERATURE GRADIENT ANDHEAT FLOW HOLES

• Shallow (100 TO 300 ft)

• Small drill rig

• Complete with 1-2 inch PVC or iron pipe filled with water and annulus backfielded with cement or cuttings

• Two of three wells per day

• Costs ($15 TO $35/ft)

Temperature Gradient/Heat Flow Drillingnear Safford, Arizona

Witcher

SLIM-HOLE EXPLORATION HOLES

• SMALLER DIAMETER ROTARY HOLES

• 500 TO 5,000 ft DEPTH

• CONTINUOUS WIRE-LINE ROTARY CORE DRILLING

• COSTS ($75 TO $150/ft)

Alpine Geothermal Test Hole, Alpine, Arizona

Witcher

• Determine reservoirhydraulic properties

• Obtain water chemistryand isotopic data

• Estimate long-termdrawdown (sustainability)

• Manage reservoirMonitor chemistryMonitor water levelsMonitor temperatureRecord production

Pump Test, AmeriCulture 1, Lightning Dock, Animas, New Mexico

Witcher

RESERVOIR TESTING AND MONITORING

Red Convective

Systems

Light BlueDeep Conductive

Systems in TertiaryBasins

Dark BlueDeep Conductive

Systems inPaleozoic and

Mesozoic Basins

MONTEZUMA HOT SPRINGS

MONTEZUMA HOT SPRINGS

• TDS – 864 mg/L• 55o C surface discharge• Sodium chloride water• 171 gpm maximum total flow

into the Gallinas River

• Qtz – 119o C• Chalcedony – 89o C• Regional heat flow

60 to 80 mW/m2

From Baltz (1972)

NOMENCLATURE AND FRACTURE PERMEABILITY MODEL

• ForelimbDomain

• Nature ofBasement Fabric

• ReservoirHost?

• Barrier toLateral Flow?

MODEL APPLICATION TOMONTEZUMA HOT SPRINGS

• Section A-B planar view

• Section C-D perpendicular view Note:Importance of crushed rock zonesat Montezuma HS recognized by Bejnar and Bejnar (1979)

HIGHLY GENERALIZED TERTIARY SUBCROP MAP

• Precambrian andPaleozoic subcrop(brown)

• Convective geothermal systems(black squares)

• Associated with Laramide and Late Paleozoic Basement Uplifts

GEOTHERMAL SYSTEMSAROUND THE LARAMIDERIO GRANDE UPLIFT

System located on or adjacent to fold-faultstructures:

• San Diego Mtn• Hot Springs• Rincon• Lake Valley• Animas• Salado• Radium Springs• Derry• East Portrillo

Modified from Seager and Mack (2003)

Red Convective

Systems

Light BlueDeep Conductive

Systems in TertiaryBasins

Dark BlueDeep Conductive

Systems inPaleozoic and

Mesozoic Basins

RINCON

RINCON GEOTHERMAL SYSTEM

• Extensive opal and siliceous sinter deposits

• Total heat loss >10 MWt

• > 150o C geothermometer temperatures

RINCON CROSS SECTION

• Laramide subsurface structure inferred from overturned limestone outcrop 4 miles to north

• Hydrogeologic windows between Paleozoic carbonates and Tertiary Thurman Formation

• Tertiary Palm Park Formation forms confining cap rock

Cross section in Tertiary rocks based uponSeager and Hawley (1973)

Red Convective

Systems

Light BlueDeep Conductive

Systems in TertiaryBasins

Dark BlueDeep Conductive

Systems inPaleozoic and

Mesozoic Basins

LIGHTNING DOCK

LIGHTNING DOCK

REGION

• Potential for deep seated fracture permeability

• Structures have long and repeated deformation history

From Kucks and others (2001)

From various sources (Titley (1976), Swan (1976), Seager (2004), Lawton (2000) and others

SUMMARY GEOLOGIC LOG OF THEAMERICULTURE 2 WELL

COMPLETE BOUGUER GRAVITY MAP OF LIGHTNING DOCK REGION

Geothermal system iscontained within a buried intrabasin horstBlock.

LOCATION MAP OF WELLS, FAULTS,AND CROSS SECTION LINES

GEOLOGIC CROSS SECTION 2

QTgc – basin fill/Gila Conglomerate

Tv – Tertiary volcanics

JKbg – Mesozoic Bisbee Group

PPh – Paleozoic limestone

QTgc – basin fill/Gila Conglomerate

Trf – ring fracture zone rhyolite

Tv – Tertiary volcanics

JKbg – Mesozoic Bisbee Group

PPh – Paleozoic limestone

GEOLOGIC CROSS SECTION 1

SUMMARY OFLIGHTNING DOCKSTRUCTURAL ELEMENTS

1) Cockrell 1 Pyramid2) AmeriCulture 23) Steam Reserve 55-7

COMMON COMPONENTS OF UTILIZATION

• WELLS

• HEAT EXCHANGERS

• PIPELINES

Drilling AmeriCulture State 2, Lightning Dock, Animas, New Mexico, AmeriCulture Geothermal Tilapia Farm

Witcher

HEAT EXCHANGERS

Haslego and Polley (2002)

• Prevent scaling and corrosion

• Isolate geothermal fluids from heating equipment andenvironment

• Plate and frame heat exchangersare very efficient

NMSU

APPLICATION CATEGORIES

• ELECTRICAL POWER

• DIRECT-USE

• GROUND-COUPLED HEAT PUMP

USDOE USDOE

BINARY-CYCLE POWER

USDOE

WitcherSoda Lake, Nevada, 26.1 MWe Binary Power Plant

Witcher

TEMPERATURE AND PRODUCTION RATE

REQUIREMENTS

BarberNichols

0

20

40

60

80

100

Wind Solar Hydro Average Biomass Fossil Geothermal

Nuclear

CAPACITY FACTORS

Roger Hill, SNL

COST OF BINARY POWER

• 210 to 260 oF• 1 to 5 MWe• Hydrothermal Resource

ConvectiveDeep Conductive

• Water Cooled Condenser (water rights)

• Inefficiency in New Mexico Summer

• Levelized Cost (30-yr)Includes Capital and O&M$0.055 to $0.085 per kWh

• Capital Cost$3,500 to $4,500 per kW

• O&M$0.02 to $0.03 per kWh

DIRECT-USEANY PROCESS THAT REQUIRES LARGE AMOUNTS OF LOW-GRADE HEAT

• DISTRICT HEATING• AGRICULTURE APPLICATIONS• INDUSTRIAL APPLICATIONS

USDOEMasson Geothermal Greenhouse, Radium Springs, New Mexico

Williamson, NREL

LINDAL DIAGRAM

NMBGMR, Earth Matters, Summer, 2006, modified from Geothermal Education Office

OTHER USES ?

Desalination

Copper/Gold

Biofuels (algae)

Burgett Geothermal Greenhouse

AmeriCulture Geothermal Tilapia Farm

Burgett Geothermal Power Plant (Binary)

BURGETT GREENHOUSE, LIGHTNING DOCK, 30 acres

USGS

AMERICULTURE TILAPIA FARM, LIGHTNING DOCK

• CONTROL CONSTANT TEMPERATURE FOR OPTIMAL GROWTH

• SUPPLIER OF TILAPIA FRYACROSS US

• FULL SIZE GROWOUT OF TILAPIA AND LIVE TILAPIA SUPPLIER FOR RESTAURANTS IN PHOENIX AND TUCSON

Tilapia

AmeriCultureAmeriCulture

MASSON GEOTHERMAL GREENHOUSE, RADIUM SPRINGS

18 acre

Williamson, NREL

CONCLUSIONS

Heat Flow units mW/m2

(milliwatts per square meter)

Blackwell, SMU

• Access to transmission • Access to land and mineral rights• Risk not well understood by developers and investors• Public and regulators not aware or educated on geothermal • Has smallest environmental footprint most all energy resources• Competes economically with fossil fuels• High initial capital costs• Resource poorly known

• Direct-use geothermalis an important vehicle forrural economic development.

• An acre of geothermal greenhouse has severaltimes greater cash flow than production of 1 MWe of electrical power fromgeothermal.