Geothermal Studies at New Mexico Tech

New Mexico Geothermal Energy Working Group Meeting

May 13, 2008

Jungho Park

New Mexico Geothermal ProgramSystems Studied:Coso, CASalton Sea, CAThe Geysers, CASteamboat Springs, NVDixie Valley, NVDarajat, and Karaha Telaga Bodas, IndonesiaTiwi, PhillipinesLightningdock,NMValles, NM

Some projects we are working on:

• Fluid Inclusion Stratigraphy

• Icelandic Deep Drilling Project

• Scale mitigation of injection wells

• New Mexico Tech geothermal exploration well

Development of FIS for Geothermal

Exploration

• FIS “fluid inclusion stratigraphy”

• Invented to find hydrocarbon “pay zones”

• Measures fluid inclusion volatiles in well cuttings which we apply to Geothermal wells

FIS Analysis of Geothermal Well Cuttings Compared to Temperature Log

Well 67-17

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Temperature (F)

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In general what we see from bottom to system top in the

Coso Geothermal System.

Plume waters and mixed plume fluids,production zone

Seal or cap

Meteoric waters heated by steam of conduction,

Discontinuous background or dead zone where no fluids circulate

FIS Fence Diagram of

Part of Coso

LEGEND

SE NW

Icelandic Deep Drilling Project

• Krafla, Iceland

• Attempt to drill over 5km deep and capture geothermal fluids in the supercritical phase (>374C) for increased electrical production

• Characterize fluid compositions and interaction with volcanic source using inclusion gas analyses of core and cuttings

KraflaKrafla

Socorro PeakExploration Drilling

•Initiative: New Mexico Tech Campus direct-use heating system

•Need >60°C geothermal fluid produced at a moderate flow rate @ 300 gallons per minute

•2004 (at time of grant) – offset $600K in natural gas costs

•2007 prices – offset risen to ~$1.2M

•Resource: The Socorro Peak, a region of elevated heatflow with values upwards of 470 mW/m2 within quartzite mountain block

•Warm springs (30°C) to the south

Multiple MethodsMultiple Methods

•Magnetotellurics•Resistivity•Gravity•Remote Sensing•Geochemical Mapping•CO2 Soil Surveys

Socorro Peak Thermal Gradient (Barroll and Reiter, 1990)

SocorroSocorro

500m

•Executed along front range

•Imaged a low resistivity body (blue) within Basin possibly representing saturated geothermal reservoir

•More resistive (red) unit representing uplifted fault block

Resistivity

Magnetotellurics SurveyMagnetotellurics Survey

N

1000 m

121086420

Relative Temp Elevation (C)

Remote Sensing•Satellite-based infrared imagery (ASTER data)

•Max >12ºC above ambient near Woods Tunnel

Town of

Socorro

Socorro Peak

Woods Tunnel = 490 mW/m2

Geochemical Mapping•Soil sampled along E-W transects crossing range-bounding faults

•Selective extraction of soils to isolate loosely-adsorbed volatiles

•Trace elements composition of substrate measured with ICP-MS

•Elemental maps reveal anomalous high intensities along range front coinciding with structural features and highest measured heat flow

NN

Drilling Results• DOSECC began

drilling Nov-Dec 2006

• Bedrock encountered @ 165ft, heavily fractured and mineralized

• Watertable @ ~200ft depth

• Bottom hole temp of 33.5C was measured at a depth (240ft)

Entrance to Woods Tunnel

217’

216’

y = 16.036x - 299.81

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Temp (ºC)D

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65

742’

•Shallow thermal gradient projected to 742ft depth gives necessary 65C for district heat-loop

•Quartz (Fournier) geothermometer from well fluids = 100C reservoir

•K-Mg-Na (Giggenbach) geothermometer = >150C

Well 67-17

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Temperature (F)

Gas species: inorganic, organic,sulfur (orange), aromatics

Gas ratios for interpretingfluid source

Well 51B-16

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Temperature (F)

Generally Easy to See Fluid Stratigraphy