Marine Magnetotellurics for Geothermal Exploration under the Salton Sea

1
Marine Magnetotellurics for Geothermal
Exploration under the Salton Sea

Edward Nichols, Jiuping Chen, (Schlumberger -
EMI) Tiziano Labruzzo (AGO) Dennis Kaspereit,
Brian Berard (CalEnergy) Pablo Gutiérrez (CEC)
EMI Technology Center, Schlumberger Sept, 2006
2
Salton Sea Survey Plan Target Identify high
conductivity zones related to hot brines in the
reservoir. 4 Profiles (72 km) 93 sites
proposed 30 land owners
(3-D map by Dave Miller http//www.stanford.edu/d
miller/dem1.html )
3
Objective Evaluate offshore extension of
geothermal field with marine MT Tasks Modify
Deep Marine MT for operations in Salton Sea (lt15
m depth) Collect 50 marine and 30 land MT
stations along profiles Perform interpretation
using 2-d models on profiles
4
Geothermal Exploration under the Salton Sea using
Marine Magnetotellurics

• Stage 1 - Planning
• Design Initial Survey Layout
• Preliminary deployment
• Develop survey plan
• Stage 2 - Conduct Full Survey
• 80 MT stationsarranged in 4 profiles
• Deployment (marine stations)
• Deployment (land stations)
• Stage 3 - Reduce and Interpret data
• Reduce data
• Preliminary Interpretation
• 2D Computer inversion on profiles
• Construct geological/reservoir model

5
MMT24
Stray Line Flotation Ball
Flotation package
BFM Marine Sensors
Anchor Release Mechanism
ANCHOR
Electrode Arms
Electrode
EMI MMT24 System Jamestec 2001 Deployment -
Water Depth 5.6 km - Sea of Japan
6
MMT24 Shallow Water MT System
Test Survey Site 6 Water Depth 6
7
The MT Method
8
Challenges of Marine Magnetotellurics in the
Salton Sea

• Data quality - EM Noise from very large power
  generation facilities and transmission
  lines
• Shallow sea small boats, difficult access, wave
  noise, river currents, caution for
  interference to boaters
• High salinity corrosion of equipment,
  electrical contacts

9
Hx
Ex1
Good signal
Ex2
Ey1
Hy
10
Survey - December 2003 RS3 5 channel MT.
12 miles away RS4 4 channel MT. 22 miles
away Survey - March 2004 RR6 4 channel MT.
43 miles away RR8 4 channel MT. 57
miles away
REMOTE REFERENCE LAYOUT
11
L2-08S EMI, Mar. 2004
L2-12S EMI, Mar. 2004
Comparison With Existing MT Data
WC-5 Woodward-Clyde, May. 1979
12
Marine Operations
Marine Sites SSX17 and 45
13
Line 2 Inverted 2D resistivity profile
With fix zone
14
The data fitting for the old, inverted model
15
Line2 -- 2D MT inversions
16
Salton Sea
17
(No Transcript)
18
(No Transcript)
19
Conclusions

• Shallow water marine MT is possible
• Data matches old surveys
• Correlation with well log
• Patience to work with weather conditions
• Interpretation needs geologic integration and
  fill in data
• Energy climate is ready for more marine MT
  exploration
• Other shallow marine target areas may be
• Clear Lake, Surprise Valley
• International Gulf of California, Indonesia,
  Iceland, Japan

20
Geothermal Exploration under the Salton Sea using
Marine Magnetotellurics

• Acknowledgements
• CalEnergy
• Geological Information - Dennis Kaspereit, Fred
  Pulka
• Land Owners - Vince Signoritti
• Sonny Bono Wildlife Refuge
• Sylvia Pelizza - Land and special use advice
• Daniel Gomez - CDFG
• Wister Game Reserve
• Jack Crayon - Game Warden - air boat logistics
• Rob Schrag - air boat operator
• Contractors
• John Greenman
• Rays Fishing Guide Service
• GeoInvest
• Schlumberger
• Nestor Cuevas
• Kevin Eyl
• Rebecca Harvey

21

• EMI Survey equipment, s/w
• Cal Energy Reservoir information
• CEC Funding, Project review