fundamentals of operational display – ½ day magnetic principles – ½ day operational display...
TRANSCRIPT
• Fundamentals of Operational Display – ½ day• Magnetic Principles – ½ day• Operational display and Search Patten Planning – ½ day• Search Pattern Planning – ½ day• Post Processing – ½ day
OutlineG-882 Cesium Marine Magnetometer Training Course
IntroductionGeometrics, Inc.Premier Manufacturer of Marine Magnetometers
Slide 2
Single sensor
Magnetic surveying is used to provide basic geologic information for oil/gas exploration and marine mining projects. It is used to do basic research into rock types and geothermal activity including the location of kimberlite diamond pipes. It is used to locate dumping grounds of toxic materials, ancient and valuable shipwrecks of archeological significance. Magnetometry is used as a security tool to ensure that harbors and near coastal zones are clear of submarines and other military material such as mines.
Marine Magnetometer – G-882
Slide 3
Marine magnetometers are deployed in coastal zones the world over for geological, military, environmental, archeological and marine engineering purposes.
Provides the maximum detection capability for
* sunken vessels
* pipelines
* sewage outfalls
* fiberoptic telecommunication cables
* power cables
* various other infrastructure components
G-880 with Flotation Device
Slide 4
Earth’s Magnetic FieldEarth’s Magnetic Field: detection of magnetic anomalies
• Earth’s dipole magnetic field is perturbed by relatively localized contrasts in magnetization.
• Magnetization contrasts are caused by ferrous debris, vessels, pipelines, communication cables, magnetic minerals (predominantly magnetite).
• With magnetometers, one can measure the total field to detect the magnetic anomalies associated with contrasts.
• Earth’s dipole (N-S) magnetic field is produced by internal iron core dynamo effect. Charged particles from the sun cause a bow shock wave in the magnetosphere which leads to Diurnal Variations
Slide 5
Typical marine magnetometer system set-up for single sensor survey
SENSOR
SHIP
ON-BOARD DATA LOGGER AND PROCESSOR
Not to scale
GPS
MAGNETICBODY
North
Data Acquisition: Single Sensor without Telemetry
Slide 6
Typical marine magnetometer system set-up for dual sensor (gradiometer) arrays
SLAVE SENSOR
MASTER SENSOR
SHIP
ON-BOARD DATA LOGGER AND PROCESSOR
Not to scale
GPS
MAGNETICBODY
North
Data Acquisition: Gradiometer without Telemetry
Slide 7
Typical marine magnetometer system set-up for single sensor survey
TELEMETRY SENSOR
SHIP
ON-BOARD DATA LOGGER AND PROCESSOR
Not to scale
GPS
MAGNETICBODY
North
Data Acquisition: Single Sensor with Telemetry
Slide 8
Typical marine magnetometer system set-up for dual sensor (gradiometer) arrays
TELEMETRY
SLAVE SENSOR
MASTER SENSOR
SHIP
ON-BOARD DATA LOGGER AND PROCESSOR
Not to scale
GPS
MAGNETICBODY
North
Data Acquisition: Gradiometer with Telemetry
Slide 9
Slide 10
Cable Profile
DC Power Supply 28-35VDC
MagLogData
Logger
60-450m
Short Cable Cesium Magnetometer Diagram
RS232
Junction Box
On-Board Cable
RS-232 &PowerWinch
Sensor
Electronics DriverAnd CM222 Counter
G-882 SystemBlock Diagram
COMPUTER
Slide 11
Remote Sensing DC Power Supply 28-60VDC
MagLogData
Logger
60-600m
RS232
Junction Box
On-Board Cable
RS-232 &Power
Winch
Slave Sensor
G-882 SystemBlock Diagram
COMPUTER
Master Sensor
Electronics DriverAnd CM222 Counter
Medium Cable Cesium Magnetometer Diagram
Slide 12
Constant Current DC Power Supply 13-160VDC
MagLogData
Logger
60-6000m
RS232
Junction Box
On-Board Cable
RS-232 &Power
Winch
Slave Sensor
G-882 SystemBlock Diagram
COMPUTER
Master Sensor
Electronics DriverAnd CM222 Counter
Telemetry
Deep Tow Cesium Magnetometer Diagram
Slide 13
G-880 Magnetometer Sensor Pressure Vessels
Slide 14
MagLogNT Digital Data Acquisition System with position interpolation
Slide 15
MagLogNT
And
MagLogLite
Data Acquisition Software
Slide 16
MagMap2000
Data Processing Software
Slide 17
Using 34 meter GPS Offset Correction No GPS offset Correction
GPS Offset Correction Contour Maps
Slide 18
Using 34 meter GPS Offset Correction No GPS offset Correction
GPS Offset Correction Profiles
Slide 19
Distance in meters54950 55000 55050 54950 55000 55050
Mag
neti
cs in
nT
49000
49750
50250
Magnetic Model of 20 Meter Sunken Ship at 300 Meters Depth
Slide 20
Data Courtesyof Ark Geophysics
Seabed Cable Anomaly Detail - 3 km filter (note scale of anomalyis high-resolution at 0.22 nT).
Data Processing – Pipeline Contour Map
Slide 21