• 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