Marine gravity & magnetic survey
Sevmorgeo State Company has up-to-date dedicated equipment and skilled personnel to carry out marine gravity and magnetometer surveys for oil and gas exploration, as well as for searching local magnetic anomalies – man-made objects (sunken vessels, pipelines, seabed cables and explosive items) on the sea floor.
Mobile gravimeter «Chekan-AM»
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«Chekan-AM»is designed for performing detailed marine gravimetrical observations, searching for oil-and-gas structures on the shelf and consists of gravity sensor and gyrostabilizer with in-built control system allowing to receive and record gravity data and navigation data from satellite receivers.
Data processing with accuracy evaluation and compilation of gravimetric charts is available.
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| Specification: «Chekan-AM» |
| Allowed absolute accuracy on fixed base |
+/- 0,2 mGal |
| Allowed absolute accuracy at sea |
+/- 0,5 mGal |
| Dynamic range |
Not less than 15 Gal |
| Required power |
No more than 700 W |
| Reading accuracy |
0.01 mGal |
| Measurement cycle |
1 s |
| Measurement range |
Not less than 10 Gal |
| Sensitivity (scale division) |
0.01 mGal |
| Response time |
35 to 100 s |
Uncertainty of evalutuion of zero creep
Prior estimation
Posterior estimation |
0,1 mGal/day
0,05 mGal/day |
| Uncertainty of gyroplatform
static
dynamic |
No more than 30"no more than 15" |
| Operating temperature |
(+)10-(+)30 С? |
| Interface |
RS- 232/RS-485 |
| Readiness time |
24 hours |
| Dimensions |
O430х638 mm |
| Weight |
72 kg |
Magnetic Gradiometry System from «Marine Magnetics»
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Scopes Marine Magnetometer Sea SPY:
Studying geological structures of a sea-bottom.
Magnetic Mapping when search for oil-and-gas potential fields on the shelf.
Search of ferromagnetic objects, High Res Magnetic Target Survey a horizontal differential mode (ships, an anchor, pipelines, cable lines, containers, explosive objects and other).
Geological mapping and construction maps of an anomaly magnetic field. |
| Technical characteristics «Sea SPY» |
| Offset between towfish |
50,100 м |
| Absolute accuracy |
0.2 nT |
| Sensor sensitivity |
0.01 nT |
| Counter sensitivity |
0.001 nT |
| Sampling Range |
4Hz - 0.1Hz |
| Operation Zones |
NONE |
| Course errors |
NONE |
| Range |
18,000nT -120,000nT |
| Gradient |
Over 10,000nT/m |
Integrated software and processing procedure
- Oasis Montaj – generation of geologic-geophysical maps and sections;
- Arc/Info, ER Mapper. – processing and mapping, data bases generation
- Tomography analysis –determination of anomaly geometry, magnetization and heterogeneity.
- Lineament analysis – lineament extraction, assessment of prevailing trends, permeability assessment.
Statistical analysis – identification and classification of anomalies, regression and topology analyses.
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Magnetic field map (Severo-Dolguinskaya prospective area)
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Local magnetic anomaly (dredge of 1 t in Ust’-Luga harbour)
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Local magnetic anomaly in the Barents Sea |
From 1997 to 2009 “Sevmorgeo” SC have been carrying out gravity & magnetic surveys in the Baltic, Barents, Kara, Bering, Chukcha and South-China Seas for various Russian and international projects.
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- 1997 – Participation in the International Environmental Project-97
- 1998 - Operations on the pipeline route in the Baltic sea)
- 1999 – Operations for fiber-optic communication link (the Baltic sea, Sea Systems)
- 1999 – Prospecting survey for Fe-Mn concretions (the Baltic sea, Petrotrans)
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- 2000 – Work out of recommended procedure of differential hydromagnetic surveys
- 2000 – Participation in engineering survey (12000 lin. km in the Bering and Choukcha Seas, Sea Systems)
- 2001 - Participation in engineering survey (The Barents Sea, AMIGE)
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- 2002 - Operations for fiber-optic communication link (the Baltic Sea, Hydroproject)
- 2002 – Participation in engineering survey (The Kara Sea, AMIGE)
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- 2005 – Reference geophysical line AP-4 (the Barents and Kara Seas, Sevmorgeo SC)
- 2006 –gravity & gradient magnetic survey (1900 lin. km, the South-China Sea, Sevmorneftegoefizika Trust)
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2007 – Gravity & Magnetic gradient survey (7000 lin. km, the South-China Sea, Sevmorneftegeofizika Trust) |
| 2008 – Gravity & Magnetic gradient survey (4500 lin. km, the Barents and Kara Seas, Sevmorneftegeofizika Trust) |
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- 2009 - Gravity & Magnetic gradient survey Reference geophysical line 1-OM (1500 lin. km, the Okhotsk Sea, ‘Sevmorgeo’ SC)
- 2009 – Gravity & Magnetic gradient survey (3500 lin. km, the Barents and Kara Seas, Sevmorneftegeofizika Trust)
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© 2010 «Sevmorgeo»
webmaster |
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36, Rosenstein Str., Saint-Petersburg, Russia, 198095
Phone:+7 812 252 67 67, Fax:+7 812 252 44 16
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