Geophysics

Marine Electromagnetic Prospecting

Abstract

The goal of study of the discipline is gaining knowledge about equipment and technologies of marine observations, marine electromagnetic data processing and interpretation, as well as about geoelectric structure of oceans and seas. On the basis of this knowledge it is possible to organize and supervise marine electromagnetic surveys, from data acquisition to interpretation.

Serction1. Technology of marine MT (magnetotelluric) soundings

• The influence of conductive water layer;
• Noise sources and methods for its depression;
• Equipment structure and observation technology;
• Methods for long-period variations registration.

Section 2. Interpretation of the oceanic MT anomalies

• MT field in horizontally inhomogeneous medium;
• Geoelectric inhomogeneity of a horst type;
• Coastal and island effects;
• MT data processing and interpretation graph.

Section 3. Results of MT soundings in the oceans

• First MT soundings in the Northern Pacific;
• Deep resistivity structure of the oceans;
• MT investigations if mid-ocean ridges;
• Marine MT exploration for oil and gas.

Section 4. Results of MT soundings in coastal zones

• MT soundings in the Far East of the USSR;
• MT soundings on the profile across the Sea of Japan;
• MT soundings in the Cascadia subduction zone;
• MT soundings on the west coast of Nicaragua.

Section 5. Theoretical basics and technology of FD CSEM (frequency-domain controlled-source electromagnetic) method

• Forward one-dimensional problem of FD CSEM method;
• Vertical and horizontal skin-effect;
• Apparent resistivity in in FD CSEM method;
• Equipment and observation technology.

Section 6. Case histories and results of FD CSEM

• Resistivity structure of the oceanic crust;
• Marine FD CSEM investigations of oceanic rift zones;
• Marine FD CSEM exploration for oil and gas;
• Near surface FD CSEM studies.

Section 7. Marine TD CSEM (time-domain controlled-source electromagnetic) investigations

• Equipment and observation technology;
• Calculation of transient sounding curves for polarizable medium;
• Method for the extraction of high-frequency signal component;
• Marine TD CSEM state of the art.

Duration ? 1 month.

Author: Associate Professor Pavel Pushkarev
Chair of Geophysics,
Faculty of Geology, MSU