Time Domain Electromagnetic Surveys
Knowledge in the Field
Time domain electromagnetic (TDEM) surveys are useful in rapidly mapping 2D electrical conductivity / resistivity using vertical EM soundings. These are assembled to create a 2D conductivity profile as a complement to a seismic section. Electrical resistivity sections can be very useful in constraining subsalt geometry and in locating large scale basement structures. The technique has been applied in the Coleville Hills area of the NWT and in northern Saskatchewan to successfully assist oil & gas exploration projects.
AGL offers TDEM surveys using the Geonics Protem EM-67 system. Using variable loop geometries, these surveys can be adjusted to deliver depths of investigation in excess of 3000 m in moderately conductive environments. Results are interpreted using the Geopak REVS, TEMIX to yield vertical 2D depth sections.