North-West Ltd. - EM surveying Provider

Regional studies

Regional-scale geophysical studies in Russia are used to be performed along separate profiles a few hundred to a few thousand kilometers long, verified by deep drilling.

Regional profile observations yield information on the deep structure of vast regions and allow solving some applied problems such as prognosis of oil and gas content in sedimentary basins, and delineating the zones perspective for solid mineral deposits. In active tectonic regions, data are obtained for studying the geodynamical conditions of the Earth's interior and forecasting the seismic activity.

Characteristic of regional studies is an integrated application of geophysical methods. This complex includes seismic, electromagnetic prospecting, gravity prospecting, magnetic prospecting and other methods including geochemical ones. The leading part in regional studies usually belongs to seismic: in most cases this method is capable of quite accurate location of geological boundaries. Other methods, first of all the electromagnetic prospecting, supplement these data with information about physical properties of rocks characterizing their lithology, fluid content, archeological conditions, etc.

Classification of the targets of regional deep geophysical studies:

reference profiles (length more than 500 km, measurements duration 2-5 years). Customer: Ministry of Natural Resources of the Russian Federation
regional profiles (length more than 100 km, measurements duration 1-2 years). Customer: Regional Subsoil Resources Management Agencies

Integrated geophysical studies:

seismic prospecting
electromagnetic prospecting
gravity prospecting
geochemical methods
airborne magnetic prospecting
other airborne techniques

Methods for electromagnetic studies along regional profiles:

MT: measurement sites spacing along the profile 3 km, f=0.0005÷200 Hz, record duration 12-16 hours, exploration depth 20-30 km

Long-period MT: measurement sites spacing along the profile 10-12 km, f=0.0001÷300 Hz, record duration 48 hours, exploration depth 40-60 km

AMT: measurement sites spacing along the profile 1 km, f=1÷100000 Hz (in case of MTU-5A), record duration 1 hour, exploration depth 0.5-1 km

	Moscow syneclise New information about the geoelectric structure of the Moscow syneclise, a vast tectonic structure within the craton, is obtained at Profile IV in the framework of the "Rifey" Programme.

	MT studies in Siberia Magnetotelluric technique has been utilized to image the deep structure of Siberian Craton. The detailed image of craton’s tectonic structures of various scale has been obtained as a result of MT data interpretation

	Regional 1-EV line In a framework of major regional-scale investigational project the studies of the Eastern European Craton’s deep geoelectrical structure have been carried out along the 1-EV profile more than 2000 km in length.

	MT studies in Volga region Large volume of geoelectrical data has been accumulated over the past years as a part of the studies of the Eastern European Craton sedimentary cover structure. The MT in Volga region has provided a valuable information on lithology and fluid regime of the sedimentary strata

Moscow syneclise

MT studies in Siberia

Regional 1-EV line

MT studies in Volga region