NORD
Multifunctional electromagnetic receiving system for magnetotelluric (MT) and controlled-source electromagnetic (CSEM) methods
NORD system
designed for registration of electromagnetic field components in geophysical exploration
FIELD OF USE
FIELD OF USE
- Mineral exploration, including solid minerals, hydrocarbon, geothermal sources and underground water deposits;
- Regional geological study;
- Research of the deep Earth structure.
METHODS
METHODS
- The magnetolluric (MT, AMT) method, based on observation of the natural electromagnetic field variations.
- Controlled-source electromagnetics (CSEM, CSAMT), which employs the artificial electromagnetic field to infer the deep structure of Earth.
KEY ELEMENTS OF THE SYSTEM:
NORD receiver
NORD is a modern digital receiving unit, specially designed to register the amplitude and time variations of the EM field components. The receiver has 2 electric and 3 magnetic channels, each one equipped with a separate 32-bit ADC with a sampling rate of 2400 Hz and 24-bit ADC with a sampling rate of 312.5 or 78.125 kHz for audiomagnetotellurics (AMT).
METHODS
Magnetotelluric (MT) method — observation of natural EM field of the Earth. Including the Audio MT (AMT) and Broadband MT (AMT + MT).
Controlled-source electromagnetics (CSEM, CSMT) — working with controlled (man-made) sources of EM field.
Controlled-source electromagnetics (CSEM, CSMT) — working with controlled (man-made) sources of EM field.
PROCESSING
Field processing of NORD data can be carried out in real time using the Android software without interrupting the recording.
The final processing of the data received by the NORD is carried out after the end of the recording on any computer running Windows. EPI-KIT software is used for the final processing. It is included in the delivery set.
The final processing of the data received by the NORD is carried out after the end of the recording on any computer running Windows. EPI-KIT software is used for the final processing. It is included in the delivery set.
Operation
Handling NORD receiver, adjusting its settings, monitoring and downloading the acquired data could be made with a smartphone or any other gadget with a Wi-Fi module and a web browser. Starting a new record without changing the actual NORD settings is also possible with the built-in Start/Stop button.
The control program for Android has great functionality and provides the ability to carry out operational processing of NORD data in real time without interrupting the recording. To use the program, you need a smartphone or tablet running Android 7.0 or higher.
The control program for Android has great functionality and provides the ability to carry out operational processing of NORD data in real time without interrupting the recording. To use the program, you need a smartphone or tablet running Android 7.0 or higher.
Technical specifications
of NORD receivers
| Parameter | Value |
|---|---|
| Number of channels | 5 (2 electric, 3 magnetic) |
| Measured field components | Ex, Ey, Hx, Hy, Hz |
| Operation frequency range: 32-bit ADC 24-bit ADC | DC - 1000 Hz 5 - 100 000 Hz |
| ADC, on each channel: | 32 bit+ 24 bit |
| Sampling frequencies: 32-bit ADC 24-bit ADC | 2400, 150 and 15 Hz 312.5 and 78.125 kHz |
| Input resistance | 10 MΩ |
| Input capacitance | < 0.5 nF |
| Max. measured voltage | E channels: +/- 600 mV Н channels: +/- 10000 mV |
| Сommon-mode noise rejection in operating band | > 120 dB |
| Self-noise level | ~3.5 nV/√Hz |
| Data transfer interface | Wi-Fi 802.11n |
| Positioning accuracy with GPS, BeiDou and/or GLONASS systems | +/- 1 m, when synchronized with 12+ satellites |
| Time synchronization accuracy | +/- 30 ns (standard deviation) |
| Integral solid-state drive | 32 GB Industrial Grade (optionally - up to 256 GB) |
| Weight | 1.8 kg |
| Dimensions | 20x10x13 cm |
| Power supply voltage | 12 V |
| Ingress protection code | IP-65 |
| Power consumption: | 6 - 8.5 W |
| Operating temperature range | -40 … +85 °C |
- REAL-time processing, VISUALIZTION OF TIME SERIES, SPECTRA AND SIGNAL COHERENCIES DURING THE MEASUREMENT.
- Built-in sensors: power supply voltage and current load, ADC and processor temperature, air pressure and humidity inside the casing.
- built-in power supply overvoltage, short-cut and inverse polarity protection system.
- built-in static discharge and lightning protection system.
- built-in box and magnetic coils calibrators.
- TEST for proper connection of electric and magnetic sensors
NORD receiver can estimate the contact resistance of each grounded electrode separately and has the ability to measure the overall electric lines response functions, which include the complex effects of wires and electrodes. This allows taking unbiased electric field measurements even in the regions with poor grounding conditions.
When making a new instrument, we were resting upon more than 25-year experience of our company in carrying out field electromagnetic exploration and scientific reasearch. The vast experience of EM surveying in severe Arctics, Bolivian mountains, Iranian deserts and northern seas dictated the following requirements for the novel EM logger:
All of these requirements have been successfully embodied in NORD receiver!
- high reliability and accuracy of the acquired data;
- small size and weight, low power consumption;
- compatibility with widely used MT equipment of other manufacturers.
All of these requirements have been successfully embodied in NORD receiver!
Andrey Yakovlev, Ph.D.
Nord-West Ltd., CEO
NORD Project Manager
NORD Project Manager
Field tests
NORD system is being tested in field conditions since 2014, and, starting from 2017, dozens of pilot instruments are continuously used in commercial MT and CSEM projects in Ural Mountains, Taymyr Peninsula, Western Siberia and Kazakhstan.
Thousands of performed measurements have already proved that NORD — is an accurate and reliable field instrument, perfectly suited for commercial projects.
Thousands of performed measurements have already proved that NORD — is an accurate and reliable field instrument, perfectly suited for commercial projects.
Key features
of NORD receiver
- HIGH ACCURACYHigh accuracy of the acquired MT or CSEM data is ensured by low internal noise level (~ 3.5 nV/√Hz) and modern ADCs of NORD receivers, combined with using the state-of-the-art data processing algorithm implemented in the EPI-KIT software.
- QUICK STARTNORD is ready to start a GPS-synchronized record just about 10−20 s after it is turned on (provided that the previous record was taken in the same region). In many cases this feature may significantly increase the production rate of a field crew.
- REAL-TIME PROCESSING, EASE OF OPERATIONWithout interrupting the record, you can process data in real time and view the actual input signals at any given channel. The receiver could be controlled even from a smartphone. NORD is equipped with a number of internal sensors, allowing the user to monitor the power-supply current and voltage, temperature of ADC and processor, etc. These features are very useful and may largely decrease the amount of rejected data.
- WIRELESS CONNECTIONDevice control and status monitoring, as well as data processing, management and transferring to and from NORD is implemented by wireless network. High-speed Wi-Fi connection allows downloading an average overnight MT record (50−70 MB for conventional schemes of signal sampling) within several seconds. Connection with NORD could be easily established either from a PC or a smartphone. All you need is that your device has Wi-Fi module and a web browser.
- EXTENDED WARRANTYLarge amounts of field data acquired by Nord-West during the commercial projects in Ural Mountains, Taymyr Peninsula, Western Siberia and Kazakhstan have shown that NORD is a robust and reliable field instrument.
Our confidence in its reliability allows to extend the no-cost warranty period up to 2 years. - EXTENDED SUPPORTWe understand that for most users of geophysical equipment
the continuity of once initiated field operations is essential. Therefore we may offer to our customers the extended worldwide support of the purchased receivers, including
a prompt assignment of our specialist for fixing up the equipment on site or replacement of nonoperating units until they are repaired. - SMALL SIZE AND WEIGHT, LOW POWER CONSUMPTIONNotwithstanding the rugged design and metallic encasing, NORD is very compact and weighs just about 1.8 kg. Small size of the instrument makes its manual transportation much easier. Low power consumption allows using a smaller lightweight battery for its power supply, or working with a standard 60Ah battery for several days.
- COMPATIBILITYAn important feature of NORD is the general possibility of its using along with the MTU-5/2E/3H, MTU-5А/2EA and V8 receivers manufactured by Phoenix Geophysics. NORD is capable of working directly with the MTC sensors, and may be employed together with the MTU units as well — for instance, the records from one type of receivers may be used for remote reference processing with those from another type.
Field sensors
magnetic field sensors
NORD system delivery set includes induction coils of IMS series — low-noise magnetic field sensors with smooth and stable frequency characteristics.
Induction sensors IMS-005 are supplied with high-frequency receivers NORD-A and are designed to perform the Audio MT records in frequency range from 1 to 20000 Hz. Also, IMS-005 sensors in pair with low-frequency IMS-010 sensors can be supplied with NORD Plus broadband receivers.
Induction sensors IMS-010 are supplied with NORD receivers and are designed to perform MT records in the frequency range from 0.00002 to 1000 Hz. These sensors cover the "classic" frequency range for MT and have high sensitivity at low frequencies and in the MT dead band.
Induction sensors IMS-015 are supplied with NORD Plus receivers and, in comparison with the IMS-010, have a range extended to higher frequencies: from 0.00002 to 10000 Hz. One record of the NORD Plus receivers with IMS-015 sensors allows obtaining a single AMT-MT curve without changing the recording mode and connecting different types of sensors.
Technical specifications
of IMS induction coils
| Parameter | IMS-005 | IMS-010 | IMS-015 |
|---|---|---|---|
| Operation frequency range, Hz | 1÷20000 | 0.00002÷1000 | 0.00002÷10000 |
| Output sensitivity: linear growth, V/(nT·Hz) constant amp., V/nT | 0.2 < 5 Hz 0.8 | 0.7 < 2 Hz 1.6 | 0.7 < 2 Hz 1.6 |
| Max. output voltage, V | ± 10 | ± 10 | ± 10 |
| Power supply voltage, V | ± 15 | ± 15 | ± 15 |
| Power consumption, W | 0.96 | 1.2 | 1.7 |
| Dimensions: length, cm | 55 | 105 | 105 |
| Dimensions: diameter, cm | 6 | 7.5 | 6 |
| Weight, kg | 3 | 7 | 5.5 |
Years of testing and improvement of the IMS coils allowed to produce magnetic field sensors with unique operational characteristics.
The sensors are calibrated at a certified stand and have a calibration certificate. The sensors also have a built-in calibration system for express field calibration.
Warranty period for the IMS sensors is 2 years. The coils are supplied in a leak-proof transportation case.
electric field sensors
For electric field measurement we offer graphite electrodes NW-4. NW-4 is a compact, environmentally sound and relatively unexpensive non-polarizable electrode with low self-noise level.
Amplitude-frequency characteristic of NW-4 electrodes
Technical specifications
of non-polarizable graphite electrodes NW-4
| Parameter | Value |
|---|---|
| Potential difference between two electrodes | < 5 mV |
| Self-noise level at frequencies 0.0001-0.1 Hz | < 0.5 mV |
| Self-noise level at frequencies 0.1-10000 Hz | < 0.2 mV |
| Assured storage period | 24 months |
Data processing
For processing of the raw time series acquired by NORD system one should use EPI-KIT — a modern and universal software solution for processing of MT and CSEM data.
“
In the present-day MT exploration, the choice of software support is equally important as that of the hardware. There are a lot of MT data processing programs in the global market to date, which are mostly developed for the academic or scientific purposes, and are intended for working with some certain type of the MT instrumentation.
The EPI-KIT software has been developed as a powerful and universal tool of the MT and CSEM data processing on a commercial scale.
Apart of the NORD data files, EPI-KIT is able to handle the time series acquired by MT loggers of many other manufacturers, including Phoenix Geophysics, Metronix and LEMI. Due to the compatibility of the NORD sampling patterns with those of the other receivers, it is possible to employ the equipment of different manufacturers together in a single project, e.g., at both survey and remote reference sites.
The EPI-KIT software has been developed as a powerful and universal tool of the MT and CSEM data processing on a commercial scale.
Apart of the NORD data files, EPI-KIT is able to handle the time series acquired by MT loggers of many other manufacturers, including Phoenix Geophysics, Metronix and LEMI. Due to the compatibility of the NORD sampling patterns with those of the other receivers, it is possible to employ the equipment of different manufacturers together in a single project, e.g., at both survey and remote reference sites.
EPI-KIT features
Adaptive processing algorithm. At the bottom of the EPI-KIT software there is a solid mathematical kernel based on the correlation method and robust statistics. After years of research and hands-on experiments we have developed a novel
adaptive algorithm of data processing, which employs a separate approach for estimation of any given transfer function.
Rapid computation. The implemented code supports the technology of parallel computation on graphical accelerators (GPU), which significantly reduces the processing time. The optimized computational routine and memory allocation allows working with the EPI-KIT software both on simple laptops and powerful multi-core computing systems.
adaptive algorithm of data processing, which employs a separate approach for estimation of any given transfer function.
Rapid computation. The implemented code supports the technology of parallel computation on graphical accelerators (GPU), which significantly reduces the processing time. The optimized computational routine and memory allocation allows working with the EPI-KIT software both on simple laptops and powerful multi-core computing systems.
User-friendly interface. The EPI-KIT interface is practical and simple, and it has many useful tools for the analysis and efficient processing of large amounts of field data:
- interactive map, indicating the survey site locations;
- visual table for previewing and editing the acquisition parameters of the recorded data;
- record (time series) visualization tool, with an option of excluding specified time intervals from processing;
- a tool for analysis of the spectral and correlational characteristics of the acquired records;
- preview and comparison of the equipment calibration measurements taken at different times;
- creation, enqueueing and management of the various processing tasks;
- express review of the data processing results.
Apart of the NORD data files, EPI-KIT is able to handle the time series acquired by receivers of other manufacturers, such as Phoenix Geophysics, Metronix and LEMI. The EPI-KIT software is able to make a cross-processing of NORD and all series of models MTU including the MTU-5C receiver data with same sample rate, that means, it is possible to make the remote reference processing of NORD data with MTU-5C reference base.
https://epi-kit.ru
There is a standalone web site, where one may learn more about basic features and capabilities of the EPI-KIT software, as well as view a short video tutorial.
Other MT software
Nord-West has developed a series of dedicated software solutions for processing, analysis and interpretation of magnetotelluric data
InversiO
Software for analysis and 1D/2D interpretation of MT data
VIDEO
NORD system: cruciform MT layout
Delivery set
The typical delivery set for the NORD system includes:
- NORD receiver in a carrying case with a power-supply cable, GPS and Wi-Fi antennas;
- A set of 3 induction coils IMS-015 with 3 corresponding cables in a carrying case. OR a set of 3 induction coils IMS-005 and a set of 3 induction coils IMS-010 with 3 corresponding cables in a 2 carrying cases;
- Non-polarizable graphite electrodes NW-4 (40 pcs);
- Copper cable for electric dipoles (250 m);
- Fieldwork instrumentation kit (tester, compass, level);
- EPI-KIT software for MT and CSEM data processing;
- MT-Corrector software for post-processing and editing of processed MT data.
Contact us
To request the price or ask any other question related to the NORD system, please, use the form below.
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NORD, EPI-KIT and MT-Corrector copyright belongs to Nord-West Ltd.
For purchase NORD and technical support please contact
mail@nw-geophysics.com
For purchase NORD and technical support please contact
mail@nw-geophysics.com
