Geophysical Tem Survey Equipment Electric Magnetic Time Domain Transient Electromagnetic Instrument 500m 1000m Depth Tem System for Deep Exploration Instrument
Transient electromagnetic method (TEM) is a method of detecting dielectric resistivity by transmitting a primary pulsed magnetic field to the underground by an ungrounded loop or grounded wire source, and observing the secondary induced eddy current field in the underground medium by coils or grounded electrodes during the interval of the primary pulsed magnetic field. Its basic working method is to set up a launching coil with a certain waveform current on the ground or in the air, so as to generate an electromagnetic field in the surrounding space, and generate an inductive current in the underground conductive rock orebody: after power failure, the inductive current decays with time due to heat loss.
Deep TEM Exploration System
Medium-Deep/Deep TEM Exploration System is applicable to medium-deep/deep transient electromagnetic exploration, one of our latest researches, with all functions of transient electromagnetic survey system. It boasts high power, short turn off time, high reliability, strong anti-interference performance (against atmospherics, 50Hz or 60 Hz industrial frequency interference), lightweight and low power consumption.
Transient electromagnetic detection has the following advantages
(1) Because of its high construction efficiency, pure secondary field observation and sensitivity to low resistivity, it has become the preferred method in the current hydrogeological exploration of coalfields.
(2) Transient electromagnetic method (TEM) is the most sensitive method to find low resistivity geological body in high resistivity surrounding rock, and it has no topographic influence.
(3) Using the same point combination observation, it has the best coupling with the detection target, strong abnormal response, simple shape and strong resolution.
(4) Profile survey and bathymetry are completed simultaneously to provide more useful information.
| |
Transmitter |
| Transmitting voltage |
≤200V |
| Transmitting current |
≤50A |
| Current measurement precision |
current range before power supply being cut off is 0~50A, display resolution is 0.01A. |
| Power supply frequencies |
0.0625Hz, 0.125Hz, 0.25Hz, 0.5Hz, 1Hz, 2Hz, 4Hz, 8Hz, 16Hz, 32Hz |
| Transmitting waveform |
+ON, OFF, -ON, OFF, equal width and dual polarity |
| Turn-off delay time |
1μs~1000μs |
| Turn-off time |
≤1.2μs (pure resistance), changing with the transmitting current and transmitting coil when connecting to the coils |
| Damping resistance |
1000Ω |
| Transmitting coil |
0.1km×0.1km single turn ~ 2km×2km single turn |
| Synchronization mode |
external synchronization (cable, GPS) |
| Power supply |
internal 12V8.6Ah rechargeable battery (or external 12V power supply) lasting for over 10 hours |
| Dimension |
525×436×217mm 3 |
| Weight |
18.5kg |
| Working temperature |
-10°C~+50°C |
| |
Receiver |
| Number of channel |
1 |
| Pre-amplification gain |
8, 32 times |
| Main amplification gain |
1, 2, 4, 8, 32, 64, 128 times |
| Band-pass |
0~50k Hz (liner phased filter), full band-pass 0~400k Hz |
| Suppression |
80dB |
| A/D |
16 bit |
| Min sample interval |
1μs |
| Trace number |
≤128 |
| Stacking times |
1~9999 time |
| Synchronization mode |
internal 12V9.6Ah rechargeable battery (or external 12V power supply) lasting for over 10 hours |
| Pocket PC |
Windows Mobile 6.0 system with software such as Word, Excel, etc., 320x240 true color, 64MB Flash Rom/ 64MB SDRAM/64MB 2GB CF card, able to store over 200,000 readings of sampled data,2 original rechargeable batteries |
| Ports |
Bluetooth, infrared and serial port |
| Dimension |
340×295×152mm |
| Weight |
5.3kg |
| Working temperature |
-10°C~+50°C |
In reality, TEM plays a very important role in hydrogeological exploration, and its exploration results are feasible and effective. The exploration depth of this method is relatively large, the resolution ability is also very strong, is affected by the topography is relatively small, the work efficiency can be fully guaranteed, can provide a very reference for hydrogeological exploration clues. In some engineering construction, hydrogeological structure at a certain depth needs to be investigated in detail to know whether there is underground river, so as to ensure the safety and stability of the project. Transient electromagnetic method can solve this problem better. However, due to the complexity of the exploration of the underground river and the MULTI-resolution of the geophysical data, it is necessary for us to comprehensively interpret and analyze the anomalies from different angles to improve the accuracy of the exploration. At the same time, the comparative analysis results between this method and other methods show that there are still two problems to be solved when using WTEM-2 transient electromagnetic instrument for exploration. One is that the exploration results suppress the shallow bottom information relatively large; Second, the AC apparent resistivity of the survey results is generally low.
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