کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
4739707 | 1641116 | 2016 | 6 صفحه PDF | دانلود رایگان |
• A sandwich-layered earth is modeled to obtain a relationship between the resolution of the B field and the exploration depth.
• A transmitter and receiver system in TEM was designed for the exploration of areas with thick low resistivity overburden.
• TEM measurement used by SQUID can detect both shallow and deep regions.
Exploration of areas with thick low resistivity overburden is still a challenge for time domain transient electromagnetic method (TEM). We report modeling of a sandwich-layered earth by simulating the B field response with different conductive target layer thicknesses, thus obtaining a relationship between the resolution of the B field and the exploration depth. A low temperature Superconducting Quantum Interference Device (SQUID) is an ideal sensor for measuring the secondary magnetic field B in TEM measurements, because its sensitivity of several fT/√Hz is independent of frequency. In our TEM experiments, we utilized two different coils as receivers, a simple SQUID system, and a large transmitter loop of 200 × 200 m2 to compare the detected decay curves. At some measurement points, a decay signal of more than 300 ms duration was obtained by using the SQUID. Apparent resistivity profiles of about 9 km length are presented.
Journal: Journal of Applied Geophysics - Volume 135, December 2016, Pages 243–248