Geosciences
Electromagnetic Methods in Exploration
A programme in frequency-domain and time-domain electromagnetic surveying: induction principles, ground conductivity instruments, transient electromagnetic soundings, survey planning, data processing and inversion, and applications in groundwater, the environment and mineral exploration, including joint inversion of resistivity tomography and transient electromagnetic data.
Overview
About the programme
Duration
3 days
Delivery
Training room with field work
Language
Arabic or English
Objectives
Training outcomes
- Understand electromagnetic induction, primary and secondary fields, and skin depth.
- Distinguish frequency-domain (FDEM) from time-domain (TEM) methods, and choose the method and configuration for the target and depth.
- Plan and carry out ground conductivity and transient electromagnetic surveys, and deal with sources of noise.
- Process the data, run 1D inversions and build pseudo-2D sections.
- Integrate the results with resistivity and borehole data, and understand the principle and limits of joint inversion.
Content
What the programme covers
Day 1: principles and frequency-domain methods
- Electromagnetic induction, conductivity and resistivity, and skin depth as a function of frequency and conductivity.
- Ground conductivity instruments: coil spacing and orientation, depth of investigation, apparent conductivity and the in-phase component.
- Mapping applications: salinity plumes, landfill leachate, and buried pipes and metallic objects.
Day 2: time-domain methods
- The transient electromagnetic principle: transmitter loop, current turn-off, the decay curve, and early and late time windows.
- Central-loop, coincident-loop and separate-loop configurations; choosing loop size and transmitter current for the target depth.
- Noise: power lines, fences and metal pipes, stacking, and the effect of induced polarisation on transient data.
- Airborne electromagnetic surveys and their use in regional exploration.
Day 3: processing, inversion and integration
- Processing decay curves, removing noisy windows, and 1D inversion with layered and smooth models.
- Pseudo-2D sections and depth-slice maps.
- Joint inversion of resistivity tomography and transient electromagnetic data: the principle and the gain in resolution near the surface and at depth.
- Case studies: fresh and saline aquifers and conductors in massive sulphide exploration, followed by the assessment.
Who it is for
Target audience
Geophysicists, geologists and hydrogeologists, mineral exploration teams, and environmental engineers working on contamination monitoring and saline intrusion.
Method
Delivery method
Theory with field practice on a ground conductivity instrument and a transient electromagnetic sounding, depending on the equipment available, followed by processing and inversion on the computer. Equipment and the practice site are agreed with the organisation before delivery. Delivered in Arabic or English.
Questions
FAQ
Is the programme suitable for someone who has not used electrical methods?
Yes. It starts from the principles of electromagnetic induction; familiarity with basic resistivity concepts helps, particularly in the joint inversion session.
Does the programme cover airborne electromagnetic surveys?
It presents their principles, applications and the first-pass interpretation of their outputs, but does not cover operating airborne systems.
Can the examples focus on our sector?
Yes. Case studies can be directed towards groundwater, the environment or mineral exploration according to the organisation’s work, and its data used in the exercises if it arrives before delivery.
A programme tailored to your organisation
The duration and topics of the programme are adjusted to the organisation's needs, and it is delivered at its site, in a training hall arranged by the Center, or virtually.