VII Electricity methods: theory Flashcards
What is the principle behind DC resistivity methods?
The principle involves introducing current into the ground and measuring the resulting potential differences to calculate apparent resistivity. Variations in resistivity help infer subsurface structures.
What are the main factors affecting resistivity in geomaterials?
Temperature, mineralogy, porosity, fluid type, fluid salinity, and the presence of clay significantly influence resistivity.
Why are electrode configurations important in resistivity surveys?
Configurations determine the depth and resolution of measurements. For example, Schlumberger arrays are suitable for deep soundings, while Wenner arrays are better for shallow surveys.
How is noise managed during data collection?
Noise is mitigated by avoiding cultural features (e.g., power lines), maintaining good electrode contact, and using signal processing techniques to filter out irrelevant data.
What are the advantages and limitations of 2D resistivity imaging?
Advantages include high-resolution subsurface profiles and cost-effectiveness for environmental studies. Limitations are data interpretation challenges and susceptibility to noise.
