Electric logging provides information on which of the following?

• A. Drilling mud weight and bit wear
• B. Gas content and formation temperature
• C. Formation resistivity, porosity, water quality, and location of water-bearing zones
• D. Surface wind speed and rainfall

Answer: (C)

Electric logging uses downhole electrodes to measure how the surrounding rock and its fluids conduct electricity. The key reading is formation resistivity, which, when interpreted with knowledge of the rock type and pore fluids, lets you estimate porosity and infer fluid content. By comparing the resistivity of the formation with the resistivity of the pore water, you can gauge water quality (salinity) and pinpoint where water-bearing zones are located along the well path. In short, this method provides formation resistivity, a link to porosity, insight into water quality, and the depth locations of water-bearing zones. It doesn’t measure drilling mud weight or bit wear, nor does it directly measure gas content or formation temperature, or surface weather.