Geophysical well logging — 7-topic bundle

Before logging, a well is drilled. Once the drilling fluid (mud) is circulated to clean the hole, logging tools are lowered. These tools, called "sondes," contain sensors that interact with the surrounding rock and fluids. They measure properties like electrical resistivity, natural radioactivity, density, and acoustic travel time.

The data is transmitted to the surface, where it's recorded and displayed as a series of curves plotted against depth. Each curve represents a different physical property, and by analyzing them together, called "log interpretation," geologists and engineers can paint a detailed picture of the subsurface.