Name three main physical properties of rocks which are not logged by wirelines.

• A. Electrical, nuclear, acoustic
• B. Magnetic, thermal, optical
• C. Porosity, permeability, density
• D. Color, texture, grain size

Answer: (A)

The key idea is that borehole wireline logs capture rock properties that affect how signals travel through the rock—electrical behavior, radioactive response, and acoustic travel times. Visual features like color, texture, and grain size aren’t measured by these downhole sensors. They require direct observation of the rock surface or thin sections in a lab, obtained from cores or cuttings, not from a downhole probe.

So the three rock properties not logged by wirelines are color, texture, and grain size. The other options include properties that wireline tools do measure or help infer (electrical, nuclear, and acoustic; or density/porosity inferred from logs), or involve measurements that aren’t standard downhole logs.