1. n. [Formation Evaluation]

A qualitative description of the roughness of a borehole wall. Alternatively, the term pertains to a borehole whose diameter changes rapidly with depth. The term usually refers to changes at the scale of logging measurements, a few inches to a few feet, and to the effect this has on logging tool responses. Rugosity can be observed on caliper logs, image logs and by its effect on measurements with a small depth of investigation.

See: bad hole