Universal Gamma Ray Tool


Providing formation gamma ray for volumetrics, well-towell correlation, reservoir delineation, and depth control


  • The universal gamma ray (UGR) tool is typically run in combination with other logging tools. It is an effective correlation device because it can be used in almost any borehole environment.
  • The tool operates in both openhole and cased-hole environments.
  • It is effective in water-based, air, synthetic, or oil-based mud systems.

Features and Benefits

  • Measures natural gamma radiation from a high-resolution scintillation detector
  • Indicates shale volume
  • Enhanced sensitivity accurately correlates depth between logging runs
  • Detects radioactive minerals for shale volume analysis

Tool Description

The Weatherford universal gamma ray (UGR) tool measures natural radioactivity in the borehole and is used for correlation and lithology evaluations.

Measuring the naturally occurring radioactivity of formations adjacent to the borehole, the UGR detects the radioactivity of shales and clays as well as the very low levels of radioactivity emitted from clean formations, such as sandstone and limestone.

In sedimentary rocks, the UGR can be used as a lithology indicator toapproximate shale content of each formation.

Gamma ray logs also are used to correlate depth between openhole and casedhole well logs and between logging descents.