Compact Spectral Gamma Ray Tools


Provide spectral gamma ray service in vertical, highangle, and horizontal wellbores


  • Identifying clay-mineral composition, including heavy minerals
  • Identifying kerogen and total organic carbon to help determine sweet spots in unconventional wells
  • Differentiating between radioactive pay zones and shale
  • Identifying fractured zones that contain high uranium concentrations
  • Indicating formation permeability
  • Correlating well-to-well detail
  • Delineating the reservoir

Features and Benefits

  • Highly efficient and sensitive scintillation detectors in both the conventional spectral gamma ray (SGS) and Compact spectral gamma ray (CSG) tools provide accurate spectral analysis with high detail.
  • The SGS tool uses a conventional, large-diameter, high-resolution detector to maintain statistical accuracy.
  • The CSG tool uses a multi-detector composite measurement to maintain statistical accuracy.
  • The CSG has been ruggedized with patented shock protection for high reliability.
  • Multiple CSG tools can be deployed in a single run to reduce data acquisition times.
  • Both tools Pprovide fully characterized, high-resolution potassium (K), uranium (U), and thorium (Th) measurements for enhanced reservoir analysis.
  • Both tools Ffacilitate wireline and pipe conveyance in wellbores that large-OD spectral tools cannot log.
  • Both tools Pprovide improved pay zone identification and detailed well-to-well log correlation
  • Both tools Iincrease logging efficiency and reduce rig time.

Tool Description

Spectral gamma ray tools—the Compact™ spectral gamma ray (CSG) tool and the conventional spectral gamma ray (SGS) tool—measure total natural gamma radiation as well as quantities of potassium, uranium, and thorium, the three most common elements found in radioactive sands and shales. The total gamma ray logs produced by the tools can be used to determine stratigraphic location, for correlation, and in the calculation of porosity and any quantity that requires clay volume. The spectral component adds the ability to distinguish hot sands from shale, helps to identify organic carbon, and differentiates clay types—an important factor in the assessment of permeability.

The CSG tool can be deployed in wells where conventional wireline tools are ineffective, including horizontal and high-angle wellbores. The 2.25-in. outer diameter of the CSG tool enables advanced conveyance techniques in memory mode and enables use in small-diameter wellbores.

The SGS tool can be deployed in more conventional applications that do not require special conveyance considerations.