MWD Gamma Sensor with Environmental Monitoring


APS’s next-generation SureShot™ MWD natural gamma sensor employs a rugged scintillation counter and photomultiplier mounted in a specially designed package which provides protection against the high levels of shock and vibration encountered in the drilling environment. In addition, this extensively qualified new design offers environmental monitoring capability and lower power consumption, while maintaining back-compatibility with APS’s earlier sensor designs.

The easy-to-use SureShot surface system scales natural gamma ray data to API units; corrects for borehole size, mud weight and drill collar effects; assigns each point a depth from the depth tracking system; and plots both real-time displays and configurable hard copy logs. Data can be exported in standard industry formats (WITS and LAS).

Features & Benefits

  • Calibrated to API-standard units.

  • A wellsite check source is available to verify tool performance in the field or maintenance repair shop.

  • Can be programmed to send a combination of gamma ray and tool face data transmissions to allow logging while steering and sliding.

  • The SureShot MWD can store up to 32 MB of gamma data for retrieval during trips.

  • Built-in accelerometers measure axial and lateral vibration. Peak axial shock, lateral shock and temperature data are stored in on-board memory every 5 minutes, up to 5,000 hours. Information on the service history of the tool is also stored.
    in on-board memory.

  • Lifetime log data provides valuable information to evaluate the health of the tool, and to develop preventative maintenance cycles base on the actual operating environment over time rather than total downhole hours alone.

  • Vibration measurements can also be used to justify claims for repairs that are a result of out-of-spec drilling conditions.


  • A rotation sensor in the directional package enables the tool to optionally transmit only gamma ray data while rotating.