APS’s Azimuthal Gamma Ray (AZG™) Sensor enables accurate geosteering by adding imaging capabilities to existing APS measurement while drilling/logging while drilling (MWD/LWD) measurements. This new sensor is designed specifically for low power consumption and is backward compatible with APS’s MWD/LWD systems, including the WPR™ resistivity sensor.

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This system provides protection against the high levels of shock and vibration experienced during drilling, while providing maximum measurement sensitivity to the formation.

  • Can be programmed to acquire gamma ray data in up to 24 azimuthally sectored bins around the borehole, as well as provide a total gamma ray measurement.
  • Binned data and total gamma data are both recorded in memory and telemetered to the surface for real-time steering decisions.
  • Capable of providing a calibrated, API-standard gamma ray response.
  • A wellsite check source is available to ensure proper pre/post run operational performance, both for use in the field and at the maintenance facility.
  • Easy-to-use SureLog surface system scales the gamma ray readings to API units, correcting for borehole size, mud weight, collar effects and KCl content of the drilling fluid. Capable of displaying both the total gamma ray log and the gamma image log in real time and as memory log plots.
  • In addition to the log plot displays, the surface system provides user-defined hard copy output logs.
  • Data can be exported in standard log copy formats such as WITS, LAS and ASCII.

  • Available sizes: 4.75 and 6.75 in. (121 and 171 mm).
  • Employs three ruggedized, shielded gamma ray detectors with photomultiplier tubes along with a directional package.
  • Mounted in a specially designed, collar-based system, providing protection against the high levels of shock and vibration experienced during drilling along with maximum measurement sensitivity to the formation.

  • Geosteering


Tool OD 4.75 and 6.75 in. (121 and 171 mm)
Sub Length 88 in. (2235 mm)
Measure Point ~ 30 in. (762 mm) from downhole end
Sensors 3 NaI scintillation detectors with PMTs
Measurement Range API API-calibrated 0 – 800 API ±3 API @ 100 API
0.8 cps API per detector
Data Sampling Rate Programmable, in up to 24 bins
Vertical Resolution 6 in. (152 mm)
Maximum Temperature 302˚F (150˚C) and 347˚F (175˚C)
Maximum Pressure 20,000 psi (137.9 MPa)