Gas Watch III Gas Detection System

Dependable and unmanned gas detection


Built on NOV-patented technology, the M/D Totco™ Gas Watch™ III dual infrared system measures both methane (C1) and propane (C3) gases. Unaffected by oil-based mud, the Gas Watch III system measures only formation gasses, accurately pinpointing gas shows and their magnitude. Calculating the C1/C3 ratio can provide a valuable tool in identifying hydrocarbon characteristics, which aid in geosteering and reservoir characterization. Solid-state sensors eliminate the need for field calibration and are guaranteed for five years.

The new QGM trap's enhanced sampling function guarantees accurate air-to-gas mixture, which is critical in gas-ratio analysis and minimizes the effects of changing mud levels. Our new design eliminates motor seizure due to corrosive liquids and allows quick and easy maintenance, resulting in maximum uptime.

You can track all gas readings on the rig in conjunction with your normal RigSense™ Electronic Drilling Recorder (EDR) and access your data though the WellData™ information system.


  • Dual sensor detects C1, C3, and total gas
  • Hydrocarbon-specific sensors
  • Solid-state infrared technology
  • No filaments to change and operating range of -22 to 122 ºF (-30 to 50 ºC)
  • Integrates with the RigSense EDR


  • Speciation of gases aids in geosteering and hydrocarbon characterization
  • Identifies formation gases only and not impacted by oil-based mud
  • Eliminates sensors fading over time and remains calibrated longer
  • Requires minimal maintenance and provides strong dependability
  • Provides tracking of C1, C3, and total gas/ROP gas log on the rig
  • Gas Watch III Flyer

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