Ruggedised Automatic Gauge for Wireline Intervention

The Reservoir Group Sentinel is an extremely rugged downhole pressure and temperature gauge designed to be run as part of any wireline string. A true user friendly ‘Run-it-yourself’ gauge contained in a bespoke spring mounted shock absorbing assembly, the Sentinel is fully automatic and requires no operator input to acquire data.

The Sentinel is supplied in monitor mode, a non-recording mode, where it is checking pressure and temperature readings every two minutes. When a user-programmed temperature or pressure threshold has been exceeded, the Sentinel automatically enters record mode and stores data to memory at a pre-set sample rate. At the end of a survey, the Sentinel stops recording automatically when pressure and temperature readings fall below the user-programmed threshold values. The Sentinel then reverts to monitor mode ready for the next survey.

A large 1,000,000 data set memory and a built in real-time-clock allows real-time storage of data, in individual survey data files, so that every survey is easy to identify. Multiple wireline surveys/drift runs are possible on a single long life AA size battery. A gradient/BHP survey can be performed during any drift run with no additional rig time or wireline operations.


  • Completely automatic, no operator input required to record data
  • All data is stored with real time values for easy analysis
  • 1,000,000 data set memory, where 1 second recording rate provides 11.5 days of data
  • Innovative electronics dramatically reduces power consumption
  • Long life ‘AA’ size battery is easier to ship since it is not classed as dangerous goods
  • Overall length of 19” and 1-1/16” SR thread connections makes Wireline rig- up easier
  • Spring mounted gauge, can be run with perforating guns
  • Gradient surveys
  • Perforation monitoring
  • Pressure build-up or draw-down tests
  • Production surveys
  • Reservoir evaluation, well testing & DST
  • Static, flowing and build-up surveys
  • Stimulation monitoring



Maximum external pressure Must not exceed sensor range or 15 ksi Max
Sensor range 2 options, 8.6 ksi and 15 ksi
Sensor type Piezo-resistive
Accuracy ± 0.06% FSO
Accuracy typical
± 0.04% FSO
0.2 psi
Maximum temperature
Must not exceed 150°C
Operating range
0 to 150°C
± 1.0°C
Accuracy typical
± 0.5°C
Battery type
AA type lithium, hardwired
Operating voltage
3.6 to 3.9 V
Battery life*
Up to 1 Year
Sampling interval 1 to 600 seconds
Memory type Non-volitile
Capacity 1,000,000 data sets
Record contents
Real time, pressure, temperature
Diameter options 1 1/16" sucker rod
Materials SS 17-4 PH, Sub K500 Monel
Standard or H2S