Unlike Magnetic MWD survey tools that are influenced by the magnetic environment, Gyro is not affected by magnetic interference. It can be run inside casing, tubing, drill pipes and magnetically disturbed ground, also for high temperature applications including surveys of geothermal wells, gyro probes protected in a heat shield are available.

PKOK’s continuous North Seeking Gyro tool is an advanced, rugged, reliable and accurate down-hole measurement tools designed for the oil and gas wells.

The PKOK Gyro package comes with both wire line and memory mode option. The Wire line mode is run from an electric line cable transmitting real time data to the computer at the surface. Memory mode is fast and cost efficient as this is powered by battery supply and run on slick line

Features and Benefits

  • Not affected by magnetic interference
  • No field calibration or roll test required before each survey
  • Collar azimuth not required. Only latitude of hole needs to be entered into the software program
  • No sight alignment is required
  • Can traverse in hole at up to 120m/min
  • Package includes both wire line and memory mode
  • Short length, light weight tool
  • User friendly software
  • Very accurate and reliable
  • Possible to calibrate at customer facilities
  • Rugged design
  • Minimal downtime as all operating equipment and software is very reliable
  • All azimuth measurements are in reference to geographical north


  • Gyro compassing survey time of 55 seconds
  • Azimuth accuracy of +/- 1.0° Repeatability in azimuth +/- 0.5°
  • Inclination accuracy of +/- 0.1°
  • Gravity toolface accuracy of +/- 0.1°
  • Gyroscopic toolface accuracy of +/- 1.0
  • Temperature rating: -30°C to +100°C (-22°F to +212°F)
  • Pressure rating: 15.000psi
  • Quartz technology accelerometers


  • OD 42mm (1.65″)
  • Length 2300 mm (90.55″) for Wire line mode, 2000 mm (78.74″) for Memory mode
  • Weight 15 kg (33,07 lb

Gyro Surveys

A gyro survey device is a device that is set spinning and oriented toward true north. A north seeking gyro is contained in the slim tubular device seen above. It is initialized and sent down into the casing and well bore. The “gyro hand” or wireline survey operator stops at various depths from surface to the bottom of the well taking surveys. A gyro is able to indicate the direction in which it is oriented based on the principle of conservation of angular momentum. Because of this effect a north seeking gyro is immune to interference from magnetic fields.

The wireline survey tool is able to record the azimuth or compass direction that the well bore is pointing, as well as the inclination. Using this data a profile of the well can be created. The job of the wireline survey operator must be performed precisely and accurately or else there could be serious legal issues, such as crossing into another oil companies lease or colliding with another well. There are cases where bad surveys cost oil companies millions of dollars when it was found a well had crossed a lease line.

Wireline survey equipment is also used to orient devices placed down the well bore, such as a whipstock

Multishot Surveys

A technique for determining the deviation of a wellbore. The multishot tool provides more accuracy than the single-shot tool and is usually used in highly deviated wells.

SingleShot Surveys

A technique for acquiring deviation information from a borehole on a slickline. In high-angle wells, a multishot technique is usually used instead.