Gyrodata’s 1.75-inch OD rate-gyroscopic survey system provides precise orientation of whipstocks, packers, drilling assemblies, perforating guns, logging tools and borehole geophones.
Gyrodata’s rate-gyroscopic survey technology marked a major advancement in the ability to orient drilling assemblies and other downhole tools and instruments.
‘No more 180 out!!’
“180 degrees out” is a phrase heard often when orienting whipstocks and drilling assemblies the old way with free gyro systems – a practice still being conducted in some areas.
Free gyro tools require a physical orientation of the gyro before the run, which is subject to human error and which often leads to large errors downhole. Free gyros also drift off their initial orientation during the run, leading to additional error.
Errors with free gyros also increase with depth and time, since drift increases. As orientation work goes deeper in such operations as re-entry, the feasibility of using free gyros is lessened significantly.
As a result of these errors, many wells have been drilled in the wrong direction using free gyros to orient whipstocks and drilling assemblies. While correcting for these problems can be costly, it can also be disastrous if the error causes a collision with an adjacent wellbore.
Gyrodata’s rate-gyro system eliminates the problem of large orientation errors associated with free gyro systems.
- The dual-axis rate-gyro requires no physical orientation at surface like a free gyro.
- A rate gyro has no drift downhole like a free gyro.
- A rate gyro has no depth or time dependant errors
Gyrodata Rate Gyro Advantages
Gyrodata’s inertial-grade, dual-axis, drytuned rate-gyros provide higher precision for orientation work and offer advanced operational capability. The dual-axis gyro calculates a survey point without rotating the sensor. A single-axis rate-gyro must rotate the sensor to calculate a survey point, which is less accurate.
Higher Heat Capacity !!!
Gyrodata’s dry-tuned rate gyros can withstand much higher temperatures than fluid-filled gyros. In fact, Gyrodata’s system rovides the highest heat capacity versus time of any small diameter gyro system. While other tools use costly rigtime pulling out to cool off, Gyrodata’s system can survey to 300°F with no time restraints. A record 31 hours was logged in the Austin Chalk at 146°C with the 1.75-inch steering gyro probe.
The highest possible orientation accuracy of directional drilling assemblies is achieved with rate-gyro systems. A muleshoe stinger at the bottom of the survey probe lands in a orienting placed above the MWD and motor.
Along with the increase in horizontal drilling and re-entry operations, rate-gyros are being used routinely throughout the world to orient the whipstock/packer assemblies prior to drilling out of the casing window.
Rate-gyros can be run on wireline in conjunction with perforating guns to provide orientation of the gun.
While usually run in combination with logging instrumentation for depth correlation and to save time, rate-gyros are also run to define the orientation of logging sensors.
Rate-gyros are often required in borehole seismic operations when tri-axis geophones are employed in Vertical Seismic Profiling. Typically, the rate-gyro is connected to the bottom of the geophone to provide axis orientation at each level in the well and also to survey the well in the same run.
Rate-gyros can be run to provide the orientation, direction and inclination, of subsea wellheads and templates.
|Type||RGS Orientation (RGS-OR)|
|Sensor Performance||±0.05° Inclination, ±0.1° Azimuth, ±0.05° Tool face (1 sigma)|
|System Performance||SPE WPTS approved models|
|Inclination Range||0-120° with pump down capability|
|Tool Length||10-22ft (3-6.7m) average|
|Max Survey Speed||Up to 300ft/min (92m/min) depending on well conditions|
|Tool Weight||66-275lbs (30-125 Kg.)|