Contents
- Description of new solid-state gyroscopic survey tool
- technology and results
- The combination of gyroscopic and magnetic survey data
- statistical estimation methods
- Re-assessment of well placement methods
- making the best use of available data
Vibratory gyroscopes
- Technology incorporates vibrating element with piezo-electric driver circuits
- In the presence of device rotation, a Coriolis force is generated which modifies the motion of the vibrating element
- Coriolis motion detected using piezoelectric or capacitive pick-offs to provide measure of applied turn rate
- The vibrating element of such sensors can take various forms such as a string, a hollow cylinder, a rod, a tuning fork, a beam or a hemispherical dome
- Such devices are generally classified under the heading of Coriolis vibratory gyros (CVGs)
- Performance
- Low performance sensors with bias stability of tenth’s of a deg/sec – small sensors for automobile applications
- High performance sensors with bias stability of hundredth’s of a deg/hr – wellbore survey application
The new gyro system
- Spinning mass Gyro While Drilling System
- 16.5 feet:
- Modem
- Power section
- Drive section
- Sensor block
- 16.5 feet:
- Solid state Gyro While Drilling System
- 3.2 feet
Combined gyroscopic/magnetic surveys
- The measurements generated by the gyroscopic and magnetic tools may be combined using statistical estimation techniques
- Key feature of this process: enhanced accuracy and reliability of CVG tools allows gyro surveys to be used as a reference
- Facilitates reduction/removal of potential sources of error in magnetic system
- in particular declination error, axial interference, the effects of magnetic mud
...
View the entire Presentation:
John Weston, Adrián Ledroz
Gyrodata Inc.