Devices, systems, and methods for downhole surveying
AssigneeSchlumberger Technology Corporation
InventorsEdward Richards, Ross Lowdon, Shady Altayeb Mussa, Makito Katayama
Life of this patent
Estimating the term…
Abstract
A drilling system may include a steering tool configured to engage a wellbore wall to direct an orientation of a toolface, the steering tool being rotatable about a rotational axis. A drilling system may include an azimuth sensor package, the azimuth sensor package including at least one of a multi-axis gyroscopic azimuth sensor rotatable about the rotational axis of the steering tool, a multi-axis magnetic azimuth sensor rotatable about the rotational axis of the steering tool, or an accelerometer azimuth sensor rotatable about the rotational axis of the steering tool.
Claims8
A method for drilling a subterranean wellbore, the method comprising:
- rotating a bottom hole assembly (BHA) in the subterranean wellbore to drill, the BHA including a roll-stabilized housing deployed in a drill collar and configured to rotate with respect to the drill collar, a triaxial accelerometer set, a triaxial magnetometer set, and a gyroscopic azimuth sensor deployed in the roll-stabilized housing;
- collecting azimuth measurements using the gyroscopic azimuth sensor;
- using the triaxial accelerometer set and the triaxial magnetometer set to make corresponding triaxial accelerometer measurements and triaxial magnetometer measurements while the BHA rotates;
- measuring a rotation rate of the drill collar while the BHA rotates;
- generating a toolface of the BHA using the azimuth measurements;
- generating an azimuth of the BHA using the toolface of the BHA, the triaxial magnetometer measurements, and the rotation rate;
- and
- determining an inclination of the BHA using the triaxial accelerometer measurements, wherein determining the inclination includes:
- detecting a change in the rotation rate of the drill collar;
- generating an eddy current compensation term using the change in the rotation rate of the drill collar and the triaxial magnetometer measurements, wherein the eddy current compensation term is generated from a change in an angle when the change in the rotation rate of the drill collar is detected, and wherein the angle is formed between gravity and magnetic field vectors in a cross axial plane of the drill collar;
- and
- inputting the inclination, the toolface, the triaxial magnetometer measurements, the eddy current compensation term, and a magnetometer bias into a Kalman filter to generate the azimuth and an updated magnetometer bias.
A rotary steerable system for drilling a subterranean wellbore, the rotary steerable system comprising:
- a roll-stabilized housing deployed in a drill collar, the drill collar configured to rotate with a drill string, the roll-stabilized housing configured to rotate independent of the drill collar while drilling;
- an azimuth sensor package;
- and
- a controller, the controller including memory and a processor, the memory including instructions that cause the processor to:
- collect gyroscopic azimuth measurements, accelerometer measurements, and magnetometer measurements using the azimuth sensor package;
- measure a rotation rate of the roll-stabilized housing while the drill collar rotates;
- generate a toolface of the drill collar using the gyroscopic azimuth measurements;
- and
- generate an azimuth of the drill collar using the toolface, the magnetometer measurements, and the rotation rate;
- and
- determine an inclination of the drill collar using the accelerometer measurements, wherein determining the inclination includes:
- detecting a change in a rotation rate of the drill collar;
- generating an eddy current compensation term using the change in the rotation rate of the drill collar and the magnetometer measurements, wherein the eddy current compensation term is generated from a change in an angle when the change in the rotation rate of the drill collar is detected, and wherein the angle is formed between gravity and magnetic field vectors in a cross axial plane of the drill collar;
- and
- inputting the inclination, the toolface, the magnetometer measurements, the eddy current compensation term, and a magnetometer bias into a Kalman filter to generate the azimuth and an updated magnetometer bias.
Dependencies are inferred from the claim text.