Park position for a survey tool
AssigneeSchlumberger Technology Corporation
InventorsMakito Katayama, Julien Steimetz, Joffroy Dominique Daniel Urbain, Zainab Orooq
Life of this patent
Estimating the term…
Abstract
A gyroscope assembly is maintained in a park position during drilling activities. In the park position, a sensitive axis of a gyroscope in the gyroscope assembly is perpendicular or approximately perpendicular to a longitudinal axis of a downhole tool. Maintaining the park position during drilling activities reduces the drift bias caused by overloading the input signal of the gyroscope due to rotation of the downhole tool.
Claims20
A method for stabilizing a gyroscope assembly, comprising:
- rotating the gyroscope assembly to a park position of one or more predetermined park positions;
- rotating a downhole tool about a longitudinal axis, the downhole tool including the gyroscope assembly;
- while rotating the downhole tool, maintaining the gyroscope assembly in the park position;
- slowing or stopping rotation of the downhole tool;
- while rotation of the downhole tool is slowing or stopped, unparking the gyroscope assembly and obtaining a survey measurement with the gyroscope assembly;
- after obtaining the survey measurement, returning the gyroscope assembly to one of the one or more predetermined park positions;
- and
- resuming rotating the downhole tool.
A system for determining downhole direction, comprising:
- a housing having a longitudinal axis, the housing being rotatable about the longitudinal axis during downhole operations;
- and
- a gyroscope assembly, the gyroscope assembly including:
- an indexable shell;
- a gyroscope located in the indexable shell;
- and
- a drive shaft rotatable about the longitudinal axis, the drive shaft including:
- an arm member coupled to the indexable shell;
- and
- one or more counter arms that mass balance the drive shaft.
A method for stabilizing a gyroscope assembly, comprising:
- calibrating a gyroscope of the gyroscope assembly, wherein calibrating the gyroscope includes determining one or more predetermined park positions based on misalignment of the gyroscope;
- rotating the gyroscope assembly to a park position of the one or more predetermined park positions;
- rotating a downhole tool about a longitudinal axis, the downhole tool including the gyroscope assembly;
- and
- while rotating the downhole tool, maintaining the gyroscope assembly in the park position.
Dependencies are inferred from the claim text.