Rheological Fluid Lock for Torque Transfer in Directional Drilling
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Solution Overview
Problem
In directional drilling, the 'point-the-bit' method faces challenges when the reference housing becomes stuck in the borehole, as it is not connected torsionally to the driveshaft, preventing effective torque transfer.
Innovation Solution
A rheological fluid is sealed between the driveshaft and the housing, which changes viscosity in response to an applied electric or magnetic field, allowing the driveshaft to couple torque to the housing through a solid-like state, enabling torque transfer even when the housing is stuck.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the housing is not connected torsionally to the driveshaft to enable free rotation, then the driveshaft can rotate freely within the housing, but the housing becomes stuck in the borehole and cannot transfer torque effectively
Solution Approach 1:
The patent employs a rheological fluid that can dynamically change its state between fluid and solid-like phases. When the housing is not stuck, the fluid remains in a low-viscosity state allowing free rotation. When the housing becomes stuck, the fluid transitions to a high-viscosity solid-like state to enable torque transfer, thus dynamically adapting to operational conditions.
Solution Approach 2:
The rheological fluid's viscosity parameter is changed in response to applied electric or magnetic fields. By controlling the field application, the system can switch between low-viscosity (enabling free rotation) and high-viscosity (enabling torque transfer) states, resolving the contradiction between free rotation and torque transfer capability.
2Reliability
If a rheological fluid is used to couple torque when housing is stuck, then torque transfer is enabled, but the device complexity increases due to field generator and fluid chamber requirements
Solution Approach 1:
The rheological fluid acts as an intermediary between the driveshaft and housing. Instead of direct mechanical connection, the fluid mediates torque transfer by changing its rheological properties. This intermediary approach enables torque transfer without complex mechanical coupling mechanisms.
Solution Approach 2:
The patent replaces traditional mechanical torque transfer mechanisms with a field-controlled rheological fluid system. The electric or magnetic field controls the fluid's viscosity, substituting complex mechanical coupling with a more compact field-based control system.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables dynamic coupling and decoupling of torque between the driveshaft and housing, facilitating the drilling process by maintaining shear in the direction perpendicular to the applied field, thus overcoming the sticking issue.
Implementation Method 1
A rheological fluid is sealed between the driveshaft and the housing, which changes viscosity in response to an applied electric or magnetic field
Implementation Method 2
changes viscosity in response to an applied electric or magnetic field
Implementation Method 3
a field generator coupled to one of the driveshaft or the housing and configured to generate a field through the rheological fluid
Data Source
AI summary
A rheological lock apparatus includes a fluid chamber formed within a housing between a pair of seals. The fluid chamber contains a rheological fluid. An inner surface of the housing has a first plurality of splines projecting into the fluid chamber and extending longitudinally along a longitudinal dimension of the chamber. A driveshaft extends axially through the chamber such that the pair of seals are sealed against the driveshaft. The driveshaft includes a second plurality of splines. A field generator is coupled to one of the driveshaft or the housing to generate a field through the rheological fluid during times when the housing is substantially immobile in a borehole.