Centrifugal Counterweight Downhole Actuator for Deviated Wells
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Solution Overview
Problem
Existing downhole actuators face challenges in maintaining consistent performance in deviated wellbores, particularly in diverting fluid flow efficiently and managing fluid pressure during drilling operations.
Innovation Solution
A downhole actuator design utilizing counterweights balanced around the circumference of the body, activated by centrifugal force, which diverts fluid flow through alternate pathways and includes a closure device that can restrict or allow fluid passage, controlled by a linkage mechanism and a locking piston system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional downhole actuator design is used, then the device can control fluid flow in vertical wellbores, but the performance becomes inconsistent in deviated wellbores due to gravitational effects on the retaining member
Solution Approach 1:
The patent applies counterweight devices that rotate with the drillstring to generate centrifugal force, which acts as an artificial gravity opposite to the gravitational effect on the retaining member. This centrifugal force ensures the retaining member reliably engages with the drive mechanism regardless of wellbore deviation angle, thereby maintaining consistent actuator performance across vertical to highly deviated wellbores
2Quantity of substance
If the closure device is designed to completely close the bore, then fluid flow is fully restricted, but fluid pressure management becomes difficult during drilling operations
Solution Approach 1:
The closure device is designed with selective closure capability, allowing it to close the bore completely in some operational scenarios while providing restricted flow or partial closure in others. This local quality variation enables precise control over fluid pressure management during drilling operations, accommodating different operational requirements without compromising either flow restriction or pressure control
3Device complexity
If the actuator relies on gravitational force to operate the retaining member, then the mechanism is simple, but the actuator cannot maintain consistent operation across varying orientations in deviated wellbores
Solution Approach 1:
The patent transforms the actuation mechanism from gravity-dependent to centrifugal force-dependent by introducing rotating counterweight devices. This parameter change in the operating force mechanism maintains relative simplicity while enabling consistent operation across all wellbore orientations, as centrifugal force is generated by rotation rather than gravitational orientation
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 consistent fluid diversion and pressure management in deviated wellbores, allowing high-speed drilling with fluid circulation, reducing reliance on mechanical resets, and maintaining actuator stability across varying orientations.
Implementation Method 1
The counterweight devices are moved between the first and second positions by centrifugal force created by rotation of the body
Data Source
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AI summary
A downhole actuator typically for a downhole tool such as a valve, and typically for incorporation in a string of tubulars in an oil or gas well has a central axis with radially movable counterweights on opposite sides of the axis, which move radially outward to change the activation state of the actuator. The counterweights are supported by link arms which control the movement of the counterweights in response to centrifugal force created by rotation of the body, for example, during rotary drilling operations of the string. Radial outward movement of the counterweights typically transmits axial forces between sleeves at the upper and lower ends of the counterweights, so when the counterweights move radially outward, the upper and lower sleeves approach one another, which typically triggers the actuator.