Well Tool Position Sensor with Viscoelastic Damping
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Solution Overview
Problem
Existing position sensors for well tools face challenges in accurately determining the configuration and position of closure assemblies in harsh wellbore environments, due to factors like vibration, temperature extremes, and the need for reliable and efficient signal stabilization.
Innovation Solution
A position sensor design incorporating a support device made of shape memory alloy, a damping device with viscoelastic material, and a resistive element with contacts that displace across the element to indicate position through resistance changes, including spikes and gradual resistance variations, while maintaining stable electrical signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a position sensor is used in a harsh wellbore environment, then position measurement capability is provided, but the sensor components are subjected to vibration, shock, and temperature extremes that can damage the sensor and destabilize signals
Solution Approach 1:
A damping device incorporating viscoelastic material is positioned between the indicator portion and the housing to cushion and dampen vibration and shock before these forces can damage the sensor components. This beforehand cushioning protects the fragile indicator portion from harmful mechanical forces while allowing the sensor to continue functioning in the harsh wellbore environment.
2Reliability
If the indicator portion is made more robust to withstand harsh conditions, then reliability improves, but the electrical signal stability may be compromised due to increased mass and reduced responsiveness
Solution Approach 1:
The damping device provides beforehand cushioning that protects the indicator portion from vibration and shock without requiring the indicator itself to be more massive or robust. This allows the indicator to remain lightweight and responsive while still protecting it from environmental hazards, thereby maintaining electrical signal stability.
Solution Approach 2:
The damping device acts as an intermediary element between the harsh external environment and the indicator portion. It absorbs and dissipates mechanical energy from vibration and shock, preventing these forces from directly affecting the indicator and its electrical signal generation, thus maintaining signal stability while allowing the indicator to remain delicate.
3Stability of the object's composition
If damping material is added to reduce vibration effects, then signal stability improves, but device complexity increases
Solution Approach 1:
The damping device utilizes viscoelastic material that can be configured as a thin film or shell-like structure. This flexible damping material provides effective vibration damping and signal stability while adding minimal structural complexity compared to rigid damping mechanisms. The thin-film approach allows the damping function to be integrated seamlessly into the existing sensor architecture.
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
The solution provides accurate and reliable position sensing with enhanced resistance measurement capabilities, improved signal stability, and temperature indication, reducing damage from shock and vibration, and simplifying the measurement system by using redundant resistance readings.
Implementation Method 1
A support device is made of a shape memory alloy for supporting the carrier
Implementation Method 2
The damping device may include a viscoelastic material in contact with the contact
Implementation Method 3
A change in position of the contact relative to the resistive element is indicated by a resistance change as the contact displaces across the resistive element
Data Source
AI summary
A position sensor for well tools. A position sensor includes an indicator portion including a carrier supporting a resistive element and at least one contact, and a support device for supporting the carrier. Another position sensor includes an indicator portion including a slider for displacing at least one contact relative to a resistive element, the slider being displaceable between first and second limits, and an end load mechanism including a biasing device which exerts a biasing force on the slider as the slider approaches at least the first limit. Another position sensor includes an indicator portion including a resistive element and at least one contact which contacts and displaces across the resistive element, a change in position of the contact relative to the resistive element being indicated by a resistance change as the contact displaces across the resistive element.