Downhole Tool Extendable Component Tilting Mechanism
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Solution Overview
Problem
Downhole tools used for formation evaluation in oil and gas wells often become stuck to the wellbore wall due to differential pressure, making it difficult and time-consuming to retrieve them, especially when the mudcake layer is disturbed during operations.
Innovation Solution
The design incorporates an extendable component with a drive element, abutment, flexible coupling, tilt arm, and contact head that tilts to reduce the surface area engaging the wellbore wall, allowing for a rolling motion to disengage the tool from the wall and retract it safely, utilizing a backup piston and probe assembly with similar mechanisms to facilitate disengagement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the extendable component is pressed against the wellbore wall to establish fluid communication with the formation, then formation measurement capability is improved, but the component becomes stuck to the wellbore wall due to differential pressure
Solution Approach 1:
The patent applies the dynamics principle by making the extendable component movable between extended and retracted positions. The component can be dynamically adjusted based on operational needs - extended for formation measurement and retracted for retrieval. This dynamic capability resolves the contradiction by allowing the system to switch between the two opposing states rather than being stuck in one position.
Solution Approach 2:
The patent segments the downhole tool into a housing and a separable extendable component. This segmentation allows the extendable component to be independently operated - it can be extended from the housing to contact the wellbore wall for measurements, then retracted back into the housing for retrieval. The segmentation enables the component to function independently and be easily retrieved without moving the entire tool assembly.
2Loss of information
If the mudcake layer is disturbed during drilling operations, then formation evaluation data can be obtained, but the downhole tool becomes stuck to the wellbore wall
Solution Approach 1:
The dynamic extendable component allows the system to obtain formation evaluation data by extending to disturb the mudcake layer, then reliably retract to avoid getting stuck. The ability to dynamically change position prevents the tool from becoming permanently stuck after disturbing the mudcake layer.
Solution Approach 2:
The extendable component is extracted from the housing to contact the wellbore wall and disturb the mudcake layer for formation evaluation. After data collection, the component is extracted back into the housing, separating the measurement function from the tool body and enabling reliable retrieval without compromising tool integrity.
3Reliability
If the extendable component maintains full surface area contact with the wellbore wall, then sealing capability is improved, but disengagement force required increases significantly
Solution Approach 1:
The extendable component dynamically adjusts its contact state with the wellbore wall. It can maintain full surface area contact when sealing is needed, then retract to reduce contact area for easy disengagement. This dynamic transition allows the system to achieve both good sealing capability and low disengagement force at different operational stages.
Solution Approach 2:
The component is preliminarily extended to establish sealing contact with the wellbore wall before formation measurement operations begin. This preliminary action ensures proper sealing is in place before disturbing the mudcake layer or conducting measurements, preventing differential pressure sticking from the outset.
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
This method effectively reduces the holding force of the pressure differential, enabling reliable disengagement and retraction of the tool from the wellbore wall, reducing the risk of damage and operational downtime.
Implementation Method 1
The driven element is flexibly coupled to the drive element
Implementation Method 2
downhole tools used for formation evaluation in oil and gas wells often become stuck to the wellbore wall due to differential pressure
Data Source
AI summary
An extendable component for use in a downhole tool for traversing subsurface formations includes a drive element that defines an axis and has a distal end, and an abutment that is spaced radially from a distal end of the drive element. A driven element defines a driven element axis, is flexibly coupled to the drive element, and includes a proximal end disposed adjacent to the drive element and a distal end. A tilt arm is coupled to the driven element, is disposed at an angle with respect to the driven element axis, and is configured to engage the abutment. The driven element is moveable between a normal position and a tilted position. A contact head is coupled to the driven element distal end and is adapted to engage the wellbore wall.