Expandable Downhole Cutting Ring With Gap-Free Segment Assembly
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Solution Overview
Problem
Existing downhole apparatuses for cutting and removing material from wellbores or subterranean formations face inefficiencies and limitations in expansion and collapse mechanisms, leading to gaps, manufacturing difficulties, and reduced robustness.
Innovation Solution
A downhole apparatus comprising a plurality of wedge-shaped elements assembled to form a ring structure that can be expanded or collapsed by an axial actuation force, featuring interlocking profiles and biasing elements to ensure smooth expansion and contraction without gaps, allowing for optimal diameter adjustment and torque transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If traditional segmented packing rings with engaging ends are used, then the apparatus can be assembled from segments, but gaps occur between segments during expansion leading to reduced cutting efficiency
Solution Approach 1:
The cutting structure is divided into multiple wedge-shaped elements that can be assembled into a ring configuration. Each element includes cutting elements positioned on its outer surface, and the segments are designed with interlocking features that engage during expansion to maintain continuous cutting contact with the formation.
Solution Approach 2:
The wedge-shaped elements are configured to nest within each other during the collapsed state for transport through the wellbore, and expand outward to form a complete ring structure at the target location. The elements are received within a housing that guides their expansion and interlocking motion.
2Ease of operation
If tapered surfaces with axial movement are used to expand the radially movable member, then expansion mechanism is achieved, but the structure becomes complex with multiple movable members
Solution Approach 1:
The complex multi-member expansion mechanism is replaced by extracting the essential function into a simplified wedge-shaped element design. Each element independently converts axial compression force into radial expansion through its wedge geometry, eliminating the need for multiple interacting movable members with tapered surfaces.
Solution Approach 2:
The expansion is achieved by changing the geometric parameters of the wedge-shaped elements themselves rather than through complex mechanical linkages. The wedge angle and surface geometry are optimized to convert axial displacement into radial expansion, simplifying the overall mechanism while maintaining functionality.
3Productivity
If the apparatus is designed to expand to optimal diameter for cutting, then cutting efficiency is improved, but the apparatus becomes difficult to transport through the wellbore in collapsed state
Solution Approach 1:
The wedge-shaped elements are designed to collapse into a compact nested configuration during transport through the wellbore, significantly reducing their overall length and diameter. At the target location, the elements expand outward from this compact state to achieve the optimal cutting diameter, enabling both efficient transport and effective operation.
Solution Approach 2:
The apparatus transitions dynamically between two states: a compact collapsed state for transport through the wellbore and an expanded state for cutting operations. The wedge-shaped elements are designed to smoothly transition between these states, maintaining structural integrity while changing dimensions to meet different operational requirements.
4Reliability
If interlocking profiles are added to ensure smooth expansion without gaps, then cutting surface continuity is improved, but manufacturing complexity increases
Solution Approach 1:
The wedge-shaped elements incorporate asymmetric interlocking profiles with tongues and grooves that are optimized for their specific position in the ring sequence. The asymmetric geometry ensures proper orientation and smooth interlocking during expansion, while the profiles are designed to be manufacturable using standard machining operations.
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 efficient cutting and removal of material with a continuous cutting surface, adaptable diameter, and reduced risk of damage to wellbore components, while maintaining robustness and manufacturing feasibility.
Implementation Method 1
A downhole apparatus comprising a plurality of wedge-shaped elements assembled together to form a ring structure oriented in a plane around a longitudinal axis
Implementation Method 2
featuring interlocking profiles and biasing elements to ensure smooth expansion and contraction without gaps
Data Source
Figure 1A~1D
Figure 2A~2D
Figure 3A~3B
AI summary
The invention provides a downhole apparatus (50) and method of use. The apparatus comprises a plurality of elements (60) assembled together to form a ring structure oriented in a plane around a longitudinal axis and a drive mechanism for effecting rotation of the ring structure with respect to a wellbore or subterranean formation. The ring structure is operable to be moved between a collapsed condition and a first expanded condition by movement of the plurality of elements, and the ring structure comprises one or more surfaces or formations for cutting and/or removal of material from the wellbore or subterranean formation.