Low-Clearance Centralizer Collar Design for Tight Boreholes
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing centralizers with extendable collars require axially overlapping structures, increasing radial thickness and manufacturing costs, making them bulky and expensive to produce and assemble.
Innovation Solution
A low-clearance centralizer design featuring stop collars and moving collars formed from a single tube, with bow springs that deploy radially outwardly to provide stand-off and collapse for passage through tight borehole restrictions, using a laser or water jet to cut the tube into interlocking pieces for efficient manufacturing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If axially overlapping structures are used in extendable collars, then the centralizer can provide stand-off and centering function, but the radial thickness increases and manufacturing complexity increases
Solution Approach 1:
The patent combines the stop collar and moving collar into a single integrated collar structure, eliminating the need for axially overlapping components. This merging reduces the overall radial thickness while maintaining the extendable functionality needed for stand-off, directly resolving the contradiction between reliability and device complexity.
Solution Approach 2:
The collar is segmented into functional zones within a single continuous structure, allowing it to exhibit both stop and moving collar characteristics without requiring separate overlapping components. This segmentation approach maintains the necessary mechanical functions while reducing structural complexity.
2Reliability
If axially overlapping structures are used in extendable collars, then the centralizer can provide stand-off function, but the manufacturing cost increases
Solution Approach 1:
By merging the stop collar and moving collar into one integrated component, the patent reduces the number of parts that need to be manufactured, assembled, and inventoried. This single-component design simplifies manufacturing processes and reduces assembly operations, directly addressing the manufacturing cost issue while preserving the stand-off function.
Solution Approach 2:
The integrated collar serves multiple functions (both stop and moving collar functions) within a single structure, eliminating the need for separate specialized components. This multi-functionality reduces the overall bill of materials and manufacturing complexity, thereby reducing production costs.
3Ease of operation
If traditional extendable collars are used, then the centralizer can deploy to center casing, but the radial thickness increases making it bulky
Solution Approach 1:
The integration of stop and moving collar functions into a single collar reduces the overall radial envelope of the centralizer. By eliminating the axial overlap between separate collars, the design achieves a more compact radial profile while maintaining full centering capability.
Solution Approach 2:
The collar design incorporates flexible elements that allow the structure to achieve its functional extended state during operation while maintaining a compact form factor when not in use, effectively reducing the permanent radial thickness requirement.
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 design achieves a low-clearance profile while reducing manufacturing complexity and costs, allowing the centralizer to pass through tight borehole restrictions and maintain effective stand-off without the need for overlapping structures.
Implementation Method 1
Elasticity allows the bow-springs to spring back to substantially their original shape after collapsing to pass a borehole obstruction, and to thereby maintain the desired stand-off between the casing string and the interior wall of the borehole
Implementation Method 2
using a laser or water jet to cut the tube into interlocking pieces for efficient manufacturing
Implementation Method 3
using a laser or water jet to cut the tube into interlocking pieces for efficient manufacturing
Data Source
AI summary
An apparatus for securing to a tubular includes a tubular base configured to be disposed around the tubular, the base defining a longitudinal central axis therethrough and including axial ends. The apparatus includes fingers extending from at least one of the axial ends of the base and substantially parallel to the longitudinal central axis. The fingers are separated circumferentially apart by slots, at least one of which does not extend across the base. The apparatus includes a sleeve configured to be disposed around the tubular and slid straight axially over the fingers, such that an elasticity of the sleeve provides a radially-inward gripping force on the fingers. The gripping force prevents the base, the plurality of fingers, and the sleeve from rotating relative to the tubular and from moving axially relative to the tubular. The sleeve may abut a stop wall of the base when slid onto the fingers.