Low-Clearance Centralizer Collar Design
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Solution Overview
Problem
Existing centralizers with movable collars require complex mechanisms and multiple components, leading to increased manufacturing costs and radial thickness, limiting their use in tight boreholes and making them expensive.
Innovation Solution
A low-clearance centralizer design formed from a single tube, using laser cutting or water jets to create interlocking extendable collars and bow-springs that can collapse to pass through tight restrictions, maintaining radial thinness and reducing assembly complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If movable collars are used to allow bow springs to flex and collapse, then the centralizer can pass through borehole obstructions, but the radial thickness increases and manufacturing complexity increases
Solution Approach 1:
The patent merges the stop collar and moving collar into a single integrated collar structure. The bow springs are directly secured to the collar body without requiring separate moving collar components. This integration eliminates the complex interlocking mechanisms while maintaining the ability of bow springs to flex and collapse when encountering borehole obstructions, thus reducing device complexity while preserving adaptability.
Solution Approach 2:
The patent extracts the unnecessary moving collar component from the traditional centralizer design. By removing the separate moving collar and its associated interlocking mechanisms, the design simplifies the overall structure while retaining the essential functionality of bow spring flexure. The bow springs are directly attached to the simplified collar, eliminating mechanical complexity.
2Adaptability or versatility
If multiple components are used to form movable collars, then the centralizer can accommodate bow spring flexure, but manufacturing cost increases and assembly complexity increases
Solution Approach 1:
The patent combines multiple separate components (stop collar, moving collar, and bow spring mounting structures) into a single integrated collar design. This reduces the number of parts that need to be manufactured and assembled, thereby lowering manufacturing costs and simplifying assembly procedures while still providing the necessary flexibility for bow spring operation.
Solution Approach 2:
The collar is designed with integrated segmentation features that allow different functional zones within a single component. The collar includes directly integrated bow spring securing structures and positioning features that eliminate the need for separate moving collar components, reducing manufacturing complexity and cost.
3Ease of operation
If axially overlapping structures are used in collars, then the collars can slidably interface to allow movement, but the radial thickness of the centralizer increases
Solution Approach 1:
The patent merges the sliding interface functionality directly into the collar body structure. The collar includes integrated grooves and protrusions that enable bow spring attachment and limited movement without requiring axially overlapping collar sections. This eliminates the need for additional radial thickness while maintaining operational flexibility.
4Ease of manufacture
If a simple stationary collar design is used, then manufacturing cost is reduced, but the centralizer cannot accommodate bow spring flexure during installation
Solution Approach 1:
The patent incorporates dynamic features directly into a simplified collar structure. The collar includes integrated flexure accommodation zones and bow spring securing structures that allow the bow springs to flex and collapse when needed, while maintaining an overall simple and manufacturable collar design. This provides adaptability without requiring complex movable collar mechanisms.
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 allows for efficient passage through tight borehole restrictions while maintaining stand-off and reducing manufacturing costs, offering a cost-effective and radially thinner solution for centralizing casing strings.
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
A low-clearance centralizer design formed from a single tube, using laser cutting or water jets to create interlocking extendable collars and bow-springs
Implementation Method 3
A low-clearance centralizer design formed from a single tube, using laser cutting or water jets to create interlocking extendable collars and bow-springs
Data Source
AI summary
A centralizer assembly includes a centralizer configured to centralize a tubular in a wellbore. The centralizer includes a first end collar, a second end collar, and ribs extending between the first and second end collars. The assembly also includes a first stop collar disposed adjacent the first end collar and including an anchor. The anchor defines a generally rectangular anchor window extending therethrough. The anchor is configured to bear on an anchoring material secured to the tubular and received through the anchor window. The anchor material includes a thermal spray applied to the tubular. The first end collar is prevented from rotation with respect to the first stop collar.