Resilient Disc Centralizer for Downhole Tool Alignment

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Solution Overview

Problem

Existing downhole tools face challenges in maintaining axial alignment and centralization within pipe or tubing bores, particularly due to limitations in radial cutting capacity of shaped charge cutters and difficulties in fabricating and assembling complex centralizing devices, which can lead to incomplete cuts and increased material usage.

Innovation Solution

The use of two or more thin, resilient metal discs or spring steel wires attached to a tool housing end, secured by a single pin fastener or interference fit, to provide centralization and prevent rotation, allowing for efficient engagement with the pipe or tubing wall and reducing material waste in fabrication.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If elaborate centralizer designs are used, then centralization performance is improved, but fabrication and assembly difficulties increase

Engineering Contradiction:

Improvecentralization performanceVSAvoidfabrication and assembly

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The centralizer is divided into multiple individual blades instead of using a single complex structure. Each blade is a separate, simple component that can be manufactured independently and then assembled by attaching them to the tool housing, thereby simplifying both fabrication and assembly processes while maintaining centralization effectiveness.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The centralizer uses simple, inexpensive blade components that can be easily manufactured and replaced if needed. These blades are designed as basic structural elements rather than complex mechanisms, reducing fabrication costs and complexity while providing sufficient functional performance for the application.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

2Reliability

If multiple centering blades are formed from a single sheet of spring steel, then centralization is achieved, but material usage increases

Engineering Contradiction:

ImprovecentralizationVSAvoidmaterial usage

Core Design Contradiction:

ReliabilityVSLoss of substance

Solution Approach 1:

Instead of forming multiple blades from a single large sheet of spring steel, the design uses multiple separate, smaller blade components. This segmentation allows for more efficient material utilization, reducing waste while achieving the same centralization function through multiple smaller elements rather than one large complex piece.

Inventive Principle:

Principle #1Segmentation

3Ease of operation

If shaped charge cutter alignment is eccentric with the pipe axis, then tool operation is simplified, but cutting completeness deteriorates

Engineering Contradiction:

Improvetool operationVSAvoidcutting completeness

Core Design Contradiction:

Ease of operationVSManufacturing precision

Solution Approach 1:

The centralizer uses resilient blades that can dynamically adjust their position and orientation in response to variations in pipe geometry and tool alignment. This dynamic adaptation allows the blades to maintain effective centralization even when the tool is not perfectly aligned with the pipe axis, ensuring complete cuts while simplifying operational requirements.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The resilient blade design provides a cushioning effect that compensates for potential misalignment issues before they result in incomplete cuts. The blades can flex and adjust to accommodate alignment variations, preventing the harmful effect of eccentric positioning from compromising cutting completeness.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

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 solution enables cost-effective and easy attachment of centralizers, improving the radial cutting capacity and maintaining tool alignment, thereby enhancing the accuracy and efficiency of downhole operations while minimizing material usage and fabrication complexities.

Implementation Method 1

two or more thin, resilient metal discs or spring steel wires attached to a tool housing end

Methodology Applied

Scientific EffectElasticity: Elasticity

Implementation Method 2

the opposite flanks of the V-groove expansively explode against each other to produce a rapidly expanding jet of metal material

Methodology Applied

Scientific EffectDetonation: Detonation

Implementation Method 3

sever the pipe wall by hydrodynamically splashing the material out of the way

Methodology Applied

Scientific EffectHydrodynamic effect:

Implementation Method 4

secured by an interference fit or other securing methods. The interference fit may be obtained by swaging or by thermal shrinkage

Methodology Applied

Scientific EffectThermal shrinkage: Thermal Contraction

Data Source

PatentUS10161197B2Well tool centralizer systems and methods

Publication Date: 2018.12.25 W T BELL INT INC

AI summary

An apparatus for, and method of, centering downhole well tools within the wellbore of a pipe comprises at least a pair of discs secured, respectively, to the distal end of a tool in a plane normal to a longitudinal tool axis, with an arc of each disc extended past the outer perimeter of the tool to at least an internal perimeter of an applied pipe bore and flexing to centralize the tool. In alternative embodiments, the discs are replaced by blades that are secured by a plurality of attachment points and fasteners, or by spring steel wires that are secured in radial apertures through an end boss by interference fit, soldering, swaging, or gluing.