Dissolvable Retaining Members for Downhole Centralizer Deployment

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Solution Overview

Problem

Existing centralizers face challenges in navigating through narrow borehole diameters and restrictions, as pushing them can increase friction and require more load, limiting the number that can be run and affecting cement uniformity and centralization efficiency.

Innovation Solution

A centralizer design featuring a first and second end collar with elongate bow-spring members, temporarily retained in a flat position by dissolvable retention members, which dissolve in downhole fluids to allow the bow-spring members to expand radially, reducing drag and enabling more centralizers to be run while maintaining effective centralization.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If centralizers are pushed through narrow borehole diameters, then they can be deployed in restricted areas, but friction increases and more load is required, limiting the number of centralizers that can be run

Engineering Contradiction:

Improveability to navigate narrow borehole diametersVSAvoidfriction and drag

Core Design Contradiction:

Adaptability or versatilityVSObject-generated harmful factors

Solution Approach 1:

The centralizer employs movable end collars that can slide relative to each other along the tubular, allowing the centralizer to dynamically compress and expand. This dynamic capability enables the centralizer to adapt to varying borehole diameters and pass through narrow restrictions with reduced friction, while maintaining effective centralization in wider sections.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The centralizer's outer diameter parameter is made variable through the sliding end collar mechanism. In restricted areas, the end collars slide to reduce the overall diameter, allowing passage through narrow boreholes. In wider sections, the end collars can be positioned to maximize the centralizing effect, thereby changing the effective parameter to suit different downhole conditions.

Inventive Principle:

Principle #35Parameter changes

2Manufacturing precision

If more centralizers are run to improve centralization, then cement uniformity improves, but the load and friction increase, limiting how many can be deployed

Engineering Contradiction:

Improvecement uniformityVSAvoidfriction and drag

Core Design Contradiction:

Manufacturing precisionVSObject-generated harmful factors

Solution Approach 1:

The dynamic sliding mechanism allows each centralizer to optimize its profile for the specific borehole section it occupies. This reduces the friction and load each individual centralizer experiences, thereby reducing the total load and friction for a string of multiple centralizers, enabling deployment of more centralizers to achieve better cement uniformity.

Inventive Principle:

Principle #15Dynamics

3Stability of the object's composition

If end collars are fixed to prevent movement, then the centralizer maintains its shape, but it cannot be compressed to pass through narrow regions

Engineering Contradiction:

Improvecentralizer shape stabilityVSAvoidability to pass through narrow restrictions

Core Design Contradiction:

Stability of the object's compositionVSAdaptability or versatility

Solution Approach 1:

The end collars are designed with sliding capability along the tubular while maintaining rotational stability and radial positioning. This allows the centralizer to dynamically adjust its axial configuration for passing through restrictions while maintaining the structural integrity and shape stability needed for effective centralization in the deployed position.

Inventive Principle:

Principle #15Dynamics

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 design allows for improved centralization with reduced drag, enabling more centralizers to be deployed efficiently, reducing run times and costs, and accommodating various borehole geometries by minimizing contact with the wellbore wall during deployment.

Implementation Method 1

a dissolvable retention member coupled to the second end collar. The dissolvable retention member is configured to maintain a position of the second end collar relative to the first end collar until the dissolvable retention member at least partially dissolves in a downhole fluid

Methodology Applied

Scientific EffectDissolution:

Implementation Method 2

multiple elongate members extending between and connected to the first and second end collars... When the dissolvable retention member at least partially dissolves, the second end collar is configured to move with respect to the first end collar, and the plurality of elongate members expand radially outwards

Methodology Applied

Scientific EffectElasticity: Elasticity

Data Source

PatentUS11125024B2Centralizer with dissolvable retaining members

Publication Date: 2021.09.21 INNOVEX DOWNHOLE SOLUTIONS LLC

AI summary

A downhole tool may include a first end collar configured to be positioned at least partially around a tubular, a second end collar configured to be positioned at least partially around the tubular, a plurality of elongate members extending between and connected to the first and second end collars, and a dissolvable retention member coupled to the second end collar. The dissolvable retention member is configured to maintain a position of the second end collar relative to the first end collar until the dissolvable retention member at least partially dissolves in a downhole fluid. When the dissolvable retention member at least partially dissolves, the second end collar is configured to move with respect to the first end collar, and the plurality of elongate members expand radially outwards.