Drill String Centralizer with Eccentric Blade and Alignment Profile

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Solution Overview

Problem

Existing downhole drilling systems face challenges in efficiently centralizing the drill string within boreholes, particularly when the borehole is only slightly larger than the drill string, leading to reduced clearance and potential drilling inefficiencies.

Innovation Solution

A centralizer assembly with a single blade and alignment profile is used to securely position and align the centralizer relative to the drill string, reducing the overall circumference of the drill string and allowing precise alignment, which is retained by a threaded lower sub and mating profiles, enabling improved clearance and drilling performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If a centralizer with multiple blades is used to centralize the drill string, then the drill string is well-centered in the borehole, but the circumference of the drill string increases reducing clearance in slightly larger boreholes

Engineering Contradiction:

Improvecentralization stabilityVSAvoiddrill string circumference

Core Design Contradiction:

Stability of the object's compositionVSVolume of moving object

Solution Approach 1:

The centralizer is divided into multiple individual blades (typically 3 or more) that are attached to the drill string at different angular positions. Each blade independently contacts the borehole wall to provide centralizing force, achieving stable centering while keeping each blade thin and compact to minimize overall circumference increase

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The centralizer blades extend radially outward from the drill string in the radial dimension rather than increasing length in the axial dimension. This allows the drill string to be centered effectively without significantly increasing the overall circumference, as the blades are thin and positioned perpendicular to the drill string axis

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Volume of moving object

If the drill string circumference is reduced to provide clearance in slightly larger boreholes, then clearance is improved, but the centralizer may not effectively centralize the drill string

Engineering Contradiction:

Improvedrill string circumferenceVSAvoidcentralization stability

Core Design Contradiction:

Volume of moving objectVSStability of the object's composition

Solution Approach 1:

The centralizer blades are designed with varying local properties: they have sufficient radial thickness and width at the contact surfaces to provide effective centralizing force against the borehole wall, while being minimal in other dimensions. The blades are positioned at specific locations along the drill string where centralizing force is most needed

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The centralizer blades are positioned asymmetrically around the drill string circumference rather than being uniformly distributed, allowing optimization of centralizing force distribution for specific borehole conditions while minimizing overall material usage and circumference increase

Inventive Principle:

Principle #4Asymmetry

3Manufacturing precision

If an alignment profile is added to retain centralizer alignment, then alignment precision is improved, but device complexity increases

Engineering Contradiction:

Improvecentralizer alignment precisionVSAvoidcentralizer structure complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The alignment profile is integrated directly into the centralizer blade structure and its mounting attachment, rather than being a separate component. The alignment features are formed as part of the blade geometry itself, achieving precise angular positioning without adding separate alignment devices or increasing overall structural complexity

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The centralizer blade structure serves multiple functions simultaneously: it provides the centralizing force through radial extension, maintains angular alignment through integrated alignment profiles, and attaches to the drill string through the same mounting structure. This multi-functionality reduces the need for separate components and simplifies the overall device

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS12180788B2Drill string with centralizer

Publication Date: 2024.12.31 HALLIBURTON ENERGY SERVICES INC

AI summary

A drill string for drilling a borehole. The drill string may include a downhole motor operable to rotate the drill string and a centralizer assembly. The centralizer assembly may include an outer housing, a lower sub threadably engaged with the outer housing, and a centralizer. The centralizer may include a single eccentric blade, an internal shoulder positioned between the outer housing and the lower sub, and an alignment profile to align the centralizer in an azimuthal position relative to the drill string. The centralizer may be retainable in the aligned azimuthal position by the alignment profile and the internal shoulder being engaged by the outer housing and the lower sub.