Variable Thickness Sleeve for High Collapse Loads

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Solution Overview

Problem

Downhole tools face challenges in withstanding high pressure differentials in wellbores, as existing sleeves with constant thickness may collapse, potentially damaging electronic devices and sensors due to inadequate protection, and there is a space constraint for thicker sleeves to ensure adequate protection.

Innovation Solution

A downhole tool design featuring a mandrel with pockets for electronic devices and a sleeve with conic sections that have a smaller cross-sectional thickness than support sections, distributing stress through a parabolic arch shape to withstand higher pressure differentials while maintaining a smaller profile.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the cross-sectional thickness of the sleeve is increased to withstand high pressure differentials, then the protection capability against collapse loads is improved, but the available space in the wellbore is reduced

Engineering Contradiction:
Improveprotection capability against collapse loadsVSAvoidavailable space in wellbore
Core Design Contradiction:
StrengthVSVolume of moving object

Solution Approach 1:

The sleeve transitions from a uniform thickness design to a variable thickness design where thicker support sections are strategically positioned at locations requiring maximum strength (between pockets and at ends) while thinner conic sections are placed where less structural support is needed. This local differentiation of thickness allows the sleeve to maintain adequate protection capability while reducing the overall volume and external dimensions of the tool assembly.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The sleeve is segmented into distinct functional zones: conic sections with smaller thickness and support sections with larger thickness. This segmentation allows each portion to be optimized for its specific function - the conic sections provide fluid flow paths and basic protection, while the support sections provide structural reinforcement against collapse loads. The segmented approach enables the sleeve to withstand high pressure differentials without requiring uniform thickening throughout the entire circumference.

Inventive Principle:
Principle #1Segmentation

2Reliability

If the cross-sectional thickness of the sleeve is increased to protect devices from pressure differentials, then the reliability of device protection is improved, but the device complexity increases

Engineering Contradiction:
Improvedevice protection from pressure differentialsVSAvoidsleeve structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The conic sections incorporate curved surfaces (parabolic or conical geometry) that naturally distribute applied pressure loads along the curved path, reducing stress concentrations. This curvature provides inherent structural efficiency, allowing the thinner conic sections to contribute to pressure resistance without adding complex reinforcement features. The curved geometry is formed through standard manufacturing processes, avoiding the need for complex assembly steps or multiple components.

Inventive Principle:
Principle #14Spheroidality (Curvature)

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 conic section design allows the downhole tool to withstand higher pressure differentials without increasing the sleeve's cross-sectional thickness, effectively protecting devices and preventing fluid ingress, even in deep wellbores where space is limited.

Implementation Method 1

The conic section may form an arch between the second and third portions of the sleeve... providing an arch with the inner surface of each of the first plurality of sections between two adjacent sections of the second plurality of sections

Methodology Applied
Scientific EffectArch shape stress distribution: Arch

Data Source

PatentEP3714133B1Method for withstanding high collapse loads from differential pressure in a limited cross-section
Publication Date: 2023.02.15 BAKER HUGHES CO
  • EP3714133B1 patent drawingFigure 1~2
  • EP3714133B1 patent drawingFigure 3
  • EP3714133B1 patent drawingFigure 4

AI summary

A downhole tool and method of using the tool that includes a mandrel having at least one pocket formed in an exterior surface of the mandrel. The tool includes a sleeve positioned on the exterior of the mandrel to cover the pocket. A first portion of the sleeve is a conic section and is positioned adjacent to the pocket. The conic section of the sleeve may have a smaller cross-sectional thickness than a supporting portion of the sleeve. A curvature of the inner surface of conic section may differ from the curvature of the inner surface of the supporting section of the sleeve. The inner surface of the conic section may be an arch, a parabolic shape, or the like. The mandrel may include a plurality of pockets and the sleeve may include a plurality of corresponding conic sections separated by supporting sections that engage the exterior of the mandrel.