Wear-Resistant Annular Seal Assembly for Straddle Packer

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Solution Overview

Problem

Traditional straddle packers with elastomeric packer elements face wear and material fatigue issues in perforated well casings, leading to frequent replacements and inefficient production stimulation in long lateral well bores, as they are vulnerable to casing burrs and high-pressure stresses.

Innovation Solution

A wear-resistant annular seal assembly with interlocking segments supported by active and reactive segment cones, connected to seal sleeves and mandrels, which radially expand from a run-in to a seal-set condition under axial force, incorporating a reactive coil spring for constant urging and leveling springs for alignment, allowing for extended service cycles and easier movement within perforated casings.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If elastomeric packer elements are used to seal against well casing, then fluid pressure isolation is achieved, but the packer elements are vulnerable to wear and damage from casing burrs and formation intrusions

Engineering Contradiction:

Improvefluid pressure isolationVSAvoidwear and damage from casing burrs

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The invention changes the material parameter from elastomeric to metal, transforming the packer element properties to resist wear and damage while maintaining sealing capability through controlled deformation

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention uses composite construction with metal packer elements incorporating elastomeric sealing surfaces, combining the wear resistance of metal with the sealing effectiveness of elastomers

Inventive Principle:

Principle #40Composite materials

2Reliability

If elastomeric packer elements are expanded to pack-off effectively, then fluid containment is improved, but the elements are subject to material fatigue from extreme pressure stresses

Engineering Contradiction:

Improvefluid containmentVSAvoidservice life under pressure

Core Design Contradiction:

ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The invention changes the material parameter from elastomeric to metal, which has superior fatigue resistance and can withstand extreme pressure stresses without material fatigue, thereby extending service life while maintaining fluid containment

Inventive Principle:

Principle #35Parameter changes

3Reliability

If traditional straddle packers are used in long lateral well bores, then fluid isolation is provided, but frequent packer element replacements are required which are time consuming

Engineering Contradiction:

Improvefluid isolationVSAvoidtime for packer element replacements

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The invention changes the material parameter from elastomeric to metal, creating wear-resistant packer elements that extend service life and reduce the frequency of replacements, thereby reducing time loss in long lateral well bores

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention makes the packer elements resettable through controlled deformation and elastic recovery, allowing them to be reused multiple times without replacement, which significantly reduces maintenance time in long lateral well bores

Inventive Principle:

Principle #15Dynamics

4Productivity

If fixed packer is set at heel of well bore for stimulation, then stimulation can proceed, but control of fluid and proppant placement within producing formation is lost

Engineering Contradiction:

Improvestimulation efficiencyVSAvoidcontrol of fluid placement

Core Design Contradiction:

ProductivityVSEase of operation

Solution Approach 1:

The invention uses multiple straddle packers spaced at intervals along the well bore, creating multiple isolated sections that enable sequential stimulation and precise control of fluid and proppant placement in different producing formation zones

Inventive Principle:

Principle #1Segmentation

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 solution provides a durable and reliable fluid pressure isolation system that reduces wear and fatigue, enabling extended service life and efficient production stimulation with improved control over fluid and proppant placement in well bores, facilitating single downhole runs and reducing the need for frequent packer element replacements.

Implementation Method 1

a reactive coil spring that constantly urges the reactive seal sleeve to urge the interlocking seal segments to a run-in condition

Methodology Applied

Scientific EffectElastic force: Spring

Implementation Method 2

the interlocking seal segments being adapted to radially expand from a run-in condition to a seal-set condition when an axial force acting on the active seal sleeve urges the active segment cone towards the reactive segment cone

Methodology Applied

Scientific EffectRadial expansion under axial compression: Deformation

Data Source

PatentUS11473393B2Wear-resistant annular seal assembly and straddle packer incorporating same

Publication Date: 2022.10.18 EXACTA FRAC ENERGY SERVICES INC

AI summary

A wear-resistant annular seal assembly has a plurality of interlocking one-piece seal segments interleaved with a plurality of two-piece seal segments. The seal segments are made using wear-resistant rigid material such as stainless steel. In one embodiment the seal segments are coated with a fluoropolymer. A straddle packer includes a first and second spaced apart ones of the wear-resistant seal assemblies and a linear force generator for urging the first and second seal assemblies to a seal-set condition.