POSS Epoxy Resin Seals Wellbore Annulus

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Solution Overview

Problem

Cement sheaths in wellbores are prone to micro-cracks due to temperature and pressure cycling, leading to fluid migration through the casing-casing annulus, causing pressure buildup and damage to well structures, especially in hydrocarbon gas wells.

Innovation Solution

An epoxy resin system comprising a polyhedral oligomeric silsesquioxane (POSS) epoxy resin and a curing agent is introduced into the wellbore to form a cured barrier that prevents fluid leaks into the casing-casing annulus, effectively sealing defects and withstanding significant differential pressure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If wellbore cement is used for primary sealing, then the annulus is sealed to prevent fluid migration, but micro-cracks form due to temperature and pressure cycling, leading to fluid leaks and pressure buildup

Engineering Contradiction:

Improvesealing effectivenessVSAvoidcement sheath integrity

Core Design Contradiction:

ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent introduces an epoxy resin system with specific chemical composition parameters (epoxy resin to curing agent ratio, viscosity range, molecular weight) that differ from conventional cement. This parameter change enables the sealing material to maintain flexibility and adhesion under temperature and pressure cycling, preventing micro-crack formation while maintaining sealing effectiveness.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent uses a composite epoxy resin system comprising epoxy resin, curing agent, and optional additives. This composite material combines the advantages of chemical bonding, flexibility, and pressure resistance, creating a sealing material that maintains integrity under thermal and pressure stress while preventing fluid migration through the annulus.

Inventive Principle:

Principle #40Composite materials

2Ease of manufacture

If conventional cement is used for sealing, then initial sealing is achieved, but the material cannot withstand significant differential pressure, causing fluid migration through defects

Engineering Contradiction:

Improvesealing process simplicityVSAvoidpressure resistance

Core Design Contradiction:

Ease of manufactureVSStrength

Solution Approach 1:

The patent specifies particular parameter ranges for the epoxy resin system including viscosity (10-10,000 cP), molecular weight (500-50,000 g/mol), and epoxy equivalent weight (100-500 g/eq). These parameter changes enable the material to be pumped through the wellbore easily while maintaining the strength to withstand differential pressures exceeding 10,000 psi, solving both ease of application and pressure resistance requirements.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent describes a method that replicates the successful application principles of conventional cementing (simple injection through the annulus) while using improved epoxy resin material. The process copies the ease of manufacture and application of cement but achieves superior pressure resistance through the enhanced material properties of the epoxy resin system.

Inventive Principle:

Principle #26Copying

3Reliability

If the epoxy resin system is introduced to seal defects, then an impermeable barrier is formed to prevent fluid leaks, but the system must be maintained under significant differential pressure to remain effective

Engineering Contradiction:

Improvezonal isolation effectivenessVSAvoiddifferential pressure withstand

Core Design Contradiction:

ReliabilityVSStress or pressure

Solution Approach 1:

The patent employs a composite epoxy resin system with carefully selected components and ratios that provide both impermeability and pressure resistance. The combination of epoxy resin, curing agent, and optional additives creates a material structure that forms effective zonal isolation while withstanding differential pressures, resolving the contradiction between sealing effectiveness and pressure withstand capability.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent applies the epoxy resin system specifically to the defective regions and annulus requiring sealing, creating localized zones of enhanced integrity. The material's ability to adhere to casing and formation surfaces creates a locally optimized barrier that prevents fluid migration at critical points while maintaining overall system reliability under pressure.

Inventive Principle:

Principle #3Local quality

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 cured epoxy resin system provides effective zonal isolation and repairs leaks, maintaining structural integrity by forming an impermeable barrier that resists fluid migration and pressure differentials, thereby preventing damage to wellbore structures.

Implementation Method 1

maintaining the epoxy resin system in the wellbore such that a cured epoxy resin system product forms in the wellbore defect

Methodology Applied

Scientific EffectCuring:

Data Source

PatentUS11618842B2Nanosized dendrimeric epoxy resin to prevent casing-casing annulus pressure issues

Publication Date: 2023.04.04 SAUDI ARABIAN OIL CO

AI summary

A method includes introducing an epoxy resin system to a wellbore defect in a wellbore. The epoxy resin system comprises a polyhedral oligomeric silsesquioxane (POSS) epoxy resin with at least one reactive group and a curing agent. The method includes maintaining the epoxy resin system in the wellbore such that a cured epoxy resin system product forms in the wellbore defect.