Wellbore Casing Attachment Using Compressible Packing for Annular Pressure

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Solution Overview

Problem

The buildup of pressure in non-cemented annular regions of wellbores due to thermal expansion of production fluids poses a risk of pipe collapse and well failure, necessitating a solution to absorb and mitigate this pressure effectively.

Innovation Solution

The implementation of compressible particles, such as carbonaceous materials with reversible volumetric expansion, is fixed at selected locations within the annular regions of wellbores to absorb pressure changes caused by thermal expansion of production fluids.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If compressible particles are added to the annular region, then pressure absorption capability is improved, but device complexity increases

Engineering Contradiction:

Improvepressure absorption capabilityVSAvoiddevice complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent utilizes compressible particles with porous structures that can absorb pressure changes through their compressibility. These particles are placed in the annular region between casing strings, where they expand and contract in response to pressure variations, providing pressure absorption capability without requiring complex active control systems.

Inventive Principle:

Principle #31Porous materials

Solution Approach 2:

The compressible particles act as an intermediary material between the cemented and non-cemented annular regions. They serve as a buffer that mediates pressure transmission, absorbing pressure spikes from thermal expansion while allowing gradual pressure equalization, thus protecting the casing structure.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Ease of manufacture

If the annular region is left non-cemented to save time and money, then ease of manufacture is improved, but harmful pressure buildup increases

Engineering Contradiction:

Improveease of manufactureVSAvoidpressure buildup

Core Design Contradiction:

Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The patent extracts the pressure absorption function from the cement material itself and implements it separately using compressible particles. This allows the annular region to remain non-cemented (maintaining ease of manufacture) while still providing pressure mitigation through the inserted compressible particle layer.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The compressible particles are placed in the annular region beforehand to provide cushioning against future pressure buildup. This preventive measure allows the system to withstand thermal expansion pressures without requiring complex active pressure management systems during operation.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

3Strength

If cement is used to fully cement the annular region, then structural strength is improved, but loss of time and increased cost occur

Engineering Contradiction:

Improvestructural strengthVSAvoidloss of time

Core Design Contradiction:

StrengthVSLoss of time

Solution Approach 1:

The patent applies cement only in specific locations where structural support is most needed, rather than fully cementing the entire annular region. Compressible particles are used in other areas to provide pressure absorption, creating a hybrid system that optimizes both strength and installation efficiency.

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 compressible particles effectively absorb pressure changes, reducing the risk of pipe collapse and well failure by providing a mechanism to mitigate annular pressure buildup during hydrocarbon production.

Implementation Method 1

absorb pressure changes caused by thermal expansion of production fluids

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 2

compressible particles, such as carbonaceous materials with reversible volumetric expansion

Methodology Applied

Scientific EffectCompressibility: Compression

Data Source

PatentUS12584373B2Casing attachment system for attenuating annular pressure buildup

Publication Date: 2026.03.24 EXXONMOBIL TECHNOLOGY & ENGINEERING CO

AI summary

A method of attenuating annular pressure buildup within a wellbore. The method includes running first and second strings of casing into a wellbore, wherein the first string of casing surrounds an upper portion of the second string of casing forming an annular region. The method also includes providing a packing of compressible material within the annular region. The compressible material comprises carbonaceous particles. The particles may reside within a porous sleeve or filter, or they may be packed together in a matrix using a cross-linked polymer or binder. The packing is fixed at a selected depth within the annular region, and is designed so that the compressible material absorbs pressure in response to thermal expansion of wellbore fluids during the production of hydrocarbon fluids from the wellbore. The method further includes placing a wellhead over the wellbore, thereby forming a trapped annulus in the wellbore over the annular region.