Compressible Particles for Trapped Annulus Pressure Mitigation

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Solution Overview

Problem

In hydrocarbon recovery operations, trapped annuli in wellbores experience pressure increases due to production fluids, which can exceed the pressure ratings of inner casing strings, leading to potential pipe collapse or well failure, as there is no effective means to mitigate pressure within these confined volumes.

Innovation Solution

A method involving the placement of a fluid mixture containing compressible particles within the wellbore, where the particles are designed to collapse and absorb increased fluid pressure, comprising an aqueous carrier fluid and particles with high compressibility and resiliency, allowing them to deform and recover volume in response to pressure changes, thereby reducing the risk of pipe collapse.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If cement is placed in the annulus to strengthen the wellbore, then wellbore strength is improved, but pressure buildup occurs in trapped annuli because cement is incompressible

Engineering Contradiction:

Improvewellbore strengthVSAvoidpressure in trapped annuli

Core Design Contradiction:

StrengthVSStress or pressure

Solution Approach 1:

The patent changes the physical parameter of the annular material from incompressible (cement) to compressible (particles with air pockets). The particles are designed with specific density, compressibility, and resiliency parameters that allow them to change volume in response to pressure changes, thereby mitigating pressure buildup while maintaining wellbore strength.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent uses composite particles consisting of a solid matrix with embedded air pockets or voids. This composite structure combines the strength-providing solid material with the compressibility-providing air spaces, creating a material that simultaneously strengthens the wellbore and absorbs pressure increases through volumetric compression.

Inventive Principle:

Principle #40Composite materials

2Stress or pressure

If the annulus is left uncemented to avoid pressure buildup, then pressure mitigation is improved, but wellbore strength and zonal isolation are reduced

Engineering Contradiction:

Improvepressure mitigation in annuliVSAvoidwellbore strength

Core Design Contradiction:

Stress or pressureVSStrength

Solution Approach 1:

The patent transforms the annular space from a rigid, strength-providing cemented structure to a flexible, compressible particle-filled structure. The particles' ability to change volume under pressure provides inherent pressure mitigation while their collective structure maintains wellbore strength and isolation capabilities.

Inventive Principle:

Principle #35Parameter changes

3Productivity

If production fluids are allowed to heat the wellbore, then production efficiency is improved, but thermal expansion causes pressure increases that may exceed casing pressure ratings

Engineering Contradiction:

Improveproduction efficiencyVSAvoidpressure from thermal expansion

Core Design Contradiction:

ProductivityVSStress or pressure

Solution Approach 1:

The patent utilizes thermal expansion principles by incorporating compressible particles that can increase in volume in response to thermal effects. As production fluids heat the wellbore, the particles absorb the thermal expansion of fluids through their own volumetric expansion and compression, preventing dangerous pressure buildup while allowing efficient production.

Inventive Principle:

Principle #37Thermal expansion

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 mitigate pressure increases within trapped annuli, providing additional volume for fluid expansion and reducing the likelihood of pipe collapse, thus ensuring the integrity of wellbore tubulars during production operations.

Implementation Method 1

Each of the compressible particles is fabricated to collapse in response to fluid pressure within a confined volume

Methodology Applied

Scientific EffectCompressibility: Compression

Implementation Method 2

resiliency to elastically recover at least 50% of the at least 10% volumetric deformation in response to reversal of the change in fluid pressure

Methodology Applied

Scientific EffectElastic recovery: Elasticity

Implementation Method 3

Each of the compressible particles has a density that is less than a specific gravity of the carrier medium, facilitating buoyancy

Methodology Applied

Scientific EffectBuoyancy: Archimedes' Principle (Buoyancy)

Data Source

PatentUS11359129B2Method of placing a fluid mixture containing compressible particles into a wellbore

Publication Date: 2022.06.14 EXXONMOBIL UPSTREAM RESEARCH COMPANY(US)

AI summary

A method of placing compressible particles within a wellbore. The method first comprises accessing a wellbore. The wellbore has a first string of casing and a second string of casing, wherein the first string of casing surrounds an upper portion of the second string of casing, forming a trapped annulus. The method further includes pumping a fluid mixture down the second string of casing and back up the annulus. The fluid mixture comprises an aqueous carrier fluid having a plurality of compressible particles dispersed therein. Each of the compressible particles is fabricated to collapse in response to fluid pressure within the trapped annulus. The method additionally includes pumping cement into at least a lower portion of the annulus behind the fluid mixture, forming a column of cement, and thereby placing the fluid mixture in the annulus above the column of cement.