Downhole Swelling Foam Packer Sealing with Bentonite Clay

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Solution Overview

Problem

Existing swelling packers downhole face issues with extrusion and limited contact pressure, leading to leakage due to open passages in the foam structure, which are not effectively sealed even after swelling, especially under varying differential pressures.

Innovation Solution

Incorporating a swelling material like bentonite clay within the open cell foam passages that hardens and blocks or seals these passages upon exposure to well fluids, transforming the foam from an open to a closed cell structure for enhanced sealing capabilities.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stress or pressure

If swelling material is used to increase sealing contact pressure, then sealing capability is improved, but extrusion of the sealing element occurs in longitudinal direction

Engineering Contradiction:

Improvecontact pressureVSAvoidextrusion

Core Design Contradiction:

Stress or pressureVSShape

Solution Approach 1:

The foam is pre-compressed to a compact configuration before downhole insertion, allowing it to fit within the packer housing. Upon activation, the foam automatically expands to its larger sealed configuration, applying radial contact pressure to seal the annulus without requiring manual intervention or additional equipment.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The foam undergoes a parameter change from a compressed state with low volume and pressure to an expanded state with larger volume and high radial contact pressure. This parameter transformation allows the same material to serve both as a space-efficient insert and as a high-pressure sealing element.

Inventive Principle:

Principle #35Parameter changes

2Strength

If open cell foam structure is used for swelling, then initial compressibility is improved, but passages remain open after swelling leading to leakage

Engineering Contradiction:

ImprovecompressibilityVSAvoidsealing integrity

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The foam undergoes a phase transition from an open-cell structure that allows fluid penetration and swelling to a closed-cell structure where the cells are sealed. This phase change is triggered by exposure to well fluids or chemical agents, transforming the foam's internal architecture to prevent leakage while maintaining the sealing function.

Inventive Principle:

Principle #36Phase transitions

3Ease of operation

If swelling element is constrained during run-in, then ease of insertion is improved, but swelling capability is limited until activation

Engineering Contradiction:

ImproveinsertionVSAvoidsealing performance

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The constraint mechanism is designed to be temporary and removable. Once the foam is in position, the constraint is released or removed, allowing the foam to expand freely and achieve its full sealing potential. This separation of the constrained transport state from the unconstrained sealing state resolves the contradiction.

Inventive Principle:

Principle #2Taking out (Extraction)

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 hardened particles within the foam passages create a more robust and impermeable seal, capable of retaining fluids and maintaining a seal under increased pressure conditions, thereby enhancing the sealing performance and durability of the packer.

Implementation Method 1

Exposure to well or other fluids occurs downhole as the initial restraint on the element is overcome. The element takes on well fluids as it resumes its relaxed position or swells.

Methodology Applied

Scientific EffectAbsorption: Absorption (physical)

Implementation Method 2

The material in the passages, when exposed to well fluids, itself grows in size and can get harder. It blocks or seals the passages in the foam

Methodology Applied

Scientific EffectSwelling: Hydrogel

Implementation Method 3

The material in the passages, when exposed to well fluids, itself grows in size and can get harder

Methodology Applied

Scientific EffectHardening:

Data Source

PatentUS7552767B2Closeable open cell foam for downhole use

Publication Date: 2009.06.30 BAKER HUGHES CO

AI summary

A downhole packer or sealing device uses a swelling sealing element that is initially held in a compressed state. Exposure to well or other fluids occurs downhole as the initial restraint on the element is overcome. The element takes on well fluids as it resumes its relaxed position or swells. The element is preferably an open cell material such as foam and has another material in its passages. The material in the passages, when exposed to well fluids, itself grows in size and can get harder. It blocks or seals the passages in the foam so that the swollen foam becomes more like a closed cell material and can retain a seal against a greater range of operating conditions than had its passages remained open or unobstructed with another material.