Dissolvable Casing Buoyancy System for Debris-Free Cementing

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Solution Overview

Problem

Existing casing buoyancy systems (CBSs) for subterranean wellbore operations face challenges such as generating significant debris during removal, potential damage to downhole equipment, and increased risks of failure during cementing operations due to obstruction of fluid flow and debris accumulation.

Innovation Solution

A modified casing buoyancy system comprising a cylindrical housing with inner and outer tubulars, where the outer tubular is dissolvable and includes a mechanical connector for controlled release, allowing for buoyancy assistance during casing operations and conversion to a cement plug for unrestricted wellbore access post-cementing, minimizing debris and equipment risks.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a traditional casing buoyancy system is used to reduce drag forces during casing operations, then the casing string can be lowered more easily, but significant debris is generated during removal and downhole equipment may be damaged

Engineering Contradiction:

Improveease of casing string loweringVSAvoiddebris generation and equipment damage

Core Design Contradiction:

Ease of operationVSObject-generated harmful factors

Solution Approach 1:

The buoyancy system is divided into separate modular components including a buoyancy generator, housing, and release mechanism. This segmentation allows the system to be deployed and removed as discrete units, minimizing debris generation during removal operations while maintaining the buoyant force needed for easy casing string lowering.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

A controlled release mechanism acts as an intermediary between the buoyancy system and the casing string. This intermediary component allows for controlled detachment and removal of the buoyancy system without causing damage to downhole equipment or generating excessive debris, while still providing the necessary buoyant force during the casing lowering operation.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Force

If a casing buoyancy system is deployed to float the casing string downhole, then drag forces are reduced, but fluid flow is obstructed and debris accumulates increasing failure risks during cementing operations

Engineering Contradiction:

Improvebuoyant force reducing dragVSAvoidrisk of failure during cementing operations

Core Design Contradiction:

ForceVSReliability

Solution Approach 1:

The system employs a dynamic controlled release mechanism that allows the buoyancy system to be deployed during casing operations and then controllably removed or opened during cementing operations. This dynamic transition eliminates fluid flow obstruction and debris accumulation risks while maintaining the buoyant force when needed, thereby improving reliability during critical cementing operations.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The buoyancy system is designed to be temporarily deployed and then discarded or recovered at the appropriate time. The controlled release mechanism enables the system to be discarded in a controlled manner during cementing operations, eliminating the obstruction and debris risks associated with leaving the system in place, while recovering the buoyant force benefit during the earlier casing lowering phase.

Inventive Principle:

Principle #34Discarding and recovering

3Force

If heavy casing string is used to overcome drag forces in vertical sections, then additional weight is provided, but the casing may buckle or collapse under excessive compression

Engineering Contradiction:

Improvedownward force to overcome dragVSAvoidcasing structural integrity

Core Design Contradiction:

ForceVSStrength

Solution Approach 1:

The buoyancy system provides an upward buoyant force that acts as a counterweight to the downward gravitational force on the casing string. This counterbalancing force reduces the net compressive load on the casing, allowing the casing to overcome drag forces during lowering without experiencing excessive compression that would cause buckling or collapse.

Inventive Principle:

Principle #8Anti-weight (Counterweight)

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 system effectively reduces debris generation and equipment damage by allowing controlled release and dissolution, maintaining wellbore integrity and facilitating smooth cementing operations while providing buoyancy support, thus enhancing operational safety and efficiency.

Implementation Method 1

at least another portion of the at least one outer tubular comprises a dissolvable portion for controllably degrading

Methodology Applied

Scientific EffectDissolution:

Implementation Method 2

The air chamber creates a buoyant effect that reduces the casing weight, resulting in less drag between the casing and formation

Methodology Applied

Scientific EffectBuoyancy: Archimedes' Principle (Buoyancy)

Data Source

PatentUS12006786B2Modified casing buoyancy system and methods of use

Publication Date: 2024.06.11 CANADIAN CASING ACCESSORIES INC

AI summary

According to embodiments, a modified casing buoyancy system is provided for use as either one or both a casing buoyancy tool during casing operations and a cement plug during cementing operations, the apparatus being operably connected to a casing string and having at least two tubulars, wherein a portion of at least one (outer) tubular comprises at least one connector for controllably releasing said tubular downhole, and at least a portion of the other (inner) tubular comprises a dissolvable portion for controllably degrading thereof.