Downhole Article Degradation Using Reducing Agents

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Solution Overview

Problem

Current methods for removing downhole components or tools from oil and gas wells are time-consuming and expensive, as they require milling or drilling, and existing degradable materials either corrode too quickly or too slowly under downhole conditions.

Innovation Solution

A method involving a composition with a reducing agent, such as ascorbic acid or erythorbic acid, is used to selectively and controllably degrade downhole articles containing electrolytic materials, allowing for controlled removal without obstructing fluid flow and providing benefits for the downhole environment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If strong mineral acids are used to degrade metal alloys, then the corrosion rate is too fast, but if brine is used, then the corrosion rate is too slow under downhole conditions

Engineering Contradiction:

Improvecorrosion rateVSAvoidcontrolled degradation

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent changes the chemical parameters of the degrading agent by using metal ions (Fe2+, Fe3+, Cu2+, Mn2+, Ni2+, Co3+, Cr3+, Cr6+, Cr2+, Zn2+) in aqueous solutions instead of traditional mineral acids or brine. This parameter change enables controlled corrosion rates that are neither too fast nor too slow, achieving optimal degradation performance under downhole conditions.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent introduces metal ions as intermediary substances that mediate the corrosion process. These metal ions act as catalysts that control the degradation rate of the metal alloy, providing a balanced corrosion rate that is faster than brine but slower and more controlled than strong mineral acids.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Productivity

If milling or drilling is used to remove downhole components, then the component is removed, but the operation is time consuming and expensive

Engineering Contradiction:

Improveremoval speedVSAvoidremoval time

Core Design Contradiction:

ProductivityVSLoss of time

Solution Approach 1:

The patent replaces the mechanical removal system (milling or drilling) with a chemical degradation system. By using metal ions in aqueous solutions to controllably corrode the metal alloy components, the system eliminates the need for time-consuming mechanical cutting operations, achieving faster and more cost-effective removal.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent enables the downhole component to self-degrade through controlled corrosion. The metal alloy component automatically degrades when exposed to the metal ion-containing aqueous solution, eliminating the need for external mechanical intervention and reducing removal time and costs.

Inventive Principle:

Principle #25Self-service

3Ease of operation

If degradable metal alloys are used, then the component can be removed by dissolution, but the corrosion rate must be precisely controlled

Engineering Contradiction:

Improveremoval processVSAvoidcorrosion rate control

Core Design Contradiction:

Ease of operationVSManufacturing precision

Solution Approach 1:

The patent achieves precise control over corrosion rates by varying the parameters of the aqueous solution, specifically the type and concentration of metal ions (Fe2+, Fe3+, Cu2+, Mn2+, Ni2+, Co3+, Cr3+, Cr6+, Cr2+, Zn2+). This parameter control allows the corrosion rate to be optimized for different downhole conditions and component types.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent employs feedback mechanisms to monitor and adjust the corrosion process. The metal ion-containing aqueous solution can be designed with specific concentrations and compositions that provide feedback control over the corrosion rate, ensuring optimal degradation performance and preventing either excessive corrosion or insufficient degradation.

Inventive Principle:

Principle #23Feedback

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 method effectively degrades downhole components over time, exposing beneficial surfaces and maintaining functionality, while being environmentally benign and optimizing corrosion rates between strong and mild corrosives, thus reducing operational costs and time.

Implementation Method 1

A method for degrading a downhole article comprises exposing the downhole article comprising a controlled electrolytic material to a composition comprising: water; and a reducing agent

Methodology Applied

Scientific EffectReduction: Reduction

Implementation Method 2

The degradable materials that have been proposed include certain degradable metal alloys formed from reactive metals, such as aluminum, together with other alloy constituents... These materials may be formed by melting powders of the constituents and then solidifying the melt to form the alloy

Methodology Applied

Scientific EffectElectrochemical corrosion: Electrolysis

Data Source

PatentUS10059867B2Agents for enhanced degradation of controlled electrolytic material

Publication Date: 2018.08.28 BAKER HUGHES CO

AI summary

A method for degrading a downhole article includes exposing the downhole article comprising a controlled electrolytic material to a composition that comprises a reducing agent. The method also includes contacting the downhole article with the reducing agent to degrade the downhole article. Additionally, a composition for degrading a downhole article includes water, chelant, metal ions, and a reducing agent that includes ascorbic acid, erythorbic acid, a derivative thereof, a salt thereof, or a combination thereof.