Frangible Degradable Alloy for Borehole Tool Self-Removal

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Solution Overview

Problem

Current borehole tools used in geologic environments for operations like drilling, cementing, and fracturing lack materials that can effectively degrade in response to environmental conditions, leading to inefficiencies and potential damage due to environmentally-assisted cracking and stress corrosion cracking.

Innovation Solution

Development of a frangible degradable alloy and material that includes an oxidizable base element and alloying elements, such as aluminum, magnesium, and titanium, which can form passivating oxide layers and degrade via mechanisms like stress corrosion cracking and hydrogen embrittlement, allowing for controlled fracture and removal in aqueous environments.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional non-degradable materials are used in borehole tools, then structural strength and durability are maintained, but environmental stress corrosion cracking and damage occur due to inability to degrade

Engineering Contradiction:

Improveresistance to environmental stress corrosion crackingVSAvoidstructural strength

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The patent changes the material parameters by using age-hardenable alloys with specific compositions (e.g., Al-Zn-Mg-Cu series) that undergo controlled phase transformations. The material transitions from a strong initial state to a degraded state through controlled aging processes, allowing it to maintain strength during service and then degrade when needed, resolving the contradiction between maintaining strength and resisting environmental damage.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent employs composite material structures combining age-hardenable alloys with specific microstructures and potentially composite coatings or treatments. These composite structures provide both the necessary structural strength during operation and the ability to degrade through controlled mechanisms like stress corrosion cracking, thereby resolving the contradiction between strength and environmental resistance.

Inventive Principle:

Principle #40Composite materials

2Ease of operation

If degradable materials are introduced to enable controlled fracture, then self-removal capability is achieved, but material reliability during service is compromised

Engineering Contradiction:

Improveself-removal capabilityVSAvoidservice reliability

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The patent applies preliminary action by pre-hardening the age-hardenable alloy to a high-strength state before deployment. The material is aged and strengthened in advance, ensuring maximum strength and reliability during service. After service, the same material can be deliberately degraded through controlled exposure to environmental conditions, enabling self-removal. This temporal separation of strengthening and degradation actions resolves the contradiction between reliability and self-removal capability.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent introduces dynamic behavior to the material by utilizing age-hardenable alloys that can transition between different mechanical states. The material dynamically adjusts its properties: remaining strong during service and then transitioning to a degraded state for self-removal. This dynamic capability allows the material to fulfill both reliable service and self-removal functions, resolving the contradiction between these opposing requirements.

Inventive Principle:

Principle #15Dynamics

3Duration of action of moving object

If age-hardenable materials are used prior to predetermined age hardening time, then controlled degradation is achieved, but premature degradation may occur before intended service

Engineering Contradiction:

Improveservice durationVSAvoidresistance to premature degradation

Core Design Contradiction:

Duration of action of moving objectVSReliability

Solution Approach 1:

The patent utilizes parameter changes by controlling the aging time and temperature parameters of the age-hardenable alloy. The material is deployed in a semi-aged state and then undergoes controlled aging during service. By carefully managing these temporal and thermal parameters, the material maintains stability during the intended service duration and only degrades after the predetermined time, resolving the contradiction between service duration and resistance to premature degradation.

Inventive Principle:

Principle #35Parameter changes

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 degradable materials enable controlled degradation and fracture of borehole tools, facilitating operations like multi-stage fracturing and cementing by reducing the risk of damage from environmental stressors and allowing for self-removal without altering external downhole stresses.

Implementation Method 1

a frangible degradable alloy that includes an oxidizable base element and at least one alloying element

Methodology Applied

Scientific EffectOxidation: Oxidation

Implementation Method 2

degrading the age-hardenable material via exposure to an aqueous solution

Methodology Applied

Scientific EffectStress corrosion cracking:

Implementation Method 3

form hydrogen traps and form grain boundaries that transport aqueous solution

Methodology Applied

Scientific EffectHydrogen embrittlement:

Data Source

PatentUS11208868B2Frangible degradable materials

Publication Date: 2021.12.28 SCHLUMBERGER TECH CORP

AI summary

A borehole tool can include a frangible degradable alloy that includes an oxidizable base element and at least one alloying element.