Functionally Gradient Composite Downhole Tool for Controlled Removal
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Solution Overview
Problem
Existing wellbore components and tools require frequent replacement due to limited mechanical strength and fracture toughness, making conventional removal methods like milling or drilling time-consuming and expensive, and degradable materials lack suitable mechanical properties for effective use.
Innovation Solution
A composite downhole article is developed with a corrodible core member and a more corrosion-resistant outer member, featuring a composition or density gradient that allows for controlled dissolution in wellbore fluids, enabling rapid removal and reconfiguration of tools without compromising mechanical performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If degradable polymers are used to enable easy removal, then removal ease is improved, but mechanical strength and fracture toughness deteriorate
Solution Approach 1:
The patent applies composite materials by combining a degradable core member (made from degradable alloys or polymers) with a non-degradable outer member (made from conventional wellbore materials). This composite structure allows the tool to achieve both easy removal (through dissolution of the degradable core) and adequate mechanical strength (provided by the non-degradable outer member during operation). The composite design resolves the contradiction by integrating materials with complementary properties.
Solution Approach 2:
The patent segments the tool into distinct functional portions: a degradable core member and a non-degradable outer member. This segmentation allows each portion to perform its specific function - the core provides structural support during operation and enables removal through dissolution, while the outer member provides mechanical strength and protection. The segmentation resolves the contradiction by separating the conflicting requirements into different components.
2Strength
If conventional removal methods (milling or drilling) are used, then mechanical strength is maintained, but removal time and cost increase
Solution Approach 1:
The patent replaces the mechanical removal system (milling or drilling) with a chemical dissolution system. The degradable core member is designed to dissolve in wellbore fluids through chemical reactions, eliminating the need for mechanical cutting operations. This substitution dramatically reduces removal time and cost while maintaining mechanical strength during operation through the non-degradable outer member.
Solution Approach 2:
The patent changes the removal mechanism from mechanical (high energy consumption, time-intensive) to chemical (low energy consumption, rapid). By selecting degradable materials with appropriate dissolution rates and using functionally gradient composite structures, the tool achieves rapid removal through parameter optimization of material composition and structure.
3Ease of operation
If degradable materials are used to enable removal, then removal ease is improved, but mechanical properties at operating temperature deteriorate
Solution Approach 1:
The patent uses composite materials where the non-degradable outer member is selected to maintain mechanical properties at operating temperatures, while the degradable core member enables removal. The outer member acts as a protective shell that maintains structural integrity under downhole conditions, while the core member dissolves when exposed to wellbore fluids, resolving the contradiction between thermal stability and removability.
Solution Approach 2:
The patent applies local quality by giving different portions of the tool different material properties: the outer member has high thermal stability and mechanical strength for operation, while the core member has degradability for removal. This local differentiation of material properties allows each portion to optimize for its specific function without compromising the other.
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 composite design enables wellbore tools to maintain mechanical integrity during operation while allowing for efficient and controlled removal, reducing operational costs and time by utilizing wellbore fluids to dissolve the corrodible core, thus facilitating tool reconfiguration or extraction.
Implementation Method 1
a corrodible core member (30) comprising a first material (32) that is corrodible in a wellbore fluid (24) at a first corrosion rate
Implementation Method 2
an outer member (40) that is disposed on the core member (30) and comprises a second material (42) that is corrodible in the wellbore fluid (24) at a second corrosion rate, wherein the second corrosion rate is less than the first corrosion rate
Data Source
AI summary
A method of making a composite downhole article is disclosed. The method include forming at least one removable core member comprising a first metallic material that is removable in a wellbore fluid at a first removal rate; and disposing at least one outer member on the core member, the outer member comprising a second material that is removable in the wellbore fluid at a second removal rate, wherein the removable core member has a composition gradient or a density gradient, or a combination thereof, and wherein the first removal rate is substantially greater than the second removal rate. A method of using a composite downhole article is also disclosed. The method includes forming a composite downhole article as described above; using the article to perform a first wellbore operation; exposing the article to the wellbore fluid; and selectively removing the second removable member.