Oil-Degradable Sealing Elements for Downhole Tool Retrieval
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Solution Overview
Problem
Traditional downhole tools require complex and costly retrieval processes due to their non-degradable sealing elements, which hinder efficient removal from wellbores after operations are complete, as they lack materials capable of expansive or elastic properties necessary for effective sealing.
Innovation Solution
Incorporating an oil-degradable sealing element, composed of an oil-degradable elastomer, which degrades in the wellbore environment, allowing for fluid sealing and subsequent failure without the need for milling or drilling, enabling the tool to drop into a rathole or become indiscernible, thus simplifying removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional non-degradable sealing elements are used, then the sealing element can maintain structural integrity and provide reliable sealing, but the downhole tool requires complex and costly mechanical retrieval operations
Solution Approach 1:
The sealing element's material composition is changed from traditional non-degradable materials to oil-degradable materials, fundamentally altering its chemical stability parameter. This allows the seal to maintain integrity during operation but automatically degrade after completion, eliminating the need for complex mechanical retrieval operations and reducing well intervention complexity
Solution Approach 2:
The sealing element is designed as a disposable component that serves its function temporarily and then degrades naturally in the wellbore environment. This eliminates the need for expensive and time-consuming retrieval operations, converting a permanent component into a temporary one that is discarded after use through natural degradation
2Loss of time
If dissolvable materials are used for the tool body, then retrieval cost and time are reduced, but the material becomes too brittle to provide necessary expansive or elastic properties for sealing
Solution Approach 1:
The downhole tool is segmented into two distinct components with different material properties: a durable tool body that provides structural support and mechanical strength, and a degradable sealing element that provides sealing function. This segmentation allows each component to be optimized independently - the body for strength and the seal for degradability - resolving the contradiction between retrieval ease and sealing performance
Solution Approach 2:
The sealing element is constructed from composite or specially formulated oil-degradable materials that balance mechanical properties with degradability. These materials maintain sufficient elasticity and expansiveness during operation to ensure reliable sealing, while simultaneously being capable of degradation in the wellbore environment to facilitate easy removal without complex retrieval operations
3Ease of operation
If degradable materials are used for both body and sealing element, then complete in-situ degradation is achieved, but the tool may lack structural integrity during operation
Solution Approach 1:
The downhole tool is divided into functional segments with different durability requirements: the tool body is designed to be durable and maintain structural integrity throughout operation and retrieval, while the sealing element is designed to be degradable. This segmentation ensures that structural strength is not compromised while still achieving ease of operation through selective degradation of non-structural components
Solution Approach 2:
Different parts of the downhole tool have different material properties tailored to their specific functions. The tool body uses durable materials for structural support, while the sealing element uses degradable materials for temporary sealing. This local differentiation of material quality allows the tool to maintain overall structural integrity while achieving easy removal through localized degradation where it is most beneficial
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
This approach reduces the time and cost associated with removing downhole tools by allowing them to degrade in situ, eliminating the need for mechanical retrieval and facilitating more efficient well operations.
Implementation Method 1
at least one oil-degradable sealing element composed of an oil-degradable elastomer, wherein the oil-degradable sealing element degrades in the wellbore environment
Data Source
AI summary
Downhole tools comprising a body, wherein at least a portion of the body is degradable when exposed to a wellbore environment; and at least one oil-degradable sealing element composed of an oil-degradable elastomer, wherein the oil-degradable sealing element degrades in the wellbore environment. The oil-degradable elastomer is selected from the group consisting of an oil-degradable natural rubber, an oil-degradable synthetic rubber, and any combination thereof.