Eutectic Salt Seal Element for Wellbore Annulus
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Solution Overview
Problem
Existing wellbore sealing technologies face limitations in sealing small clearances and handling axial loads due to material constraints, leading to complexity, cost, and reliability issues, especially when dealing with pressure differentials and rough surfaces.
Innovation Solution
A seal element utilizing a eutectic salt material contained in a durable, flexible bag that can be axially compressed or extended, allowing the salt to melt and solidify for sealing and unsealing, providing a re-settable and adaptable sealing solution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If bulk expansion seal elements using elastomers are employed, then sealing capability is improved, but the ability to seal small clearances and handle axial loads is limited
Solution Approach 1:
The patent employs ductile metal materials that undergo significant plastic deformation under axial compression, changing the mechanical parameters of the seal element to enable sealing of small clearances. The metal's ability to flow and conform under pressure allows it to adapt to varying annular gaps that elastomers cannot accommodate.
Solution Approach 2:
The invention uses composite structures combining ductile metal seal elements with supporting mandrels and retrieval mechanisms. This composite approach allows the metal to provide sealing conformability while the mandrel structure provides axial load support and retrieval capability, overcoming the limitations of pure elastomer or pure metal solutions.
2Manufacturing precision
If ductile metal seal elements are used, then sealing of small clearances is improved, but retrieval becomes difficult due to irreversible deformation
Solution Approach 1:
The seal element is segmented into a deformable metal sealing portion and a rigid mandrel structure. The metal portion provides the sealing function through irreversible deformation, while the separate mandrel structure maintains structural integrity and provides attachment points for retrieval, allowing the sealed device to be pulled back without requiring the seal material itself to be elastic.
Solution Approach 2:
The device is designed with pre-integrated retrieval mechanisms attached to the mandrel structure before deployment. These mechanisms (such as slips or mechanical anchors) are prepared in advance to engage with the wellbore structure, enabling retrieval without requiring the seal material to reversibly deform.
3Reliability
If axial load management systems are added to handle pressure differentials, then sealing reliability under pressure is improved, but device complexity and cost increase
Solution Approach 1:
The axial load management function is merged with the sealing element structure itself. The rigid mandrel that provides structural support during deployment is the same structure that transmits and manages axial loads from pressure differentials. This integration eliminates the need for separate anchoring systems, reducing complexity while maintaining reliability.
Solution Approach 2:
The mandrel structure serves multiple functions: it provides structural support during run-in, transmits axial loads from pressure differentials, and provides attachment points for retrieval mechanisms. This multi-functionality reduces the overall device complexity by eliminating the need for dedicated components for each function.
4Reliability
If significant annular space is allocated for sealing and mechanical-retaining hardware, then sealing capability is improved, but maximum internal-bore diameter is reduced
Solution Approach 1:
The ductile metal seal element acts as a flexible shell that can be compressed axially to expand radially, conforming to the annular space available. This flexible approach allows the seal to adapt to the available clearance without requiring large predetermined dimensions, maximizing the usable internal-bore diameter.
Solution Approach 2:
The seal element transitions from a compact, low-profile state during run-in to an expanded, sealing state after deployment. This dynamic transformation allows the device to minimize its dimension during insertion while providing full sealing capability when installed, effectively increasing the maximum internal-bore diameter that can be accommodated.
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 eutectic salt seal element effectively seals wellbores with improved adaptability and durability, accommodating eccentric conditions and high temperatures, while being retrievable without milling, thus overcoming the limitations of existing technologies.
Implementation Method 1
a eutectic material contained in a flexible bag which may be heated to melt the salt
Implementation Method 2
allowing the salt to melt and solidify for sealing and unsealing
Implementation Method 3
The salt may be any eutectic phase changing salt capable of withstanding the wellbore operating conditions and the latent heat of the salt is sufficient to expand the flexible bag to seal the wellbore
Data Source
AI summary
The present invention relates to a seal element for a wellbore which includes a support member, a bag positioned on the support member and a eutectic material positionable in the bag. The bag may be axially compressed and axially extended along the support member thereby permitting sealing and unsealing of an annulus in a wellbore. The eutectic material may be a phase changing salt.