Degradable Pin Protection in Annular Well Isolation Systems
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Solution Overview
Problem
Current well isolation systems face challenges in maintaining effective sealing under varying temperatures and pressures, particularly in non-cylindrical well sections and deep offshore wells, where pressure differentials can cause membrane collapse or loss of sealing contact, leading to potential well damage and ecological risks.
Innovation Solution
A fluid control device with an expandable liner and a three-way valve system that includes a degradable immobilization mechanism and a non-return valve, allowing communication between the annular volume and the liner only after swelling has commenced, ensuring consistent sealing regardless of pressure changes and temperature fluctuations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a degradable pin is used to maintain initial positioning without fluid communication, then the liner can be properly positioned and sealed, but the pin may degrade prematurely due to exposure to degrading fluid, causing loss of positioning and potential well damage
Solution Approach 1:
The system is divided into separate functional zones: a protected cavity housing the degradable pin and positioning mechanism, and a discharge pipe introducing degrading fluid. The protection means (sealing element) segments the fluid access, allowing the pin to fulfill its positioning function for the required duration before controlled degradation begins.
Solution Approach 2:
The liner is initially positioned and sealed by the degradable pin before degradation occurs. The pin performs its positioning function in advance, establishing the necessary sealing configuration. Only after this preliminary action is complete does the pin begin to degrade, ensuring reliable initial sealing while allowing eventual degradation.
2Reliability
If fluid communication is established early to enable liner swelling, then the liner expands to provide sealing, but the degradable pin degrades prematurely causing loss of initial positioning control
Solution Approach 1:
The fluid pathway is segmented into a protected cavity (isolating the pin initially) and a discharge pipe. The sealing element controls when fluid can access the pin, creating distinct temporal phases: first positioning control, then controlled degradation after swelling commences.
Solution Approach 2:
The liner swelling action is initiated before pin degradation. Fluid is introduced to enable liner expansion and sealing establishment. Only after this preliminary swelling action begins does the pin start to degrade, ensuring the liner maintains its sealing function while the pin gradually releases its positioning constraint.
3Productivity
If the degradable pin is exposed to degrading fluid from the beginning, then the pin degrades quickly, but the liner loses its initial positioning and sealing capability before proper installation
Solution Approach 1:
The pin performs its positioning function in advance, establishing reliable initial positioning and sealing capability. The protected cavity and sealing element ensure the pin remains intact during installation and initial operation. Only after the liner is properly positioned and swelling commences does the pin begin to degrade, maintaining reliability throughout the critical initial phase.
Solution Approach 2:
The system segments fluid access to the pin into two phases: a protected phase during installation and positioning where the pin maintains integrity, and a degradation phase after swelling commences. The sealing element and protected cavity structure create this temporal segmentation, allowing controlled timing of degradation to match the installation sequence.
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 device ensures reliable annular isolation by maintaining communication between the annular volume and the liner, even if the maximum swelling pressure is not attained, and prevents premature degradation, thus avoiding issues related to pressure differentials and temperature changes, ensuring the integrity of the well casing.
Implementation Method 1
degradable immobilization means, secured in translation with the piston, said degradable immobilization means in an initial state maintaining the piston in a first position such that the piston avoids communication between the first and the second pipes
Implementation Method 2
said means, after degradation, releasing the piston such that the piston occupies a second position such that communication between the first and the second pipes is enabled
Implementation Method 3
an expandable liner placed on a casing and an assembly adapted to control the feed of the inner volume of the liner by means of pressurized fluid coming from the casing, via a passage passing through the wall of the casing, to expand the liner radially outward
Implementation Method 4
said valve comprising a body which defines a chamber in which terminate a first and a second communication pipe respectively associated inside the expandable liner and the annular space located outside the casing
Data Source
AI summary
The invention relates to a fluid control device (500) for treating a well, to expand a liner (100) radially outward, said device comprising a piston (550) translatably mounted in said chamber (320), and degradable immobilization means (590), secured in translation with the piston (550), wherein the degradable immobilization means (590) are movable in translation in a cavity (700), wherein the device comprises protection means (800) isolating the cavity (700) from a discharge pipe (810) configured to introduce fluid degrading the pin (590) in said cavity (700), such that, in the initial state, the protection means (800) protect said degradable immobilization means (590), the protection means (800) being configured to break when the pressure in the cavity reaches a threshold pressure gap (ΔPs) allowing degradation of the degradable immobilization means (900).