Packer Cup Assembly Debris Exclusion and Pressure Equalization
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Solution Overview
Problem
Mechanically set packers face issues with debris exclusion from the tieback extension and setting sleeve, leading to failure in setting the packer due to fine grit and solid particles in the drilling mud, which can cause the spring-loaded dogs to jam and prevent pressure equalization, potentially resulting in trapped pressure that poses a safety risk during disassembly.
Innovation Solution
A downhole oriented packer cup assembly that self-energizes to maintain debris exclusion after pressure equalization, featuring a dual acting rupture disc that relieves trapped pressure by bursting inwardly if equalization fails and outwardly when the packer is removed, ensuring safe disassembly and preventing tool collapse.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a debris barrier is used to exclude fine grit from the setting sleeve, then the spring-loaded dog mechanism is protected from fouling, but pressure equalization is prevented leading to trapped pressure and potential tool collapse
Solution Approach 1:
The debris barrier is divided into two functional zones: an upper debris-catchment section with packer cups oriented to trap solids, and a lower pressure-equalization section with perforations or porous material that allows fluid passage. This segmentation enables the barrier to simultaneously exclude debris while permitting pressure equalization, resolving the contradiction between protection and pressure balance.
Solution Approach 2:
Different portions of the debris barrier have different properties: the upper portion has solid cup structures for debris exclusion, while the lower portion has open perforations or porous characteristics for pressure equalization. This local differentiation allows each zone to perform its specific function optimally without interfering with the other.
2Reliability
If the packer cup is oriented uphole to accumulate debris, then debris exclusion is improved, but pressure equalization from above to below is prevented
Solution Approach 1:
The packer cup assembly is segmented into an upper cup portion for debris accumulation and a lower portion with pressure-equalization features. The cup structure is positioned to face uphole for capturing debris, while the lower section incorporates perforations or porous material that allows pressure equalization to occur beneath the cup, resolving the contradiction between debris trapping and pressure balance.
Solution Approach 2:
The lower portion of the packer cup acts as an intermediary element that mediates between the debris-catchment function and the pressure-equalization requirement. It allows pressure to pass through while maintaining the debris barrier function, enabling both objectives to be achieved simultaneously.
3Object-affected harmful factors
If a foam material is used to span the annular gap for pressure equalization, then pressure equalization is enabled, but the foam may plug with particulates and fail to equalize pressure
Solution Approach 1:
Instead of using foam material that can plug with particulates, the invention employs a debris barrier with controlled porosity in the form of perforations or a porous screen structure. This allows pressure to equalize through the barrier while the larger pore sizes and open structure prevent particulate plugging, maintaining reliable pressure equalization in grit-laden environments.
Solution Approach 2:
The debris barrier has different structural qualities at different locations: the upper portion has solid cup structures for debris exclusion, while the lower portion has open perforations or porous characteristics specifically designed for pressure equalization without plugging. This local quality differentiation resolves the contradiction between pressure equalization and particulate resistance.
4Object-affected harmful factors
If a dual acting rupture disc is added to relieve trapped pressure, then safety is improved, but device complexity increases
Solution Approach 1:
The debris barrier is designed with multi-functionality, serving both as a debris-catchment structure and as a pressure-equalization device through its integrated perforations or porous lower section. This eliminates the need for separate pressure-relief mechanisms in many cases, reducing overall device complexity while maintaining safety.
Solution Approach 2:
The dual-acting rupture disc is designed as a backup safety mechanism that activates only if the primary pressure-equalization features fail. It provides beforehand protection against trapped pressure by automatically rupturing to equalize pressure if the debris barrier or packer cup fails to allow pressure passage, ensuring safety without requiring complex active control systems.
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 solution effectively prevents debris entry into the setting sleeve, ensures pressure equalization, and safely releases trapped pressure, enabling successful packer deployment and disassembly without risking surface personnel, while withstanding harsh environments.
Implementation Method 1
As the tool is run in the hole the packer cup flexes as the rising hydrostatic pressure equalizes across the cup into what started as a zone with atmospheric pressure inside the packer setting sleeve
Implementation Method 2
the dual acting rupture disc breaks inwardly into the setting sleeve so that pressure is equalized. If the packer is never set after being lowered to depth and the pressure from the setting sleeve has to be equalized into the annulus or else there is a chance that such trapped pressure will remain if the tool is later disassembled at the surface. The dual acting rupture disc breaks outwardly as the unset packer with the running tool are removed together.
Data Source
AI summary
An annular seal for a setting tool in a packer tieback extension comprises a downhole oriented packer cup assembly. As the tool is run in the hole the packer cup flexes as the rising hydrostatic pressure equalizes across the cup into what started as a zone with atmospheric pressure inside the packer tieback extension. Once the pressure is equalized the self energizing feature of the packer cup maintains grit and debris in the mud from entering the tieback extension where the spring loaded dogs of the setting tool are held in a retracted position. If the seal fails to equalize and allows a large differential across the setting sleeve from the surrounding annulus, the rupture disc breaks inwardly into the tieback extension so that pressure is equalized. If the packer is never set after being lowered to depth and the pressure from the tieback extension is equalized into the annulus.