Packer Sealing Element Mandrel Interference Fit
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Solution Overview
Problem
Conventional packers in the oil and gas industry face seal failure due to high temperature environments, cooling, and setting backlash, as well as self-setting issues with high flow rates, often exacerbated by fluid leakage between the packing element and mandrel.
Innovation Solution
A sealing element with an annular body and internal surface defining tapered ridges for an interference fit with the mandrel, external surface grooves that close to maintain pressure, and internal surface grooves with insert rings to enhance contact pressure and prevent fluid trapping, along with back-up layers and removable leak paths to ensure reliability under adverse conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the sealing element is used in high temperature environment, then the seal may be initially formed, but the seal fails when the environment subsequently cools due to thermal contraction
Solution Approach 1:
The patent modifies the physical parameters of the sealing element by incorporating a compressible foam material that can change its density and volume in response to temperature fluctuations. This allows the seal to maintain contact pressure with the wellbore wall despite thermal contraction during cooling cycles.
Solution Approach 2:
The patent pre-compresses the foam sealing element during installation to store elastic energy. This pre-compression acts as a cushion that compensates for subsequent thermal contraction, maintaining seal integrity without requiring additional active adjustment mechanisms.
2Reliability
If the packer is subject to setting backlash, then the packer can be installed, but the pressure on the sealing element reduces causing seal failure
Solution Approach 1:
The foam material's compressibility parameter is utilized to maintain constant contact pressure. As the packer undergoes setting backlash, the foam's elastic recovery continuously compensates for pressure loss, maintaining the sealing force without requiring rigid mechanical constraints.
Solution Approach 2:
The patent transitions from a static rigid seal to a dynamic foam-based seal that can continuously adjust its compression state. The foam's viscoelastic properties allow it to dynamically respond to changing load conditions, maintaining seal pressure despite backlash-induced force variations.
3Productivity
If high flow rates flow past an unset packer, then fluid transport is enabled, but the packer self-sets due to fluid pressure
Solution Approach 1:
The patent applies different properties to different parts of the system: the foam seal is made highly compressible to absorb pressure fluctuations, while the mandrel and outer structure remain rigid to maintain geometric stability. This local differentiation allows high flow rates without triggering self-setting.
Solution Approach 2:
The compressible foam acts as a pressure buffer that absorbs fluid pressure spikes before they can propagate to the mandrel. This beforehand cushioning prevents the fluid pressure from reaching the threshold that would cause premature self-setting of the packer.
4Stability of the object's composition
If fluid flows between the packing element and mandrel, then pressure equalization occurs, but voids and trapped fluids are created reducing control
Solution Approach 1:
The patent extracts the fluid barrier function from the interface between the seal and mandrel by using the foam's internal porosity to absorb and hold fluids. This prevents fluid from accumulating in the annular space between the seal and mandrel, eliminating voids and maintaining material control.
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 provides improved stability and reliability by preventing fluid entry between the mandrel and sealing element, maintaining seal integrity during high pressure and temperature fluctuations, and ensuring consistent contact pressure, even with reduced setting pressure.
Implementation Method 1
the internal surface defines first and second regions, the throughbore diameter of the regions being less than the mandrel diameter... the interference fit between the regions and the mandrel prevents fluid from entering between the mandrel and the element
Implementation Method 2
Each packer generally comprises an elastomeric sealing element which, when axially compressed, expands radially outwards from a mandrel into engagement with, for example, a well bore wall
Implementation Method 3
the external surface groove walls come into engagement when the/each external surface groove closes up... the/each external surface groove will open up, at least partially, to 'soak-up' the reduction in setting pressure
Data Source
AI summary
A sealing element for a packer is described. The sealing element comprises an annular body having an internal surface defining a throughbore, the internal surface adapted to engage a mandrel having a mandrel diameter. The annular body internal surface defines first and second regions, the throughbore diameter of the regions being less than the mandrel diameter.