Swellable Packer With Controlled Swelling Rate
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Solution Overview
Problem
Existing swellable packers used in downhole environments swell rapidly, limiting the time available for completion operations, as they expand within one to two days when exposed to hydrocarbon-based fluids, necessitating a solution for delayed and controlled swelling.
Innovation Solution
A sealing system comprising a mandrel, a swellable element, and a swell control element with a polymeric matrix impermeable to oil and water, incorporating a channel inducer such as carbon nanotubes, hollow fibers, or degradable polymers, which delays the swelling of the swellable element by controlling fluid permeation and swelling rate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a swellable element is used to seal the borehole, then sealing effectiveness is improved, but the swelling occurs too rapidly (within 1-2 days), limiting the time available for completion operations
Solution Approach 1:
The packer element is divided into two functional layers: an outer swell control layer and an inner swellable element layer. This segmentation allows the outer layer to regulate fluid permeation rate, thereby controlling the swelling timing of the inner element to provide a delayed swelling period of several days to weeks while maintaining effective sealing.
Solution Approach 2:
The patent modifies the permeability parameter of the packer by introducing a swell control layer with specific permeability characteristics. This layer controls the rate at which downhole fluids reach the swellable element, thereby adjusting the swelling timeline from rapid (1-2 days) to controlled (several days to weeks) without compromising sealing effectiveness.
2Productivity
If the swellable element is made more permeable to allow faster swelling, then sealing is achieved quicker, but the swelling occurs too rapidly reducing operational time
Solution Approach 1:
The packer structure implements local quality differentiation where the outer swell control layer has low permeability to delay fluid access, while the inner swellable element maintains high swellability. This localized property assignment allows controlled timing of swelling while preserving the ultimate sealing capability when swelling does occur.
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 system effectively delays the swelling of the swellable element, allowing for extended operation time by tuning the permeability of the swell control element, ensuring the swellable element swells within a desired timeframe, typically less than 25 days, while maintaining mechanical strength and preventing rupture.
Implementation Method 1
EPDM rubber often swells rapidly in the oil or oil based fluids
Implementation Method 2
a swell control element disposed on a surface of the swellable element and configured to delay swelling of the swellable element; wherein the swell control element comprises a polymeric matrix that is impermeable to oil, water, or a combination thereof
Data Source
AI summary
A sealing system for a flow channel is disclosed. The sealing system includes a mandrel; a swellable element disposed about the mandrel; and a swell control element disposed on a surface of the swellable element and configured to delay swelling of the swellable element. The swell control element contains a polymeric matrix that is impermeable to oil, water, or a combination thereof; and a channel inducer dispersed in the polymeric matrix, the channel inducer including carbon nanotubes, a hollow fiber, an oil swellable material, or a combination comprising at least one of the foregoing.