Self-Inhibited Swell Packer Compound for Downhole Sealing
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Solution Overview
Problem
Downhole packers often prematurely swell and become stuck in boreholes due to uncontrolled expansion, leading to costly and time-consuming extraction processes, as they absorb fluid before reaching the target depth.
Innovation Solution
A downhole sealant composition with a primary crosslink network and a transient secondary crosslink network, which can be decomposed in response to conditions like temperature, pressure, or pH, regulating the swell rate to ensure controlled expansion and effective sealing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the packer absorbs fluid to expand and seal the borehole, then the sealing effectiveness is improved, but the packer may swell prematurely and become stuck before reaching the target depth
Solution Approach 1:
The packer employs a dynamic crosslinking system where the crosslink density of the polymer changes over time. Initially, the polymer has a lower crosslink density allowing controlled swelling, and then undergoes a chemical transformation to increase crosslink density, locking the packer in its expanded state to prevent premature swelling while maintaining sealing effectiveness
Solution Approach 2:
The invention changes the chemical parameters of the polymer by transforming the crosslinking agent from an uncrosslinked state to a crosslinked state. This parameter change increases the crosslink density over time, regulating the swell rate to prevent premature expansion while ensuring eventual sealing at the target depth
2Reliability
If the packer expands by absorbing fluid, then the seal is formed, but the packer may become stuck in an undesired position requiring costly extraction
Solution Approach 1:
The packer is equipped with a preliminary chemical system (uncrosslinked crosslinking agent) that prepares the polymer for controlled expansion. Before the packer reaches the target depth, the crosslinking reaction is initiated, creating a progressively increasing crosslink density that prevents premature swelling and eliminates the need for costly extraction operations
3Speed
If the crosslink density is increased to prevent premature swelling, then the swell rate is controlled, but the sealing effectiveness may be reduced
Solution Approach 1:
The system dynamically adjusts crosslink density over time rather than maintaining a static high crosslink density. The crosslinking reaction progresses during the packer's descent, initially allowing controlled swelling and then increasing crosslink density to lock the expanded position, thereby maintaining both swell rate control and sealing effectiveness
Solution Approach 2:
The uncrosslinked crosslinking agent is preliminarily incorporated into the polymer matrix in a dormant state. This preliminary preparation allows the polymer to maintain appropriate swell characteristics during descent, and the crosslinking reaction is then activated to ensure effective sealing at the target depth without compromising either swell control or sealing effectiveness
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 composition allows for controlled swell rates, preventing premature swelling and ensuring the packer reaches its intended position for effective sealing, reducing the risk of becoming stuck and simplifying extraction processes.
Implementation Method 1
decomposing a secondary crosslink network of the absorbent material in response to a condition to regulate the swell rate of the downhole sealant
Implementation Method 2
the packer is in contact with the fluid in the borehole... when the packer absorbs this fluid and expands
Implementation Method 3
a primary crosslink network comprising primary bonds between chains of the polymer
Data Source
AI summary
A downhole sealant includes a composition that includes a polymer; an absorbent material; a primary crosslink network including primary bonds between chains of the polymer; and a secondary crosslink network which is transient. A method of regulating the swell rate of the downhole sealant includes disposing a downhole sealant comprising a polymer and an absorbent material in a borehole; maintaining a primary crosslink network of the polymer; and decomposing a secondary crosslink network of the absorbent material in response to a condition to regulate the swell rate of the downhole sealant.