Degradable Pipe Plug With Chamber-Triggered Corrosion Control
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Solution Overview
Problem
Existing degradable plugs for oil or gas wells face issues such as uncontrolled corrosion, slow dissolution, obstruction during removal, and limited means for initiating dissolution, leading to increased costs and operational risks.
Innovation Solution
A degradable plug device with an outer plug body and inner plug, featuring a chamber with ports for controlled fluid ingress to initiate corrosion or dissolution, and a shear device for controlled release, allowing for remote actuation and rapid dissolution upon pressure or force thresholds being met.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a magnesium ball is used to block the well, then the blocking function is achieved, but the corrosion is not controllable and may start as soon as it enters the well
Solution Approach 1:
The plug device is divided into an outer plug body and an inner plug, with the inner plug containing a chamber that seals off the degradable material until activation. This segmentation allows the blocking function to be performed while preventing premature corrosion by isolating the degradable material from well fluid until the chamber is intentionally opened.
Solution Approach 2:
The degradable plug device is prepared in advance with a protective structure (outer plug body and sealed chamber) that prevents corrosion during insertion and deployment. The preliminary sealing ensures that when the plug is inserted into the well, the degradable material remains protected until the predetermined time or condition triggers chamber opening.
2Duration of action of stationary object
If a degradable plug is provided to allow controlled dissolution, then the blocking duration can be extended, but the dissolution may not be sufficiently quick when required to be removed
Solution Approach 1:
The plug device transitions from a static sealed state to a dynamic dissolution state through controlled activation. The chamber remains sealed during the blocking phase, then upon receiving a trigger signal (pressure change, mechanical action, or chemical trigger), the chamber opens rapidly to allow well fluid to contact the degradable material, accelerating dissolution when removal is needed.
Solution Approach 2:
The dissolution rate of the plug is controlled by changing parameters such as the surface area exposed to well fluid, the composition of the degradable material, and the chemical environment within the chamber. By adjusting these parameters, the plug can maintain structural integrity for the required blocking duration and then dissolve quickly when activated.
3Stress or pressure
If the plug dissolves slowly to maintain blocking, then pressure can be maintained, but the plug may become stuck or flow downstream causing obstruction
Solution Approach 1:
The chamber acts as an intermediary between the degradable plug material and the well fluid. During the blocking phase, the chamber walls prevent direct contact between the fluid and the plug material, maintaining pressure while preventing uncontrolled dissolution. When activation occurs, the intermediary barrier is removed, allowing rapid dissolution without the risk of gradual sticking or downstream obstruction.
4Device complexity
If limited means are provided for initiating dissolution, then the device structure is simple, but more options are required for controlling plug removal
Solution Approach 1:
The chamber opening mechanism is designed to respond to multiple types of activation signals while maintaining a relatively simple structure. The same chamber can be opened by different means such as pressure changes, mechanical triggers, or chemical signals, providing versatile dissolution initiation options without significantly increasing device complexity. This multi-functionality allows the plug to be adapted to different well conditions and operational requirements.
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
Enables quick and controlled dissolution of the plug, minimizing obstruction and operational risks, while maintaining pressure and ensuring full pipe bore usability post-removal.
Implementation Method 1
initiate corrosion or dissolution of the inner plug from inside the chamber
Implementation Method 2
initiate corrosion or dissolution of the inner plug from inside the chamber
Data Source
AI summary
A degradable plug device for a pipe has an outer plug body and an inner plug for preventing fluid flow through the pipe until the inner plug has been removed from the outer plug body. The outer plug body and the inner plug are of a degradable material. The inner plug has a chamber with at least one port to the exterior of the inner plug. The exposed surfaces of the degradable plug have a protective layer thereon. The inner plug is disposable in at least a first position, in which the inner plug prevents the fluid flow through the pipe. The inner plug is adapted to undergo, in use, a degradation initiation operation such that fluid is able to enter the chamber via the at least one port to initiate corrosion or dissolution of the inner plug from inside the chamber.