Hydraulic Decomposable Well Plug for Explosive-Free Removal
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Solution Overview
Problem
Existing plug devices for testing oil and gas wells require explosive charges for safe and calculable removal, which is undesirable due to stringent regulations on explosives and is unreliable in operations from floating rigs, especially concerning the unpredictability of plug removal and high operating costs.
Innovation Solution
A plug device comprising a sleeve-shaped element with decomposable strata and supporting bodies, where liquid-filled chambers are pressurized and connected to relief grooves with a hydraulic slide valve system, allowing controlled decomposition by pressure change, eliminating the need for explosive charges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If explosive charges are used to remove the test plug, then the plug can be safely and calculably removed, but the use becomes subject to stringent regulations and is unreliable in operations from floating rigs
Solution Approach 1:
The patent replaces the explosive charge system with a hydraulic actuation system. A piston moved by hydraulic pressure from well fluids mechanically activates the decomposition mechanism, eliminating the need for explosives while maintaining reliable and controllable plug removal across various operating conditions including floating rigs.
Solution Approach 2:
The invention utilizes hydraulic pressure from well fluids to drive a piston that activates the plug decomposition. The hydraulic system provides reliable actuation without explosives, allowing controlled removal adapted to different operating environments including floating rigs where explosive use is problematic.
2Strength
If the plug is made of glass layers with hardening treatment, then it possesses strength to resist pressure stresses, but it becomes brittle
Solution Approach 1:
The glass plug is divided into multiple disc-shaped layers stacked together. This segmentation allows each layer to be relatively thin and manageable, while the collective structure resists pressure. The layered design with intermediate films enables controlled decomposition without requiring each individual glass layer to withstand extreme stresses alone.
Solution Approach 2:
The plug combines glass layers with intermediate films of plastic, felt, or paper, and laminating adhesives to create a composite structure. This composite material approach allows the glass to provide pressure resistance while the softer intermediate materials absorb stress concentrations and reduce brittleness, enabling the plug to withstand well pressures while remaining decomposable.
3Adaptability or versatility
If chemical dissolution is used to remove the rubber plug, then the plug can be removed without explosives, but the process is too slow and unreliable for floating rig operations
Solution Approach 1:
The patent replaces chemical dissolution with a mechanical actuation system. A piston driven by hydraulic pressure mechanically activates the decomposition of glass layers through pin devices that concentrate force on specific points, providing rapid and reliable plug removal suitable for floating rig operations where time is critical.
Solution Approach 2:
The decomposition process occurs in a controlled sequence where hydraulic pressure is applied periodically to activate the piston, which then triggers the mechanical breakdown of glass layers. This periodic mechanical action provides predictable and timely plug removal, unlike continuous but slow chemical dissolution.
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 plug device provides a secure seal, withstands high pressures, and can be decomposed in a controlled manner, ensuring predictable free flow in the well without explosives, enhancing safety and flexibility in construction and use.
Implementation Method 1
The closed, liquid-filled chambers may be pressurised. Moreover, pin devices (18) may be provided between the body (2) and the number of glass strata (5, 7, 9), which are arranged to point load the strata when the plug device has to be decomposed.
Implementation Method 2
The body (2) may furthermore be equipped with a number of sealing devices (13), such as an O-ring, which for example may be placed on the outside of the body to prevent liquid from the respective chambers (16) from being drained out of the drainage outlets (8) when the plug device is in a closed position (rest position).
Data Source
Figure 1a~1b
Figure 2a~2b
AI summary
A decomposable sealing device is described for use in liquid-filled pipes or boreholes, which is characterised in that the sealing device comprises a sleeve-shaped element (19) which envelops a number of strata (5, 7, 9) completely or partly in the pipe's radial and a longitudinal direction, comprising layered division of a number of decomposable strata (5, 7, 9) and a number of closed liquid-filled chambers (16) arranged between the strata (5, 7, 9) and where the sleeve-shaped element (19) comprises a body (2) which can be rearranged to establish connection between the respective chambers (16) and one or more grooves (14) in the inner wall of a pipe. A method for decomposing the sealing device is also described.