Pyrotechnic Well Barrier Formation via Replenishment String
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Solution Overview
Problem
Existing well plugging and abandonment (P&A) technologies face challenges in creating a permanent, impermeable, and chemically resistant barrier that maintains long-term integrity and ductility, while also ensuring bonding to steel and withstanding mechanical loads.
Innovation Solution
A well tool system comprising a pyrotechnic mixture of bismuth oxide and aluminum, ignited by an ignition device, which generates heat to melt and solidify well components, forming a cap-rock to cap-rock permanent barrier. The system includes a replenishment string with an elevating device to control the movement of the pyrotechnic mixture towards the heat generating process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a heat generating mixture (pyrotechnic mixture) is used to melt and form a permanent barrier, then the barrier achieves impermeability and chemical resistance, but the process requires precise control of material replenishment to maintain barrier integrity and avoid defects
Solution Approach 1:
The replenishment string is pre-positioned and connected to the well tool device before the heat generating process begins. This preliminary arrangement ensures that additional pyrotechnic mixture can be supplied to the reaction zone without requiring complex real-time delivery systems, thereby maintaining barrier integrity while controlling system complexity
Solution Approach 2:
The elevating device dynamically controls the movement of the replenishment string during the heat generating process. This dynamic adjustment allows precise regulation of material supply rate to match the consumption rate, ensuring consistent barrier formation and preventing defects from improper material replenishment
2Duration of action of moving object
If the pyrotechnic mixture is contained in a compact well tool device, then the device can be easily deployed, but the duration of the heat generating process is limited by the initial mixture quantity
Solution Approach 1:
The pyrotechnic mixture is divided into two segments: an initial quantity contained in the well tool device for immediate action, and an additional quantity contained in the separate replenishment string. This segmentation allows the heat generating process to continue for an extended duration without requiring a proportionally larger initial device volume, as the replenishment string can be supplied separately and fed into the reaction zone as needed
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 efficiently forms a permanent, impermeable barrier that meets technical and regulatory requirements, ensuring long-term integrity and ductility, while also bonding effectively to steel and withstanding mechanical loads.
Implementation Method 1
a heat generating process, wherein the heat generating process is configured to melt the surroundings at the location of the well tool device in the well
Implementation Method 2
the heat generating process is configured to melt the surroundings at the location of the well tool device in the well. The result after the ignition is shown in FIG. 1b. Here it is shown that the elements of the well, i.e. inner casing IC, cement CE and cap rock CR have melted and thereafter hardened into one solid permanent well barrier PB
Data Source
AI summary
The present invention relates to a well tool system for forming a permanent barrier in a well, the system comprising: a well tool device comprising a pyrotechnic mixture and an ignition device provided within or adjacent to the pyrotechnic mixture; a tool string connected above the well tool device; and a replenishment string connected between the well tool device and tool string. The replenishment string comprises pyrotechnic mixture. The elevating device is configured to control the movement of the replenishment string towards a heat generating process started by means of the ignition device.