Downhole Blanking Plate Welding With Exothermic Powder
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Solution Overview
Problem
Conventional methods for abandoning oil wells are time-consuming, costly, and environmentally impactful due to the need for excavation and external cutting, and traditional arc welding cannot be performed downhole, making it difficult to achieve a quality weld using wire fed welding.
Innovation Solution
A downhole welding tool with a tubular body and welding head assembly that delivers and welds a blanking plate to the wellbore casing using exothermic welding powder, eliminating the need for excavation by fitting within the casing and allowing for internal welding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If wire fed welding is used downhole, then welding can be performed internally without excavation, but the process becomes highly sensitive to impurities and requires extensive cleaning
Solution Approach 1:
The patent replaces wire fed arc welding with exothermic powder welding. Instead of using a mechanical wire feeding system with arc discharge, the invention uses a chemical exothermic reaction between aluminum powder and iron oxide powder to generate molten metal for welding. This substitution eliminates the sensitivity to impurities and cleaning requirements associated with wire fed welding while enabling downhole welding capability.
Solution Approach 2:
The patent changes the welding process parameters from low-temperature arc welding to high-temperature exothermic welding. The exothermic reaction generates temperatures sufficient to melt steel and create strong welds directly in the downhole environment without requiring the precise control and clean conditions needed for wire fed welding.
2Ease of manufacture
If traditional arc welding equipment is used, then welding can be performed externally, but excavation is required and the process becomes time-consuming and costly
Solution Approach 1:
The patent nests the welding tool and exothermic welding materials within the existing wellbore casing. The tubular body of the welding tool fits inside the casing, and the welding head assembly with powder containers is inserted through the casing. This nesting approach eliminates the need for excavation to access the casing for welding operations, allowing the entire process to be completed from the surface.
Solution Approach 2:
The patent extracts the welding capability from surface-based arc welding equipment and creates a self-contained exothermic welding system. The exothermic welding powder and ignition system are packaged in portable containers that can be delivered downhole, separating the welding function from the need for external excavation and surface equipment.
3Ease of manufacture
If a compact welding tool is used to fit downhole, then excavation is avoided, but the welding equipment size is constrained
Solution Approach 1:
The patent segments the welding tool into modular components: a tubular body for structural support and depth control, a welding head assembly containing the connector device and powder containers, and separate powder containers that can be independently handled. This segmentation allows each component to be optimized for its specific function while fitting within the constrained downhole environment.
Solution Approach 2:
The tubular body serves multiple functions: it provides structural support for the welding head assembly, acts as a depth control mechanism through friction against the casing, and serves as a conduit for delivering the welding tool downhole. The welding head assembly integrates both the connector device for retaining the well component and the powder container system, combining multiple functions in a single compact unit.
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 efficient and cost-effective sealing of wellbore casings by avoiding excavation and providing a reliable weld quality without the sensitivity issues of wire fed welding, reducing environmental impact and operational complexity.
Implementation Method 1
The chamber has at least a portion extending adjacent the well component to be retained and proximate the downhole surface to which the well component is to be welded when the welding tool is positioned downhole in the wellbore casing
Data Source
AI summary
A welding tool for welding a blanking plate within a wellbore casing downhole thereby sealing the wellbore is described. The tool comprises a tubular body of a diameter sufficiently narrow to fit in a wellbore casing, the tubular body having a downhole end and a surface end; and a welding head assembly connected to the downhole end of the tubular body. The welding head assembly comprises a connector device for retaining a blanking plate to be welded within the wellbore casing, and a welding powder container which comprises a chamber for holding the exothermic welding powder, the chamber having at least a portion extending adjacent the blanking plate to be retained and proximate the wellbore casing to which the blanking plate is to be welded when the tool is positioned downhole in the wellbore casing; and an igniter wire opening for accommodating an igniter wire extending into the chamber.