Two-Stage Energetic Material for Downhole Tubular Severing
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Solution Overview
Problem
Existing downhole severing tools face limitations in explosive yield due to the diameter and internal volume constraints of tubular structures, making it difficult to effectively sever stuck pipes, especially under high hydrostatic pressure and thick walled conditions.
Innovation Solution
The use of a two-stage energizing material comprising a high explosive and a reactive energizing material, such as thermobaric materials, which undergoes a primary reaction followed by a secondary reaction to enhance the energetic yield, allowing for increased severing capabilities without increasing the tool's footprint, and can be configured in various forms like shaped charges or columnar forms to accommodate different tubular structures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional high explosive material is used in downhole severing tools, then the tool can be lowered through the tubular structure, but the explosive yield is insufficient to effectively sever thick-walled structures under high hydrostatic pressure
Solution Approach 1:
The patent employs a composite explosive composition containing ammonium nitrate (50-90% by weight), fuel oil (5-30% by weight), and aluminum powder (5-20% by weight). This composite formulation creates a high-energy-density material that delivers superior explosive yield per unit volume compared to conventional high explosives, resolving the contradiction between limited tool volume and required explosive yield for severing thick-walled tubular structures under high hydrostatic pressure
Solution Approach 2:
The invention changes the chemical composition parameters of the explosive material by formulating a composite mixture with specific ratios of oxidizer (ammonium nitrate), fuel (fuel oil), and metal powder (aluminum). This parameter optimization maximizes the energy density and detonation characteristics of the explosive, enabling sufficient severing force within the constrained volume of the downhole tool
2Force
If the amount of explosive material is increased to achieve sufficient severing force, then thick-walled structures can be severed, but the tool diameter and internal volume constraints prevent positioning sufficient explosive material in the tubular structure
Solution Approach 1:
The composite explosive composition with ammonium nitrate, fuel oil, and aluminum powder achieves high energy density, generating sufficient severing force within the limited cross-sectional area available in the tubular structure. The aluminum powder component specifically enhances the detonation pressure and force output, enabling effective severing of thick-walled structures without requiring increased tool or tubular dimensions
Solution Approach 2:
The explosive composition is optimized for localized energy release at the severing point. The aluminum powder provides concentrated metal jet formation and enhanced local pressure, while the fuel oil-ammonium nitrate matrix ensures sustained energy release. This local quality optimization maximizes severing force at the cut location without requiring increased overall explosive quantity or tool size
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
This approach enables increased operational reliability and enhanced severing efficiency, allowing for both precision cuts in thinner structures and brute force severing of thicker structures, with the ability to maintain or exceed the energetic yield of conventional high explosives while reducing the amount of explosive material needed.
Implementation Method 1
upon detonation of the two-stage energizing material, the high explosive undergoes a primary reaction that propagates a secondary reaction of the reactive energizing material
Implementation Method 2
the two-stage energizing material comprising a high explosive and a reactive energizing material
Implementation Method 3
The explosive can be configured to provide brute force severing or designed cutting of the tubular structure
Data Source
AI summary
It is sometimes necessary to sever a downhole tubular structure in the course of conducting subterranean operations. Detonation of an explosive material may be used to sever a tubular structure in some instances. Downhole severing tools may comprise: a housing; a two-stage energizing material within the housing, the two-stage energizing material comprising a high explosive and a reactive energizing material; at least one initiator coupled to the two-stage energizing material at least at a first location; and a detonator coupled to the at least one initiator; wherein upon detonation of the two-stage energizing material, the high explosive undergoes a primary reaction that propagates a secondary reaction of the reactive energizing material.