Downhole Propellant Jet Tool for Rapid Casing and Cement Removal

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Solution Overview

Problem

Conventional methods for removing casing and cement in well abandonment operations are slow and costly, as they rely on milling or hydro-abrasive cutters, and perforating charges create small holes rather than large openings.

Innovation Solution

A tool utilizing a propellant source with a low rate of combustion that deflagrates to produce a combustion jet, which is directed through nozzles to manipulate tubular materials via ablation, cutting, displacement, heating, abrasion, or erosion, facilitated by modifying agents and controlled by an opening mechanism.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If milling tools or hydro-abrasive cutters are used to remove casing and cement, then the removal process is gradual and controlled, but the operation becomes very slow and expensive

Engineering Contradiction:
Improvecontrolled removalVSAvoidoperation speed
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The patent replaces mechanical milling tools and hydro-abrasive cutters with a chemical reaction system. A propellant charge reacts with the casing and cement through chemical combustion, rapidly removing material through controlled explosion rather than gradual mechanical or hydraulic erosion. This substitution of chemical reaction for mechanical removal achieves both speed and control.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the fundamental parameter of material removal from mechanical force to chemical reaction energy. By using a propellant charge that undergoes rapid combustion, the system transforms the removal mechanism from slow mechanical wear to fast chemical decomposition and erosion, dramatically increasing productivity while maintaining precision through controlled charge placement and composition.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If perforating charges are used to penetrate casing, then fluid communication is achieved, but only small holes are produced rather than large openings

Engineering Contradiction:
Improvefluid communicationVSAvoidopening size
Core Design Contradiction:
ReliabilityVSArea of stationary object

Solution Approach 1:

The patent applies excessive action by using a propellant charge designed to create significantly larger openings than traditional perforating charges. Instead of merely creating small holes for fluid communication, the chemical reaction produces large-diameter openings that exceed the minimum requirement, thereby simultaneously achieving reliable fluid communication and large opening size.

Inventive Principle:
Principle #16Partial or excessive action

3Ease of operation

If conventional milling or cutting methods are used to remove tubulars, then precise control over the removal process is maintained, but the process becomes time-consuming and costly

Engineering Contradiction:
Improveprocess controlVSAvoidoperation duration
Core Design Contradiction:
Ease of operationVSLoss of time

Solution Approach 1:

The patent replaces the mechanical control system with a chemical control system. Instead of mechanically guiding a milling tool through precise movements, the system uses controlled chemical reactions of a propellant charge to remove material. The control is maintained through precise placement, composition, and timing of the chemical reaction rather than mechanical guidance, dramatically reducing operation time while preserving control.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent employs preliminary action by pre-positioning the propellant charge against the tubular or cement before activation. The charge is prepared and placed in the exact location needed, with all control parameters predetermined in the charge design itself. When activated, the pre-positioned charge executes the removal action instantly, eliminating the time-consuming step-by-step mechanical removal process while maintaining precision through the preliminary setup.

Inventive Principle:
Principle #10Preliminary action

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 method significantly reduces time and costs by efficiently removing or altering tubular materials, allowing for faster well abandonment procedures.

Implementation Method 1

at least one propellant source located within the chamber, wherein propellant of the propellant source is an explosive material having a low rate of combustion that once ignited deflagrates to produce propellant gas and other combustion products

Methodology Applied
Scientific EffectDeflagration: Deflagration

Implementation Method 2

at least one of the propellant sources is configured to combust upon ignition to deflagrate and release a combustion jet

Methodology Applied
Scientific EffectCombustion: Combustion

Implementation Method 3

The stream of combustion products may erode, ablate, abrade or remove at least a portion of the tubular to be manipulated

Methodology Applied
Scientific EffectAblation: Ablation

Implementation Method 4

The stream of combustion products may erode, ablate, abrade or remove at least a portion of the tubular to be manipulated

Methodology Applied
Scientific EffectErosion: Erosion

Implementation Method 5

the chamber includes an opening mechanism configured to prevent fluid communication between the chamber and the/each nozzle inlet until pressure in the chamber reaches a threshold pressure, higher than the environmental pressure

Methodology Applied
Scientific EffectPressure threshold control:

Data Source

PatentEP3869002B1Downhole tool with a propellant charge
Publication Date: 2026.01.28 SPEX CORP HLDG LTD
  • EP3869002B1 patent drawingFigure 1~2
  • EP3869002B1 patent drawingFigure 3~4
  • EP3869002B1 patent drawingFigure 5~6

AI summary

A tool (10) for manipulating a material includes a body defining a chamber (22) and at least one propellant source (26) located within the chamber (22). At least one nozzle (24) having an inlet and an outlet, is in selective fluid communication with the chamber (22). At least one mechanism (38) is provided for igniting the/each propellant source, creating a combustion zone (42) on the propellant source (26). At least one of the propellant sources (26) is configured to combust upon ignition to deflagrate and release a combustion jet. The chamber (22) includes an opening mechanism configured to prevent fluid communication between the chamber and the/each nozzle inlet until pressure in the chamber reaches a threshold pressure, higher than the environmental pressure, whereupon the combustion jet flows into the/each nozzle inlet, the combustion jet then flowing out of the tool through the/each nozzle outlet towards, and into engagement with, a material to be manipulated.