Wellbore Casing Slotting via Rotating Jet Erosion

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Solution Overview

Problem

Existing wellbore casing slotting tools lack efficiency, flexibility, reliability, and maintainability, particularly in forming slots without severing the casing and ensuring effective cement flow for well plugging and abandonment.

Innovation Solution

A cutting tool with a jetting assembly and indexing assembly, where the outer shell engages with a helical groove on the mandrel, allowing axial movement of the outer shell while the inner mandrel and jetting assembly remain stationary, enabling rotation and slot formation with jetting fluid, and allowing for selective nozzle activation and use of a solid base to stop movement, facilitating cement flow into the wellbore.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If weight is applied to the mandrel to slide it axially downwards to cut slots with jets, then slots are formed in the casing, but the casing may be completely severed into distinct portions

Engineering Contradiction:

Improveslot formation efficiencyVSAvoidcasing structural integrity

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

Instead of applying weight to slide the mandrel axially downwards to cut slots (conventional approach), the invention applies axial force to the outer shell to rotate the indexing assembly while the jetting assembly remains axially stationary. This inversion of the cutting mechanism prevents casing severing while still forming slots effectively.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The invention replaces the mechanical sliding cutting system with a rotational jetting system. The jetting assembly rotates within the indexing assembly to form slots, eliminating the need for axial sliding that causes casing severing. This substitution maintains slot formation capability while preserving casing integrity.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Ease of manufacture

If a jetting assembly is made movable axially to cut slots, then slotting can be performed, but the device complexity increases with additional components like slips and mandrels

Engineering Contradiction:

Improveslotting capabilityVSAvoidtool assembly structure

Core Design Contradiction:

Ease of manufactureVSDevice complexity

Solution Approach 1:

The tool is divided into functionally independent segments: the indexing assembly (outer shell with helical groove) and the jetting assembly (nozzles on mandrel). This segmentation allows each component to perform its specific function independently, simplifying the overall design while maintaining slotting capability.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The indexing assembly serves multiple functions: it provides structural support, enables rotation of the jetting assembly, and controls the slotting operation. The jetting assembly simultaneously performs cutting and can be rotated to form multiple slots, reducing the need for separate components.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Productivity

If the cutting tool is disposed via conveyance and weight is applied for axial movement, then slotting operation can be performed, but the ease of operation is reduced due to complex deployment and activation procedures

Engineering Contradiction:

Improveslot formation capabilityVSAvoidtool deployment complexity

Core Design Contradiction:

ProductivityVSEase of operation

Solution Approach 1:

The indexing assembly automatically converts the axial force applied to the outer shell into rotational motion of the jetting assembly through the helical groove mechanism. This self-converting mechanism eliminates the need for complex deployment procedures and manual activation, improving ease of operation.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The tool transitions from a static deployment state to a dynamic operating state through the application of axial force, which automatically triggers rotation and slotting. This dynamic response simplifies operation by eliminating manual intervention steps while maintaining productive slot formation capability.

Inventive Principle:

Principle #15Dynamics

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 solution enhances the efficiency and reliability of slot formation in wellbore casings, allowing for precise slot patterns and effective cement sealing without severing the casing, improving the wellbore plugging and abandonment process.

Implementation Method 1

flowing a jetting fluid through the jetting assembly while the jetting assembly is rotated, such that the jetting assembly forms slots in the casing

Methodology Applied

Scientific EffectJet erosion: Jet Erosion

Data Source

PatentEP2561172B1Method for forming slots in a wellbore casing

Publication Date: 2020.02.12 SERVICES PETROLIERS SCHLUMBERGER SA

Figure 1A~1B
Figure 2A~3
Figure 4A~5A

AI summary

An embodiment of a method for forming slots in a wellbore casing, comprises providing at least one cutting tool, the cutting tool comprising at least a jetting assembly and an indexing assembly, disposing the cutting tool into the wellbore via a conveyance, stopping movement along the wellbore axis of the cutting tool, and forming slots in the casing by actuating the indexing assembly such that the jetting assembly forms slots in a predetermined pattern in the casing. In an embodiment, the method further comprises flowing a material into the slots formed in the casing to seal the wellbore.