Abrasive Cutting Fluid Laminar Flow Conduit Wear
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Solution Overview
Problem
Existing methods for severing subsea wellheads using abrasive cutting fluids face challenges such as high abrasive wear in pipes, inefficient cutting due to energy loss in water jets, and increased time and cost associated with frequent pipe replacements.
Innovation Solution
A method involving a pre-mix of abrasive particles, water, and a high concentration of flocculent thickener is formed and entrained in a carrier fluid to promote laminar flow, reducing wear on conduits and enhancing cutting efficiency by maintaining abrasive particles in suspension and aligning fluid flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If very abrasive grit is used to cut efficiently, then cutting performance is improved, but wear in the conduit conveying the cutting medium increases
Solution Approach 1:
A carrier fluid is introduced as an intermediary between the abrasive grit and the conduit walls. The carrier fluid suspends the abrasive particles and directs them along the central axis of the conduit, creating a protective buffer that prevents direct contact between the abrasive grit and the conduit interior surfaces, thereby reducing wear while maintaining cutting efficiency
Solution Approach 2:
The flow regime parameter is changed from turbulent to laminar flow by controlling the velocity profile and using the carrier fluid's viscous properties. This parameter change causes abrasive particles to follow streamlined paths along the conduit centerline rather than randomly impacting the walls, significantly reducing abrasive wear while preserving the cutting capability of the grit
2Speed
If high pressure water jet is used for cutting, then cutting speed is improved, but energy loss to surrounding water increases
Solution Approach 1:
The cutting medium is segmented into discrete abrasive particles suspended in a carrier fluid rather than a continuous water jet. This segmentation allows the abrasive particles to maintain their kinetic energy and cutting effectiveness while the carrier fluid provides a controlled flow path that reduces energy dissipation to the surrounding water environment
3Reliability
If pipe work is renewed frequently due to wear, then cutting operation continuity is maintained, but downtime and operational costs increase
Solution Approach 1:
The carrier fluid acts as a protective intermediary that extends the service life of the conduit by preventing direct abrasive contact with the conduit walls. This extension of conduit lifespan reduces the frequency of replacements and minimizes downtime for maintenance operations
Solution Approach 2:
The carrier fluid is pre-introduced into the conduit system before abrasive grit is fed. This preliminary action establishes a protective flow environment that prevents wear from occurring in the first place, rather than attempting to mitigate wear after damage has begun
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 approach reduces conduit wear, decreases downtime, and improves cutting performance by maintaining laminar flow and energy efficiency, allowing for more effective and efficient cutting operations.
Implementation Method 1
the thickener may be present in sufficient concentration in one or both of the pre-mix and carrier fluid to act as a viscosity modifier, for example, to promote laminar flow of the cutting fluid through the conduit
Implementation Method 2
the thickener may be present in sufficient concentration in one or both of the pre-mix and carrier fluid to act as a viscosity modifier
Implementation Method 3
The thickener may preferably include one or more flocculent and/or suspension agents
Implementation Method 4
the thickener may be present in sufficient concentration in one or both of the pre-mix and carrier fluid to act as a viscosity modifier
Data Source
Figure 1~2
Figure 3~5
Figure 6~8
AI summary
To form an abrasive cutting fluid, two sizesof abrasive grit are mixed together with a high concentration of flocculent and water to form a thick slurry which is fed by a pump (3) into a pressure vessel (4). Water from feed point (7) passes through a flocculent retention chamber (8) and flocculent is added at high dosage. The flocculated water is fed by pump (6) through manifold (13) and slurry from pressure vessel (4) is added to establish a laminar flow through flexible hose (14) which leads to a nozzle (11). The fluid exits the nozzle (11) as a high-pressure, abrasive cutting jet. The laminar flow may reduce internal wear in the flexible hose (14).