Downhole Disconnect Tool Using Abrasive Slurry Parting
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Solution Overview
Problem
Existing downhole disconnect tools are inadequate for efficiently separating stuck sections of tubular strings in subterranean wells, as they often require complex and costly operations to retrieve stuck components.
Innovation Solution
A disconnect tool system that uses an abrasive slurry to erode through a reduced cross-section area of the tubular string, allowing for mechanical separation of stuck components by increasing the flow velocity of the slurry through nozzles or vanes, enabling efficient retrieval of stuck sections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If traditional mechanical disconnect tools are used to separate stuck tubular sections, then the separation capability is limited, but the operational complexity and cost increase significantly
Solution Approach 1:
The patent replaces traditional mechanical disconnect mechanisms with an abrasive slurry erosion system. High-velocity abrasive slurry is directed through nozzles at the tubular wall to erode and create a parting point, eliminating complex mechanical cutting or shearing mechanisms and simplifying the overall system operation
Solution Approach 2:
The invention uses hydraulic pressure to propel abrasive slurry through the tubular and out through nozzles at high velocity. The slurry is pumped downhole and directed against the tubular wall to erode through the material, using fluid dynamics rather than mechanical contact to achieve separation
2Productivity
If abrasive slurry is used to erode through the tubular string, then the separation efficiency improves, but the risk of tubular damage increases
Solution Approach 1:
The abrasive slurry is directed through nozzles positioned at specific locations to concentrate erosion at a targeted point on the tubular wall. This localized approach allows controlled creation of a parting point without subjecting the entire tubular to abrasive damage, maintaining structural integrity in non-target areas
Solution Approach 2:
The system first erodes through the tubular wall to create a controlled parting point before any separation force is applied. This preliminary erosion creates a weak point that guides where the separation will occur, ensuring clean separation at the desired location rather than unpredictable failure points
3Loss of time
If high flow velocity is achieved through nozzles to increase erosion rate, then the separation time is reduced, but the erosive force on the tubular increases
Solution Approach 1:
High-velocity slurry is concentrated through nozzles at specific erosion points rather than being distributed uniformly. This focuses the erosive force locally to achieve rapid penetration at the target point while minimizing overall exposure of the tubular to high-velocity abrasive flow, reducing total erosive damage
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 system effectively separates stuck tubular string components by using abrasive wear to part the tubulars, facilitating the retrieval of the upper portion while leaving the lower portion for later retrieval, thus improving operational efficiency and reducing costs.
Implementation Method 1
uses an abrasive slurry to erode through a reduced cross-section area of the tubular string
Implementation Method 2
increasing the flow velocity of the slurry through nozzles or vanes
Data Source
AI summary
A system can include a disconnect tool connected as part of a tubular string, the disconnect tool including an outer housing, and an inner mandrel in the outer housing, in which an abrasive slurry is directed to flow through the tubular string and from the inner mandrel to an annulus between the inner mandrel and the outer housing, and the abrasive slurry erodes through the outer housing. A method can include installing a tubular string in a well, then deploying a disconnect assembly into the tubular string, and flowing an abrasive slurry through the disconnect assembly, thereby parting the tubular string. A disconnect tool can include a rotational flow structure configured to induce rotational flow, and an inner diameter decrease downstream of the rotational flow structure.