Subsea Gate Valve Slug Pit for Cuttings Management
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Solution Overview
Problem
Existing gate valve assemblies for subsea oil well control packages face issues with tubing conveyed strings cuttings obstructing or jamming the valve during the shut-down process, particularly due to the inability to handle cuttings of greater dimensions and the risk of damage from wireline cuttings dragging against the valve cavity.
Innovation Solution
A gate valve assembly with a slug pit in the valve block to contain cuttings from tubing conveyed strings, featuring a reciprocating cutting gate that transports cuttings to the slug pit during the closing motion, preventing obstruction and damage by ensuring they fall into a designated area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a recessed cutting edge is used to collect wireline cuttings, then the cutting operation can be performed, but the cuttings remain in the recess after the gate opens and may drag against the valve block causing damage
Solution Approach 1:
The invention extracts the cuttings from the valve cavity environment by providing a dedicated slug pit that receives and contains the cuttings separately from the main valve passage. The slug pit is positioned such that cuttings fall into it during gate closing and remain isolated during gate opening, preventing them from dragging against the valve block.
Solution Approach 2:
The slug pit acts as an intermediary structure between the cutting operation and the valve block. It provides a designated receptacle that mediates the interaction between cuttings and the valve cavity, allowing cuttings to be contained without contacting the valve block surfaces that would otherwise be damaged by dragging.
2Reliability
If the gate valve closes completely to seal the well, then emergency isolation is achieved, but cuttings may obstruct or jam the valve during reopening
Solution Approach 1:
The invention extracts cuttings from the potential obstruction zone by directing them into the slug pit during the closing operation. This separation ensures that when the gate opens for reopening operations, the cuttings remain isolated in the slug pit and cannot jam or obstruct the gate movement.
Solution Approach 2:
The slug pit is positioned and designed to receive cuttings during the closing motion before the gate reaches its fully closed position. This preliminary action of capturing cuttings prevents them from becoming obstacles during subsequent reopening operations.
3Adaptability or versatility
If double shear surfaces are used to cut tubing conveyed strings, then cutting capability is provided, but cuttings remain in the gate through hole and may fall into the well or obstruct the valve
Solution Approach 1:
The invention extracts cuttings from the gate through hole environment by providing a slug pit that receives them during the closing motion. This extraction prevents cuttings from remaining in positions where they could fall into the well or obstruct valve operations.
Solution Approach 2:
The slug pit is positioned in a different spatial dimension relative to the gate passage, allowing cuttings to be redirected from the linear passage into a lateral receptacle. This dimensional change in the cutting containment approach prevents cuttings from following the original path into the well or causing obstruction.
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 effectively prevents cuttings from obstructing the reopening of the valve and reduces the risk of damage to the valve cavity by containing cuttings within the slug pit, ensuring smooth operation and handling of cuttings of various dimensions.
Implementation Method 1
The gate valve assembly includes a reciprocating cutting gate that engages in a reciprocating motion in the valve cavity between an 'open' position and a 'closed' position. The reciprocating motion of the cutting gate valve transports one or more cuttings of the tubing conveyed strings to the slug pit.
Data Source
AI summary
A gate valve assembly (100) for use in subsea workover systems is disclosed. In an embodiment, the gate valve assembly (100) includes a valve block (102). The valve block (102) includes a cutting gate (204) disposed in a valve cavity (206) such that the cutting gate (204) can engage in a reciprocating motion in the valve cavity (206) between an “open” position and a “closed” position. The reciprocating motion of the cutting gate (204) results in a cutting operation of a tubing conveyed string passing through the gate valve assembly (100). The gate valve assembly (100) further includes a slug pit (202) formed in the valve block (102) alongside the valve cavity (206). The slug pit (202) defines an opening which can contain one or more cuttings from tubing conveyed springs resulting from the cutting operation. The reciprocating motion of the cutting gate (204) transports one or more cuttings of the tubing conveyed string to the slug pit (202).