Compact Subsea Cutting System for Drill Pipe
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Solution Overview
Problem
Bulky and heavy Blowout Preventer (BOP) stacks are costly and inefficient for offshore operations, requiring significant maintenance and limiting the number of wells that can be economically reworked, especially when cutting pipe, as they are prone to getting stuck and require heavy lifting equipment.
Innovation Solution
A compact cutting system with a housing defining a throughbore and two movable gates, which are operable for cutting drill pipe, coiled tubing, and wireline, designed to be lightweight and substitute for a BOP, utilizing a gate valve for sealing and requiring less hydraulic fluid and stroke length, allowing for efficient cutting without sealing the throughbore.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a BOP stack is used for cutting pipe, then cutting capability is achieved, but weight and bulk increase significantly
Solution Approach 1:
The BOP stack is segmented into separate functional components: a gate valve for sealing and a独立的 cutting system with two gates and cutters. This allows the cutting function to be performed by a lighter, dedicated device rather than the entire heavy BOP stack, resolving the contradiction between cutting capability and weight.
Solution Approach 2:
The gate valve is designed with multi-functionality, serving both as a sealing device and as a mounting structure for the cutting system. This universal design allows the same component to provide both sealing and cutting capabilities, reducing overall system weight while maintaining both functions.
2Adaptability or versatility
If a BOP stack is used for cutting pipe, then cutting function is provided, but device complexity and maintenance requirements increase
Solution Approach 1:
By separating the cutting function into a dedicated device with two gates and cutters, the system reduces overall complexity. Each component has a specific function, making the system easier to understand, operate, and maintain compared to a monolithic BOP stack that must perform multiple functions.
Solution Approach 2:
The cutting gates and cutters are designed as replaceable, relatively simple components that can be easily replaced after use or when worn. This approach reduces maintenance complexity and costs compared to maintaining the entire BOP stack, as only the simple cutting components need replacement rather than the complex sealing system.
3Adaptability or versatility
If a BOP stack is used for cutting pipe, then cutting capability is achieved, but installation and removal costs increase due to heavy lifting equipment requirements
Solution Approach 1:
The segmentation of the BOP stack into a gate valve and a separate, lighter cutting device dramatically reduces installation and removal costs. The cutting device can be installed and removed without requiring heavy lifting equipment, as it is significantly lighter than the traditional BOP stack, while still providing the necessary cutting capability.
4Adaptability or versatility
If a BOP stack is used for cutting pipe, then cutting function is provided, but the cut pipe may become stuck blocking other operations
Solution Approach 1:
The cutting gates are designed to fully open and remove from the throughbore after cutting, extracting the cut pipe completely from the device. This prevents the cut pipe from becoming stuck and blocking other operations, as the gates clear the throughbore entirely rather than leaving pipe segments trapped within the BOP stack.
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 compact cutting system effectively cuts drill pipe and tubing while being significantly lighter than traditional BOPs, reducing maintenance costs and enabling more wells to be reworked economically, with the ability to cut up to 4½ inch drill pipe and 16.60 lb/ft coiled tubing without leaving residues.
Implementation Method 1
a piston and a piston rod operably connected to the gate with a stroke length less than a diameter of the throughbore
Data Source
AI summary
As compared to a BOP, a compact lightweight cutting system may have two gates with cutters moveable in opposite directions to cut drill pipe. The system utilizes a relatively short stroke and relatively less hydraulic oil for subsea operation. The system utilizes two gates with flat surfaces for sealing with the two corresponding upper and lower seats. The compact cutting system with a gate valve can be used to substitute for a BOP to significantly reduce the size and weight required in an intervention system.