Riserless Subsea Well Intervention System
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Solution Overview
Problem
Conventional subsea well intervention systems require a riser, which is expensive and poses challenges due to the complexity and weight of multiple components, leading to reliability and maintenance issues, especially in remote subsea locations.
Innovation Solution
A riserless subsea well intervention system with a surface injector and a subsea snubbing jack, utilizing a subsea hydraulic power unit and electric umbilical for dynamic control, featuring traveling slips and hydraulic actuation, reducing the need for a subsea injector and minimizing power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a riser is used in conventional subsea well intervention systems, then the system can provide stable support and control, but the system becomes expensive and complex with multiple components that reduce reliability and increase maintenance difficulty
Solution Approach 1:
The patent removes the riser from the subsea well intervention system, extracting this complex component entirely. The system now uses a surface injector on a vessel that directly deploys tubing to the subsea well without requiring a riser structure, thereby reducing system complexity and component count while maintaining operational capability
Solution Approach 2:
The surface injector on the vessel performs multiple functions: it serves as both the deployment mechanism for tubing and the control platform for subsea operations. This multi-functional approach eliminates the need for separate riser structures and associated heave compensation devices, reducing overall system complexity
2Force
If a subsea injector is used to insert tubular members, then the insertion force can be provided directly at the subsea location, but the power consumption increases and the number of components increases
Solution Approach 1:
The patent removes the subsea injector component entirely from the system. Instead of providing insertion force directly at the subsea location, the system uses a surface injector that delivers tubing to the well, eliminating the need for a powered subsea injection mechanism and its associated power consumption
Solution Approach 2:
The patent introduces an intermediary approach where the surface injector serves as the primary force-providing mechanism, and the subsea wellhead assembly acts as the intermediary point for tubing insertion. This eliminates the need for a powered subsea injector while still achieving effective tubular member insertion
3Adaptability or versatility
If multiple components are used in the subsea well intervention system, then the system can perform complex functions, but the maintenance and repair accessibility is reduced in remote subsea locations
Solution Approach 1:
The patent segments the well intervention system into distinct functional modules: a surface injector on the vessel for tubing deployment, a subsea wellhead assembly for tubing reception and well control, and the subsea well itself. This modular segmentation allows each component to be independently maintained or replaced, improving accessibility for repairs in remote locations
Solution Approach 2:
By removing the riser and subsea injector components, the patent reduces the number of parts that require maintenance in hard-to-reach subsea locations. The simplified system has fewer components that need servicing, thereby improving overall maintenance accessibility
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
This system enables efficient and reliable insertion and extraction of tubular members with fewer components, reduced power requirements, and improved accessibility for maintenance, while being responsive to varying well conditions without the need for a riser or subsea injector.
Implementation Method 1
a hydraulic actuation means for movement of the traveling slip bowl relative to the stationary slip bowl
Implementation Method 2
a heave compensation means for maintaining tension of the tubular member between the surface injector and the snubbing jack
Implementation Method 3
A subsea hydraulic power unit is in fluid connection to the snubbing jack
Data Source
AI summary
The system for inserting a tubular member from a surface into a subsea well includes a riserless vessel, a surface injector being mounted on the vessel at the surface and delivering tubular member, such as coiled tubing, to the subsea well from the surface, a subsea snubbing jack releasably engaged to the tubular member, a subsea hydraulic power unit connected to the snubbing jack, and a device to maintain tension of the tubular member between the surface injector and the snubbing jack. The dynamic control of the subsea snubbing jack provides either active additional force for pipe light and pipe heavy conditions or passive support of the tubular member for equilibrium conditions without a riser. The method is responsive to transitions between well conditions. A riserless system without a subsea injector can more efficiently and reliably insert coiled tubing under various well conditions and during changes in the well conditions.