Subsea Winch System for Flexible Riser Connection
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Solution Overview
Problem
Existing methods for connecting and disconnecting flexible upper riser components to lower riser components in hybrid riser systems require diver intervention, which is unsafe and costly, especially at deep water depths where diving is not feasible.
Innovation Solution
A method utilizing a subsea winch system with remotely operated vehicles (ROVs) to securely connect and disconnect flexible upper riser parts to lower riser parts via a cable linkage, eliminating the need for diver intervention by using winching mechanisms and ROV-controlled operations to manage the riser connector and winch cables.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If diver intervention is used for connecting flexible upper riser parts to lower riser parts, then the connection operation can be performed, but it becomes unsafe and costly especially at deep water depths where diving is not feasible
Solution Approach 1:
The patent replaces the mechanical system of diver intervention with a remotely operated vehicle (ROV) system. The ROV is equipped with manipulators that can grasp and position the flexible riser part, and a winch system that can pay out and retrieve the riser. This substitution eliminates the need for human divers to work in hazardous deep water conditions while maintaining the ability to perform connection operations.
Solution Approach 2:
The patent introduces an intermediary system consisting of the ROV and winch mechanism between the operators on the surface and the riser connection operation. The winch cable acts as a mechanical intermediary to control the position of the flexible riser part, while the ROV serves as an intermediary vehicle that performs the actual manipulation and connection tasks remotely, allowing operators to control the operation from a safe distance.
2Ease of repair
If the entire riser string is recovered for replacement, then the flexible riser part can be replaced, but it increases operational costs and time
Solution Approach 1:
The patent divides the riser system into separable segments: the lower riser part remains in place on the seabed, while only the flexible upper riser part is detached, replaced, and reconnected. This segmentation allows for localized replacement of the flexible component without disturbing the entire riser string, significantly reducing replacement time and operational costs.
Solution Approach 2:
The patent enables the recovery and reuse of the lower riser part and other components that remain in place. Only the flexible upper riser part that has worn or damaged is discarded and replaced. This selective replacement approach recovers valuable components and reduces the need to recover and replace the entire riser string.
3Strength
If a rigid connection system is used, then structural strength is improved, but it reduces the flexibility needed to absorb vessel motion
Solution Approach 1:
The patent applies different quality characteristics to different parts of the riser system. The lower riser part and connection points maintain rigid, strong structural characteristics to ensure structural integrity and strength. The upper flexible riser part maintains flexible, adaptable characteristics to absorb vessel motion. This local differentiation of quality allows the system to simultaneously achieve both strength and flexibility where needed.
Solution Approach 2:
The patent incorporates dynamic characteristics into the riser connection system through the flexible upper riser part that can dynamically adjust to vessel motion. The flexible part acts as a dynamic element that absorbs and accommodates movements, while the lower rigid parts provide stable anchor points. This dynamic-fFlexible-rigid combination allows the system to maintain strength while adapting to changing conditions.
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
Enables safe and efficient connection and disconnection of flexible riser components at deep water depths without the need for divers, reducing operational costs and risks, and allowing for flexible riser replacement without recovering the entire string, thus extending the operational life of the riser system.
Implementation Method 1
operating a winching means on the upper riser assembly to wind in the cable linkage and draw the riser connector into a docking position on the upper riser assembly
Implementation Method 2
securing a cable linkage to the riser connector; operating a winching means on the upper riser assembly to wind in the cable linkage and draw the riser connector
Data Source
AI summary
A method is described for connecting a flexible upper riser part to a lower riser part via an upper riser assembly supporting a lower riser termination. The method includes securing a cable linkage to a riser connector at the lower end of the flexible upper riser part. The method includes operating a winching means on the upper riser assembly to wind in the cable linkage and draw the riser connector into a docking position on the upper riser assembly. Then coupling the riser connector to the lower riser termination occurs. A corresponding method of disconnecting the flexible riser part is also described, as well as a method of mounting the winching mechanism on a submerged landing platform.