Riser Stabilization Using Buoyancy Counterweights
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current systems for controlling risers in offshore hydrocarbon production are time-consuming, labor-intensive, and ineffective in managing lateral and vertical movements caused by vessel movement, currents, and changes in fluid density, leading to potential damage.
Innovation Solution
The implementation of a system that includes a positively buoyant member connected to the riser at one location and a negatively buoyant member at another, with the negatively buoyant member resting on the seabed, providing opposing forces to stabilize the riser and reduce movement, allowing it to return to an operational null position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If current systems are used to control riser movement, then the riser can be managed under normal conditions, but the system becomes time-consuming, labor-intensive, and ineffective under extreme conditions leading to potential damage
Solution Approach 1:
The patent applies counterweight principle by using a buoyancy system with positively and negatively buoyant members that create opposing forces to stabilize the riser. The positively buoyant member provides upward force while the negatively buoyant member (resting on seabed) provides downward anchoring force, creating a balanced system that resists lateral and vertical movements without requiring active intervention.
Solution Approach 2:
The riser stabilization system operates autonomously by utilizing the natural buoyancy forces of the positively and negatively buoyant members. The system self-regulates the riser position through the interaction of these buoyant forces with external disturbances (currents, vessel movement), eliminating the need for time-consuming manual interventions while maintaining reliability under extreme conditions.
2Strength
If the riser is stabilized using traditional methods, then some protection is provided, but the system remains vulnerable to severe or irreparable damage from extreme forces
Solution Approach 1:
The buoyancy system uses the counteracting forces between positively and negatively buoyant members to create a robust stabilization mechanism. This passive counterweight system provides continuous protection against lateral and vertical forces without adding complex active control mechanisms, thereby increasing damage resistance while maintaining relatively simple system architecture.
Solution Approach 2:
The system provides preemptive protection by pre-positioning the buoyant members to create stabilizing forces before extreme conditions occur. The negatively buoyant member is pre-anchored to the seabed and the positively buoyant member is pre-positioned along the riser, creating a cushioning effect that absorbs and distributes extreme forces before they can cause severe damage to the riser.
3Device complexity
If the riser is allowed to move freely, then the system remains simple, but the riser sustains deformation and severe damage
Solution Approach 1:
The buoyancy system introduces a passive counterweight mechanism using positively and negatively buoyant members that automatically counteract lateral and vertical movements. This adds minimal complexity to the system while effectively preventing riser deformation by creating restoring forces that oppose displacement from the vertical position.
Solution Approach 2:
The stabilization system operates autonomously without requiring external control mechanisms. The buoyant members self-adjust to provide stabilizing forces based on the riser's position and external forces acting upon it, preventing deformation through self-regulating buoyancy forces rather than complex active control systems.
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 solution effectively stabilizes the riser, reducing damage from external and internal forces, enabling the riser to withstand more extreme conditions and allowing for more efficient hydrocarbon production operations, including drilling and production, by maintaining the riser in a three-dimensional position that increases its length and flexibility.
Implementation Method 1
connecting a positively buoyant member to an elongated member at a first location
Implementation Method 2
connecting a negatively buoyant member to the elongated member at a second location, wherein at least a portion of the negatively buoyant member rests on a seabed
Data Source
AI summary
Systems and methods for controlling movement of an elongated member providing communication between a vessel and a subsea unit are provided. The method can include connecting a positively buoyant member to an elongated member at a first location and connecting a negatively buoyant member to the elongated member at a second location, wherein at least a portion of the negatively buoyant member rests on a seabed when the elongated member is in an operational null position.