Marine Riser Buoyancy Module Reaction Collar System
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Solution Overview
Problem
Existing subsea drilling systems face challenges in maintaining tension on heavy and long riser joints, which can lead to axial movement and potential damage during deployment, due to the susceptibility of thrust collars to disengagement from the riser joint.
Innovation Solution
The introduction of a reaction collar system that engages thrust collars to resist axial movement and secure the buoyancy module in place, using a mechanism that includes elastomeric materials and conical surfaces to enhance frictional forces and prevent disengagement, thereby stabilizing the riser joint during subsea operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If thrust collars are used to transfer axial buoyancy load, then the riser joint can be made neutrally buoyant, but the thrust collars are susceptible to disengagement causing axial movement and potential damage
Solution Approach 1:
The system divides the single thrust collar function into multiple components: thrust collars for load transfer and reaction collars for positional restraint. This segmentation allows each component to specialize in one aspect of the problem, with reaction collars preventing the disengagement issue while thrust collars maintain buoyancy function.
Solution Approach 2:
Reaction collars serve as intermediary elements between the thrust collars and the riser joint body. They mediate the positional control function, preventing axial movement of thrust collars without interfering with the thrust collars' primary function of transferring buoyancy loads.
2Length of moving object
If the riser joint is made longer and heavier to extend deeper, then production operations can occur in deeper waters, but the tension on the riser increases causing greater axial movement risk
Solution Approach 1:
Buoyancy modules provide upward buoyant force that counteracts the downward weight of extended riser joints in deep water applications. This reduces the net tension on the riser, thereby reducing axial movement forces on thrust collars and improving reliability.
Solution Approach 2:
Instead of trying to increase friction or mechanical locking to prevent thrust collar disengagement, the invention inverts the approach by using reaction collars to provide a mechanical stop that physically prevents axial movement in the problematic direction.
3Reliability
If frictional forces are increased to prevent thrust collar disengagement, then axial movement is reduced, but the complexity of the engagement mechanism increases
Solution Approach 1:
Conical surfaces are used in the reaction collar engagement mechanism. The conical geometry provides self-centering and automatic engagement features, reducing the need for complex adjustment mechanisms while ensuring reliable frictional contact and positional restraint.
Solution Approach 2:
The system uses elastomeric materials that can change their frictional properties based on compression and temperature. This material parameter change provides adaptive friction control, maintaining reliable engagement across varying operating conditions without requiring complex mechanical adjustment mechanisms.
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 reaction collar system effectively restricts axial movement of the buoyancy module and thrust collars, preventing damage to the riser joint and auxiliary lines, ensuring stable and secure deployment and operation of subsea drilling systems.
Implementation Method 1
using a mechanism that includes elastomeric materials and conical surfaces to enhance frictional forces and prevent disengagement
Implementation Method 2
a buoyancy module to make it close to neutrally buoyant when submerged underwater. The buoyancy module is coupled to the riser to increase its buoyancy
Data Source
AI summary
A marine riser system, a buoyancy system, and a method of buoying a body. A riser joint includes a body, a buoyancy module, a thrust collar, and a reaction collar. The buoyancy module is coupled around the body and configured to produce a buoyant force when submerged at a subsea location. The thrust collar is coupled around the body and engaged with the buoyancy module to transfer the buoyant force to the body. The reaction collar is engaged with the body such that movement of the buoyancy module is restricted by the reaction collar.