Subsea Riser Tubular Sections With Local Vibration Damping
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Solution Overview
Problem
Subsea tubular systems face challenges in accurately predicting and managing vibrations caused by complex subsea currents, leading to increased stress and potential failure, as conventional methods often result in overbuilding with heavy materials that are still vulnerable to vibration-induced damage.
Innovation Solution
Incorporating vibration damping tubular sections made of materials like titanium or nickel alloys into subsea tubular systems, which alter the dynamic properties to reduce or eliminate resonant frequencies and alleviate loading stresses, allowing for the use of lighter and less costly conventional materials for the majority of the system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If heavy steel alloy tubulars are used throughout the entire length of the riser system, then the system can resist considerable stresses from subsea currents, but the system becomes excessively heavy and may still fail during periods of significant vibration
Solution Approach 1:
The patent applies different material properties to different sections of the riser system. Vibration damping sections made of materials with high damping capacity (such as titanium alloys or nickel alloys) are positioned at specific locations where vibration and resonant frequencies are most problematic, while other sections can use lighter conventional materials. This local differentiation allows the system to resist stresses where needed without the penalty of excessive weight throughout the entire system.
Solution Approach 2:
The riser system is constructed as a composite structure combining multiple materials with different properties. The system integrates conventional steel tubulars with vibration damping sections made of materials having superior vibration damping characteristics. This composite approach allows the system to leverage the strength of steel while incorporating the vibration damping properties of other materials, achieving both strength and reduced weight.
2Ease of manufacture
If conventional tubular materials are used throughout the system, then manufacturing is simpler and more consistent, but the system cannot effectively damp vibrations and may experience reduced lifespan due to vibration-induced stress
Solution Approach 1:
The patent implements local quality by incorporating vibration damping sections with specific material properties at strategic locations along the riser system. These sections are designed with materials having high damping capacity to specifically address vibration problems at those locations, while maintaining conventional materials in sections where vibration is less of an issue, thus preserving manufacturing simplicity where applicable.
Solution Approach 2:
The patent converts the harmful effect of vibrations into a beneficial outcome by using materials that naturally damp vibrations. The vibration damping sections are designed to absorb and dissipate vibrational energy, transforming the harmful mechanical vibrations into harmless thermal energy or other non-damaging forms, thereby extending the system's lifespan and reliability.
3Reliability
If the riser system is designed to accommodate unpredictable subsea currents and resonant frequencies, then the system may fail under extreme conditions, but using lighter materials throughout reduces cost and complexity
Solution Approach 1:
The patent changes the physical parameters of the riser system by incorporating sections with different material properties, specifically targeting vibration damping characteristics. By altering the material parameters in specific sections, the system can better withstand extreme conditions without requiring a complete redesign of the entire system, thus managing complexity while improving reliability.
Solution Approach 2:
The riser system is segmented into distinct sections with different material properties and functions. Vibration damping sections are separated from conventional sections, allowing each segment to be optimized for its specific function. This segmentation enables the system to handle extreme conditions effectively while keeping the overall design manageable by dividing it into smaller, more controllable units.
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 solution effectively reduces vibration-induced loading and stress, extending the lifespan of subsea tubular systems by altering their dynamic behavior, making them more resilient to unpredictable subsea currents and varying velocities.
Implementation Method 1
The second material has mechanical properties that damp vibration of the tubular system when subjected to underwater currents
Data Source
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AI summary
A subsea tubular system comprises extended sections of a first material and interposed sections of a second, different material that aids in damping vibration resulting from subsea dynamic conditions such as current. The vibration damping sections may make up a portion of the overall system significantly less than the sections of the first material. The number, length, and positions of the vibration damping sections may be selected based on factors such as the diameter, overall length, profile, and so forth. The system may be used as a riser or other conduit for the production of minerals such as oil and gas.