Angled Wing Bore Self-Draining Subsea Production Tree
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Solution Overview
Problem
In subsea oil and gas production, hydrate formation in equipment poses challenges due to low temperatures and high pressures, leading to flow restrictions and increased complexity in management, especially during shut-in operations where inhibitors cannot be injected in time to prevent hydrate formation.
Innovation Solution
A production assembly design featuring a production tree with angled wing bores that facilitate fluid drainage and the introduction of chemical inhibitors to prevent hydrate formation, allowing for self-draining and reduced need for insulation, even in complex subsea environments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If production equipment is insulated to prevent hydrate formation, then hydrate formation is suppressed, but the process becomes expensive, difficult, and time-consuming
Solution Approach 1:
The patent extracts the fluid drainage function from the production equipment by providing separate drainage pathways that lead hydrates away from critical equipment areas. This eliminates the need for complex insulation applications while still preventing hydrate-related problems through physical removal of hydrate-forming fluids.
Solution Approach 2:
The patent introduces drainage pathways as an intermediary mechanism between the production equipment and the external environment. These pathways serve as a mediator that allows controlled removal of hydrate-prone fluids without requiring direct insulation of the equipment, thus simplifying the overall system.
2Reliability
If production is shut-in to manage emergencies, then safety is improved, but hydrate formation risk increases due to cooling and inability to inject inhibitors in time
Solution Approach 1:
The patent implements preliminary drainage pathways that are pre-configured to actively remove fluids before hydrates can form during shut-in conditions. This preliminary action occurs automatically without requiring inhibitor injection, thus maintaining safety benefits while preventing hydrate formation risk.
Solution Approach 2:
The drainage system operates autonomously during shut-in conditions, self-regulating fluid removal without requiring external intervention or inhibitor injection. This self-service mechanism ensures continuous protection against hydrate formation while maintaining the safety benefits of shut-in operations.
3Reliability
If inhibitor injection is used to prevent hydrate formation, then hydrate suppression is achieved, but response time is insufficient during emergencies
Solution Approach 1:
The patent extracts the time-consuming inhibitor injection process by replacing it with passive drainage pathways that continuously remove hydrate-prone fluids. This eliminates the response time delay associated with inhibitor injection while maintaining effective hydrate suppression.
Solution Approach 2:
The patent replaces the active mechanical injection system with a passive gravitational or pressure-driven drainage system. This substitution eliminates the need for rapid response injection operations, allowing continuous hydrate prevention without time loss.
4Ease of repair
If manual re-entry and connection areas are kept accessible, then maintenance capability is improved, but insulation coverage is reduced
Solution Approach 1:
The patent extracts the protection function from the inaccessible areas by providing drainage pathways that remove hydrate risks from areas that must remain accessible for maintenance. This allows full maintenance access while still preventing hydrate formation through active fluid removal.
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 angled wing bore design and inhibitor injection effectively prevent hydrate formation, ensuring continuous fluid flow and reducing the risk of equipment blockage during shut-in operations, thereby enhancing the efficiency and reliability of subsea production equipment.
Implementation Method 1
A production assembly design featuring a production tree with angled wing bores that facilitate fluid drainage
Implementation Method 2
Gas hydrates may be thermodynamically suppressed by adding materials such as salts or glycols, which operate as 'antifreeze.' Commonly, methanol or methyl ethylene glycol (MEG) may be injected at the subsea tree as the antifreeze material.
Data Source
AI summary
A production assembly includes a tree body, in which the tree body includes a main production bore formed about an axis and a wing bore extending through the tree body from the main production bore. The tree body may further include a wing valve in fluid communication with the wing bore to control the flow of fluid through the wing bore, in which at least a portion of the wing bore is angled from perpendicular with respect to the axis of the main production bore.