High Pressure Swivel Multi Seal Pressure Regulation
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Solution Overview
Problem
High-pressure swivels used in offshore floating production face challenges in sealing fluids at elevated pressures and temperatures, exceeding the limits of existing sealing materials, leading to issues with gas migration and seal degradation.
Innovation Solution
A high-pressure swivel design incorporating a first and second pressure control unit to regulate pressure across multiple seals, maintaining constant pressure in the isolation and primary gap sections, and using a dynamic isolation system to prevent gas migration and extend seal lifetime by managing differential pressures and contaminants.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If existing sealing materials are used in high-pressure swivels, then the swivel can operate at standard pressures (100-400 bar), but the seals fail when pressure and temperature exceed certain limits due to gas migration and seal degradation
Solution Approach 1:
The sealing system is divided into multiple independent seal stages (first seal, second seal, third seal) arranged in series. Each seal operates at a controlled pressure differential, with pressure control units regulating the pressure between seals. This segmentation allows the system to handle high temperatures and pressures by distributing the sealing burden across multiple reliable stages rather than relying on a single seal to withstand all conditions.
Solution Approach 2:
The invention changes the pressure parameter distribution across the sealing system by introducing active pressure control units that regulate the pressure between seals. Instead of allowing uniform high pressure across all seals, the system maintains specific pressure differentials at each seal stage, enabling reliable operation at temperatures and pressures that would otherwise exceed seal material limits.
2Duration of action of stationary object
If multiple seals are used to handle high pressure, then seal lifetime is extended, but the system complexity increases with additional pressure control units and gap sections
Solution Approach 1:
The system is segmented into modular units (seals, gap sections, pressure control units) that can be independently designed, analyzed, and maintained. This modularity manages complexity by breaking down the overall system into manageable components with defined functions, allowing each component to be optimized for its specific role while contributing to extended seal lifetime through controlled pressure distribution.
Solution Approach 2:
Pressure control units act as intermediary devices between the high-pressure chamber and the seals, actively regulating the pressure differential across each seal. These intermediaries protect the seals from direct exposure to full system pressure, extending their lifetime while adding controlled complexity only where needed for pressure management rather than throughout the entire system.
3Stress or pressure
If pressure is increased to handle deeper water reservoirs, then production capability is improved, but gas migration across seals occurs causing isolation liquid loss and seal degradation
Solution Approach 1:
The invention applies different pressure conditions to different locations within the sealing system. Each seal stage operates with a specifically controlled pressure differential tailored to its local requirements, rather than subjecting all seals to uniform high pressure. This local quality control prevents gas migration by maintaining pressure differentials that keep isolation liquid in contact with seals at each stage, eliminating the harmful effect of gas migration while enabling high-pressure operation.
Solution Approach 2:
The system actively changes and controls the pressure parameter at each seal location using pressure control units. By dynamically adjusting the pressure differential across each seal based on local conditions rather than maintaining uniform high pressure throughout, the system prevents gas migration and isolation liquid loss while still enabling production from high-pressure deep water reservoirs.
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 extends the sealing capabilities to higher pressures and temperatures, preventing gas migration and extending the life of primary and secondary seals by maintaining controlled pressure differentials and preventing overpressure, thus ensuring reliable operation in harsh environments.
Implementation Method 1
maintain the pressure in the isolation gap at a substantially constant pressure above the chamber pressure
Implementation Method 2
venting fluid from the isolation gap section when the pressure in the chamber drops
Data Source
AI summary
A pressure regulation system for a high pressure swivel comprises an annular inner wall and an annular outer wall, mutually rotatable around an axis, defining a toroidal chamber, and a gap extending axially between the walls from the chamber to an outer part. Positioned in the gap are an isolation seal, an isolation gap section, a primary seal, a primary gap section and a secondary seal. A first pressure control unit is connected to the chamber and to a pressurization device coupled to the isolation gap section for supplying fluid to the isolation gap section from the pressurization device.