Hydrate Plug Removal via Pressure Adjustment and Bypass Diversion
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Solution Overview
Problem
Deep sea oil and gas production is hindered by hydrate formation in flow lines, which leads to reduced or blocked flow, and existing methods of removing hydrates often require costly and disruptive depressurization of entire production lines, especially in hostile deep sea conditions.
Innovation Solution
A method and apparatus for fluidically isolating a hydrocarbon production station, diverting production flow to a bypass line, and adjusting pressure to melt hydrate plugs, using hydrate inhibitors like methanol and pressurized gas to selectively depressurize specific areas, such as subsea stations, without interrupting main production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the whole production line is depressurised to remove hydrate plugs, then hydrate plugs are melted and removed, but production is stopped and costs increase
Solution Approach 1:
The production line is divided into segments by installing isolation valves at strategic locations. This allows only the specific section containing hydrate plugs to be depressurised and treated, while other sections remain pressurised and continue production. The system segments the flow line into treatable zones using valve assemblies positioned at intervals along the pipeline.
Solution Approach 2:
Different pressure conditions are applied to different sections of the production line based on local needs. The affected section is depressurised to melt hydrates, while unaffected sections maintain normal operating pressure. This localized approach ensures that hydrate removal is applied only where necessary, preserving production continuity in unaffected areas.
2Reliability
If chemical inhibitors are used to prevent hydrate formation, then hydrate formation is reduced, but additional chemicals and cost are required
Solution Approach 1:
The system uses the production flow itself to deliver hydrate inhibitors through injection points along the pipeline. The flowing hydrocarbon mixture carries the inhibitor substances through the line, using the existing fluid dynamics rather than requiring separate injection systems. This self-service approach reduces infrastructure costs while maintaining effective hydrate prevention.
3Reliability
If temperature is increased to melt hydrate plugs, then hydrates are removed, but energy consumption increases and equipment may be damaged
Solution Approach 1:
The system exploits the pressure-temperature relationship of hydrate phase equilibrium. By reducing pressure in isolated sections, the hydrates undergo a phase transition from solid to liquid or gas state at the existing temperature, eliminating the need for external heating. This pressure-driven phase change is more energy-efficient than thermal methods and avoids equipment damage from excessive heat.
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
Enables the removal of hydrate plugs in targeted areas of the production line, preventing costly shutdowns and equipment damage, while maintaining continuous production by controlling pressure to melt hydrates without draining the entire line.
Implementation Method 1
adjusting the pressure in the production station to a level sufficient to melt the hydrate plugs
Implementation Method 2
fluidically isolating the production station; diverting production flow to a bypass line
Data Source
AI summary
A method for removing hydrate plugs in a hydrocarbon production station, the method comprising: fluidically isolating the production station; diverting production flow to a bypass line; and adjusting the pressure in the production station to a level sufficient to melt the hydrate plugs.