Subsea Diverter System Gravity Flow Mud Gas Separator
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Solution Overview
Problem
Current diverter systems for subsea drilling face challenges in safely handling hydrocarbons in liquid or dense phase, as they often lead to overfilling of mud/gas separators, resulting in limited time for action and potential leakage, as seen in the Deepwater Horizon disaster, due to high accelerating mud flows and gas expansion.
Innovation Solution
A fluid diverter system with a mud/gas separator (MGS) arranged below the diverter line outlets, allowing gravity-fed flow to the MGS, featuring interlocked valves to open the diverter valve before closing the diverter element, ensuring safe venting of gas overboard and return of mud to the system, even during high-pressure conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the MGS is positioned above the diverter line outlets to enable gravity flow, then the flow rate to MGS increases, but the MGS overfills and vents line fills causing safety risks
Solution Approach 1:
The patent inverts the conventional arrangement by positioning the MGS below the diverter line outlets instead of above. This inversion allows gravity to assist flow to the MGS while preventing overfilling and vent line accumulation, thereby maintaining both productivity and safety
Solution Approach 2:
The patent changes the vertical dimension of the MGS positioning from above to below the diverter line outlets. This dimensional change fundamentally alters the flow dynamics and safety characteristics of the system
2Reliability
If the diverter element closes after the BOP to handle kicks, then hydrocarbon containment improves, but gas expansion in the riser pushes mud back accelerating flow rate beyond MGS capacity
Solution Approach 1:
The patent opens the diverter valve before closing the diverter element, preparing the discharge path in advance. This preliminary action ensures that when high-flow mud returns from the riser, the diverter is already positioned to handle the flow, preventing overfilling of the MGS and vent line
3Productivity
If the MGS capacity is increased to handle high flow rates, then the system can accommodate higher mud return rates, but the device complexity and space requirements increase
Solution Approach 1:
Instead of increasing MGS capacity to handle high flow rates, the patent inverts the MGS positioning below the diverter line outlets. This inversion uses gravity and pressure differentials to maintain flow capacity without requiring a larger MGS, thereby avoiding increased device complexity and space requirements
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
This design enhances safety by allowing gravity-fed flow to the MGS, preventing overfilling and leakage, enabling timely and safe management of hydrocarbons, reducing the risk of accidents like the Deepwater Horizon disaster, and facilitating a two-stage degassing process for drilling fluids.
Implementation Method 1
the mud/gas separator arranged below the outlet of the diverter line, whereby riser fluids may be fed from the diverter housing to the mud/gas separator by means of gravity flow
Data Source
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AI summary
A fluid diverter system for a drilling facility comprises a diverter housing (15; 15') fluidly connected to a tubular (3, 42, 43) extending to a subsea well. The diverter housing (15; 15') comprising a movable diverter element (2) for closing off the diverter housing, a first fluid conduit (44) connected to a mud system and comprising a first valve (5), at least one second fluid conduit (20; 20') leading from an outlet (46; 46') in the diverter housing to an overboard location and comprising a second valve (1; 48), and a third fluid conduit (16) connected to a mud/gas separator (MGS) (13) and comprising a third valve (4). The MGS (13) is arranged below the outlet (50) of the diverter line, whereby riser fluids may be fed from the diverter housing (15) to the MGS (13) by means of gravity flow. The diverter valve (1; 48) on a leeward side of the drilling facility is configured to be open before the diverter element (2) closes around the tubular (3).