Emergency Disconnect Package for Deepwater Early Production
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Solution Overview
Problem
Early production systems in high pressure and high temperature (HPHT) environments face challenges in safely disconnecting from wellheads and managing gas production, requiring advanced safety systems and multiple seafloor connections, while existing technologies often rely on dynamic positioning systems that lack the necessary redundancy and safety features.
Innovation Solution
The early production system incorporates an Emergency Disconnect Package (EDP) with a fail-safe close production valve, an Independent Production Control System (IPCS) with shut-down valves, sensors for pressure and temperature, and a control pod with logic electronics to manage pressure surges and disconnect operations, along with a flow base and umbilical system for safe and reliable gas handling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a dynamic positioning system is used instead of a full mooring system, then the system complexity and cost are reduced, but the safety and reliability during emergency disconnect operations deteriorate
Solution Approach 1:
The system is divided into modular components: a flow base with multiple seafloor connections, an emergency disconnect package with independent fail-safe valves, and a dynamically positioned vessel. This segmentation allows the DP system to function independently while maintaining safety through distributed control points at the wellhead, flow base, and vessel levels.
Solution Approach 2:
The system implements pre-positioned safety mechanisms including fail-safe close valves that automatically shut in case of emergency, pre-charged accumulators for immediate valve actuation, and multiple redundant disconnect points. These cushioning measures are built into the system design to prevent catastrophic failures during emergency disconnect operations.
2Adaptability or versatility
If multiple seafloor connections are implemented for early production, then the functionality and safety are improved, but the device complexity increases
Solution Approach 1:
The flow base is designed as a universal platform that can accommodate multiple seafloor connections (jumper connections to wellhead tree, LMRP connections, etc.) and perform multiple functions including production flow management, emergency disconnect, and safety valve operations. This multi-functional design consolidates what would otherwise require separate specialized equipment.
Solution Approach 2:
Multiple connection points and safety functions are merged into a single integrated flow base structure. The fail-safe close valves, control systems, and connection interfaces are combined in one location, reducing the overall system complexity compared to having distributed separate systems for each function.
3Reliability
If advanced safety systems such as HIPPS are added, then the safety and reliability are improved, but the device complexity and cost increase
Solution Approach 1:
The fail-safe close valves are designed to automatically actuate without requiring external control signals during emergency conditions. The pre-charged accumulators provide immediate actuation capability, and the system uses inherent pressure differentials and sensor inputs to trigger shutdown sequences, reducing the need for complex external control systems.
Solution Approach 2:
The accumulators are pre-charged with hydraulic fluid and the fail-safe valves are pre-positioned in the flow base with all necessary control connections made beforehand. This preliminary preparation allows immediate response to emergencies without requiring complex real-time control decisions or system reconfiguration.
4Reliability
If a fail-safe close valve is included in the EDP, then the safety during emergency disconnect is improved, but the device complexity increases
Solution Approach 1:
The fail-safe close valve function is extracted as a standalone component within the EDP, separated from the main production control system. This independent valve with its own actuation mechanism (pre-charged accumulator) can function autonomously during emergencies, simplifying the overall control architecture by removing interdependencies.
Data Source
AI summary
An early production system includes an Emergency Disconnect Package (“EDP”), a production riser coupled between the EDP and a sea surface processing facility, a gas export tubing coupled between the EDP and the sea surface processing facility, and a flow base. The flow base is detachably connectable to the EDP. The flow base also includes an Independent Production Control System (“IPCS”) for controlling at least one production valve.