Subsea Wellhead Fluid Delivery Control System
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Solution Overview
Problem
Current methods for delivering pressurized fluids, such as acid, to subsea hydrocarbon wells require the use of a jack-up rig and workover riser, which are costly and complex, and do not allow for the direct pumping of large OD balls or efficient control of fluid injection operations from a vessel.
Innovation Solution
A method for delivering pressurized fluids directly from a pumping vessel to a subsea wellhead without relying on a jack-up rig, using a control system that allows for remote control of certain functions from the vessel and downhole data transmission via radio link, enabling emergency shut-off, fluid rate, and pressure control, while maintaining control of the subsea control module on the host production platform.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a jack-up rig and workover riser are used for delivering pressurized fluids to subsea wells, then the system can provide robust support and control, but the operational cost and device complexity increase significantly
Solution Approach 1:
The patent extracts the essential function of fluid delivery from the complex jack-up rig and workover riser system, isolating only the necessary control functions (emergency shut-off, fluid rate control, pressure control) to be performed from the pumping vessel. This separates the delivery function from the supporting infrastructure, reducing overall system complexity while maintaining reliability through selective remote control capability.
Solution Approach 2:
The patent introduces a radio link as an intermediary communication channel between the pumping vessel and the subsea well control system. This intermediary enables remote control and monitoring without requiring direct physical connection through complex riser systems, simplifying the overall architecture while maintaining control capability.
2Reliability
If a jack-up rig and workover riser are used for delivering pressurized fluids to subsea wells, then the system can provide robust support, but the operational cost increases significantly
Solution Approach 1:
The patent extracts the fluid delivery function from the expensive jack-up rig platform, allowing it to be performed from a simpler pumping vessel. Only essential control functions are retained on the host production platform, while the majority of the operation (fluid delivery) is moved to a more cost-effective mobile vessel, significantly reducing daily operational costs.
Solution Approach 2:
The pumping vessel is equipped with independent control capabilities for essential functions (emergency shut-off, fluid rate control, pressure control), allowing it to perform stimulation operations autonomously without requiring continuous support from the expensive jack-up rig infrastructure. This self-sufficiency reduces dependency on high-cost platform resources.
3Device complexity
If direct connection from pumping vessel to subsea well is implemented, then cost and complexity are reduced, but control capability and safety may be compromised
Solution Approach 1:
The patent establishes preliminary control arrangements by pre-configuring the pumping vessel with independent control systems for emergency shut-off, fluid rate control, and pressure control. These control capabilities are prepared in advance on the vessel, ensuring that safety and operational control are maintained from the outset without requiring complex intermediate control systems.
Solution Approach 2:
The patent implements feedback mechanisms through the radio link connection, enabling real-time monitoring and control adjustment between the pumping vessel and the subsea well. This feedback loop ensures that control capability is maintained despite the simplified direct connection architecture, allowing operators to respond to downhole conditions and adjust delivery parameters as needed.
Data Source
Figure 1
AI summary
The invention relates to the fluid treatment, such as acid stimulation, of a subsea hydrocarbon well via a subsea wellhead/Christmas tree. Fluid is delivered directly to the subsea wellhead from a pumping vessel. Control of the delivery of fluid is from the pumping vessel via a fail-safe close valve in the delivery line. The Christmas tree subsea module is controlled directly from a host platform via a subsea cable, whilst a radio data link between the vessel and host platform provides communication of downhole data to the pumping vessel during the operation.