Subsea Boost Pump Recirculation for Gas-Liquid Separation
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Solution Overview
Problem
Subsea well pumps, particularly centrifugal pumps, face performance issues due to high gas content in well fluids, and existing systems lack an efficient method to selectively inject chemicals while boosting fluid flow.
Innovation Solution
A subsea well production system that integrates a sea floor boost pump with a recirculation line and chemical injection capabilities, using intake and outlet fluid conditioners to manage gas and liquid separation and chemical delivery, allowing for both production flow boosting and chemical injection modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a subsea boost pump is used to increase drawdown and boost production pressure, then fluid flow from the well is improved, but the pump performance is detrimentally affected by high gas content in the well fluids
Solution Approach 1:
The system segments the fluid stream by introducing a recirculation line that separates liquid-rich portions from gas-rich portions. The recirculation line taps into the discharge and returns liquid to the intake, effectively segregating phases before the pump intake to improve pump performance while maintaining productivity
Solution Approach 2:
The recirculation line acts as an intermediary mechanism that mediates between the pump discharge and intake. It provides a pathway for liquid-rich fluid to bypass the gas separation issue and return directly to the intake, protecting the pump from gas locking while maintaining flow
2Adaptability or versatility
If a separate chemical injection pump is used to inject chemicals into the well, then chemical injection capability is provided, but the system complexity increases
Solution Approach 1:
The system merges the chemical injection function with the existing boost pump system. The chemical injection pump is integrated into the recirculation line infrastructure, allowing chemicals to be injected through the same recirculation pathway used for liquid enrichment, thereby reducing overall system complexity
Solution Approach 2:
The recirculation line is designed to serve multiple functions: it enriches the pump intake with liquid-rich fluid during production mode and simultaneously serves as the injection pathway for chemicals when needed. This multi-functionality eliminates the need for separate dedicated chemical injection infrastructure
3Reliability
If a recirculation line is used to divert liquid-rich phase back to the pump intake to reduce gas content, then pump performance is improved, but the system complexity increases
Solution Approach 1:
The recirculation line incorporates adjustable flow control elements that allow the liquid enrichment ratio to be dynamically adjusted. This enables optimization of pump performance while controlling the complexity of liquid handling, allowing operators to adapt the recirculation rate to match production conditions
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
Enhances fluid flow by managing gas content and enables effective chemical injection, improving well production efficiency by reducing gas locking and optimizing chemical distribution within the well.
Implementation Method 1
A recirculation line extends from the boost pump outlet conduit to the subsea tree conduit... diverting a portion of the well fluid back through the recirculation line to the subsea tree conduit
Implementation Method 2
The intake fluid conditioner has means for separating heavier and lighter components in the well fluid flowing from the subsea tree and forming a storage reservoir of liquid
Implementation Method 3
The subsea boost pump increases the drawdown on the well, boosting the pressure of the produced fluids to overcome pipeline and hydrostatic losses
Implementation Method 4
A chemical injection source line extends from a chemical injection source and is connected to the subsea tree conduit... causing the boost pump to pump the chemical from the chemical source through the recirculation line into the subsea tree conduit
Data Source
AI summary
A subsea well production system includes a subsea boost pump coupled with a subsea tree conduit having a valve in the subsea tree conduit. A boost pump outlet conduit connects between a discharge of the boost pump and an outlet flow line. A recirculation line extends from the boost pump outlet conduit to the subsea tree conduit. A chemical injection line having a chemical source valve extends from a chemical injection source and is connected to the subsea tree conduit at a point between the valve in the subsea tree conduit and the intake of the boost pump. During production flow boosting, the boost pump pumps well fluid. During chemical injection, the boost pump pumps chemicals into the subsea tree.