Frac Pump Bypass Routing for High-Pressure Start and Shutdown
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Solution Overview
Problem
Frac pumps with electric motors face difficulties in starting-up and shutting down due to high pressure, which inhibits torque production and can lead to damage from sudden pressure changes.
Innovation Solution
Implementing flow paths and configurations that reduce or eliminate pressure on the pumping device during startup and shutdown, allowing the electric motor to spin up efficiently and reducing resistive forces, thereby maintaining optimal operating conditions and preventing damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If the electric motor operates under high pressure, then the pump can maintain operating pressure, but the electric motor cannot start-up or shut down efficiently due to insufficient torque
Solution Approach 1:
The system performs preliminary actions by opening discharge valves and routing fluids through bypass lines before the electric motor starts up. This eliminates pressure buildup that would otherwise resist motor rotation, allowing the motor to spin up freely before pressure is gradually applied during operation.
Solution Approach 2:
The system dynamically switches fluid routing configurations during different operational phases. During start-up, the system uses a low-resistance flow path that bypasses the high-pressure discharge line. During normal operation, the system transitions to the high-pressure discharge configuration. This dynamic adaptation allows the motor to operate efficiently across different pressure conditions.
2Stress or pressure
If the electric motor operates under high pressure, then the pump can maintain operating pressure, but the electric motor experiences difficulty shutting down due to residual pressure and sudden torque changes
Solution Approach 1:
Before shutting down the electric motor, the system performs preliminary actions by opening discharge valves and routing fluids through bypass lines to gradually reduce pressure. This preliminary pressure reduction prevents sudden torque changes and residual pressure from damaging the driveline or causing the pump to spin backwards during shutdown.
Solution Approach 2:
The system provides beforehand cushioning by using bypass lines and flow control valves to gradually dissipate residual pressure before the motor stops. This cushioning effect prevents abrupt pressure changes from causing mechanical damage to the driveline, pump gearbox, or other components during the shutdown transition.
3Productivity
If multiple frac pumps operate in parallel, then the system can maintain high productivity, but shutting down a single pump for maintenance requires shutting down all pumps
Solution Approach 1:
The system segments the fluid flow paths for each frac pump using individual isolation valves and bypass lines. This segmentation allows each pump to be independently controlled and maintained without affecting the operation of other pumps in the parallel system, enabling individual pump repairs while maintaining overall system productivity.
Solution Approach 2:
The system introduces intermediary components such as isolation valves, bypass lines, and flow control devices between the pumps and the common discharge manifold. These intermediaries allow fluid from operating pumps to be redirected through bypass paths, isolating the pump under maintenance from the high-pressure system while maintaining continuous operation of the remaining pumps.
Data Source
AI summary
Some implementations include a system comprising a first tubular fluidically connected with one or more frac pumps and one or more first flow control devices that are fluidically connected to a second tubular that is fluidically connected to a wellhead. The system also may include a third tubular fluidically connected with the first tubular and one or more second flow control devices that are connected with a fourth tubular that is fluidically independent of the wellhead.