Downhole Gas Separator Vortex Control for Pump Cavitation
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Solution Overview
Problem
Conventional downhole gas and liquid separators face challenges in efficiently separating gas from liquids in oil and gas wells due to the compressibility of gases, leading to reduced pumping efficiency and potential pump lockage or cavitation, especially under advanced pressures and elevated temperatures.
Innovation Solution
A method involving a downhole gas separator with a separation chamber and a submersible pump that operates by partially vacating the chamber to allow sufficient space for gas to separate from liquid, using a vortex generator to centrifugally separate gas from liquid, and a flow restrictor to control fluid flow rates, ensuring the pump runs 'lean' to prevent cavitation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If gas separation is performed at the bottom of the tubing string before pumping, then pumping efficiency is improved, but pump lockage or cavitation may still occur due to gas compressibility
Solution Approach 1:
The patent applies preliminary action by performing gas separation before the pump processes the fluid. The separator removes compressible gases from production fluid prior to pump admission, preventing gas accumulation in the pump that would cause lockage or cavitation. This proactive separation approach addresses the reliability issue while maintaining pumping efficiency.
2Productivity
If the pump runs at high capacity, then production rates increase, but cavitation risk increases due to insufficient liquid level in the separation chamber
Solution Approach 1:
The patent implements feedback control by monitoring the liquid level in the separation chamber and using this information to control pump operation. When liquid level drops below a threshold, the system reduces pump capacity or shuts down the pump, preventing cavitation. This feedback mechanism allows the system to operate at high capacity when conditions permit while protecting against cavitation when liquid levels are insufficient.
Solution Approach 2:
The patent applies dynamics by making the pump capacity variable rather than fixed. The pump operates at different capacities depending on production conditions and liquid level in the separation chamber. This dynamic operation allows maximum production rates when liquid levels are adequate while preventing cavitation when levels drop, resolving the contradiction between productivity and cavitation prevention.
3Reliability
If the separation chamber is made larger to provide sufficient gas separation space, then gas separation efficiency improves, but device complexity and space requirements increase
Solution Approach 1:
The patent extracts the gas separation function from a large, complex separation chamber and implements it in a more compact configuration. By using a smaller separation chamber with strategic placement of internal components, the system achieves effective gas-liquid separation without requiring excessive space or complexity. This extraction approach maintains separation efficiency while reducing the overall size and complexity of the separator device.
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 approach enhances production rates and maintains fluid lifting efficiencies over variable production conditions, effectively preventing cavitation and improving the reliability of the pumping process by ensuring the submersible pump continuously empties the separation chamber.
Implementation Method 1
using a vortex generator to centrifugally separate gas from liquid
Implementation Method 2
Cavitation happens as cavities or bubbles form in pumped fluid, occurring at the low pressure or suction side of a pump. The bubbles collapse when passing to higher pressure regions
Data Source
AI summary
Separating gas from liquid down hole in a well by a downhole gas separator, gas is separated and passed to the well annulus and liquid is passed to a submersible pump at a calibrated flow rate at which liquid is vacated from a separation chamber, the length of the separation chamber providing sufficient space for gas separation as the liquid is pumped from the separator. The gas separator, limiting the amount of fluid passed to the separation chamber at less than the pumping rate of the submersible pump, creates a fluid vortex causing the separated liquid to move to the periphery and separated gas to pass near the axial center of the separation chamber. The separated gas passes to the well annulus and the liquid passes to the inlet of the submersible pump.