ESP Gas Slug Processor With Reservoir-Based Liquid Retention
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Solution Overview
Problem
Gas slugs in electric submersible pumps (ESPs) can cause gas lock, leading to operational inefficiencies, bearing wear, and increased maintenance costs due to interrupted fluid flow and lubrication, particularly in wells with low reservoir pressure or high gas/oil ratios.
Innovation Solution
A gas separator assembly with internal fluid reservoirs and centrifugal pump stages that separate gas and liquid phases, retaining liquid for extended periods to maintain lubrication and cooling of bearings, even during gas slug events.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If gas separator assembly with internal fluid reservoirs is implemented, then gas lock mitigation is improved, but device complexity increases
Solution Approach 1:
The patent implements nesting by placing fluid reservoirs concentrically around the drive shaft within the gas separator assembly housing. The first fluid reservoir is positioned between the drive shaft and the first centrifugal pump stage, while the second fluid reservoir is positioned between the drive shaft and the second centrifugal pump stage. This nested arrangement allows multiple functional components to occupy the same spatial envelope, reducing overall device complexity while maintaining the gas lock mitigation function.
Solution Approach 2:
The gas separator assembly is segmented into distinct functional zones: a first fluid reservoir for retaining liquid during gas slug events, a second fluid reservoir for additional liquid retention, first and second centrifugal pump stages for fluid movement, and a drive shaft for mechanical power transmission. This segmentation allows each component to perform its specific function independently while working together to mitigate gas lock conditions.
2Reliability
If liquid is retained in fluid reservoirs during gas slug events, then bearing lubrication is improved, but fluid flow interruption increases
Solution Approach 1:
The fluid reservoirs are pre-filled with liquid during normal operation before gas slug events occur. This preliminary accumulation of liquid in the reservoirs ensures that when gas slugs arrive and interrupt main fluid flow, the bearings continue to receive lubrication from the pre-stored liquid in the reservoirs, preventing bearing damage during the flow interruption period.
Solution Approach 2:
The fluid reservoirs act as intermediaries between the interrupted main fluid flow and the bearings. During gas slug events, when the main fluid flow is blocked, the reservoirs release stored liquid to the bearings, mediating the lubrication need and allowing the system to bridge the gap between flow interruption and bearing protection requirements.
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
The solution effectively mitigates gas lock conditions, prolongs ESP operation, reduces maintenance frequency, and maintains fluid flow by ensuring continuous lubrication and cooling of bearings, even during prolonged gas slug occurrences.
Implementation Method 1
A gas separator assembly with internal fluid reservoirs and centrifugal pump stages that separate gas and liquid phases
Implementation Method 2
retaining liquid for extended periods to maintain lubrication and cooling of bearings
Data Source
AI summary
A downhole gas separator assembly. The gas separator comprises a drive shaft; a first fluid mover mechanically coupled to the drive shaft having a fluid inlet and a fluid outlet; a fluid reservoir concentrically disposed around the drive shaft and located downstream of the first fluid mover, wherein an inside surface of the fluid reservoir and an outside surface of the drive shaft define a first annulus that is fluidically coupled to the fluid outlet of the first fluid mover; a second fluid mover having a fluid inlet and a fluid outlet, wherein the second fluid mover is located downstream of the fluid reservoir, and wherein the fluid inlet of the second fluid mover is fluidically coupled to the first annulus; and a gas flow path and liquid flow path separator having a gas phase discharge port open to an exterior of the assembly and a liquid phase discharge port.