Equal-Walled Gerotor Pump for High Gas Volume Wellbore Fluids
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Solution Overview
Problem
Current pumps used in wellbore applications, such as Progressive Cavity Pumps and Twin-Screw Pumps, face limitations in handling high gas volume fractions, require complex designs and costly manufacturing, and are inefficient due to rapid performance degradation with gas presence, especially in ESP systems.
Innovation Solution
A gerotor pump design featuring an inner rotor with multiple teeth and a hollow outer rotor, where the outer rotor has a wall of equal thickness, allowing for fluid passage between the rotor and housing, enabling efficient multiphase fluid handling and heat transfer, and potentially reducing the need for gear reduction with conventional electric motors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional pumps (PCP, Twin-Screw) are used in wellbore applications, then they can transport fluids, but they experience rapid performance degradation when handling high gas volume fractions
Solution Approach 1:
The pump divides the fluid handling space into multiple discrete chambers formed by the rotor teeth and housing. Each chamber acts as an independent compression and transport unit, allowing the pump to efficiently handle multiphase fluids with high gas volume fractions by processing gas and liquid separately in each chamber while maintaining overall system reliability
Solution Approach 2:
The invention inverts the traditional approach by using a progressive cavity pump as the driver and driving a gerotor pump through mechanical coupling, rather than using the gerotor pump as the primary driver. This inversion allows the system to leverage the robust multiphase handling capabilities of the PCP while achieving the compact design and high gas fraction tolerance of the gerotor mechanism
2Productivity
If Progressive Cavity Pumps are used for artificial lift, then they can transport fluid, but they require complex designs and costly manufacturing
Solution Approach 1:
The invention merges the progressive cavity pump and gerotor pump into a single integrated unit where the PCP stator and rotor are directly coupled with the gerotor pump components. This consolidation eliminates the need for separate drive mechanisms, mechanical seals, and coupling systems, thereby reducing design complexity and manufacturing costs while maintaining fluid transport capability
Solution Approach 2:
The gerotor pump housing serves multiple functions: it acts as the pump chamber for the gerotor mechanism, the mechanical seal housing, and the drive coupling for the progressive cavity pump. This multi-functionality reduces the number of separate components needed, simplifying the overall design and reducing manufacturing complexity
3Power
If conventional pumps are used in ESP systems, then they can provide artificial lift, but they are inefficient due to rapid performance degradation with gas presence
Solution Approach 1:
The pump segments the fluid stream into discrete chambers that can independently handle gas and liquid phases. This segmentation prevents gas slugging and maintains positive displacement efficiency even with high gas volume fractions, thereby maintaining both power output and productivity in ESP applications
Solution Approach 2:
The invention changes the operational parameters by maintaining constant rotor speed and positive displacement volume per revolution regardless of gas content. The progressive cavity mechanism ensures consistent stroke volume while the gerotor coupling transmits this motion efficiently, maintaining pump efficiency and power output across varying gas fractions
4Adaptability or versatility
If equal-walled outer rotor is used in gerotor pump, then it allows fluid passage between rotor and housing, but it requires precise manufacturing to maintain equal wall thickness
Solution Approach 1:
The invention uses an asymmetric manufacturing approach where the outer rotor is formed with a mandrel that creates the internal cavity shape. The equal wall thickness is achieved through the mandrel design rather than requiring post-manufacturing adjustment, allowing fluid passage capability while managing manufacturing precision requirements through tooling design
Data Source
AI summary
One example of a gerotor pump includes an inner rotor comprising multiple teeth, the inner rotor configured to rotate about a first longitudinal gerotor pump axis. The gerotor pump also includes a hollow outer rotor including an outer surface and an inner surface having substantially identical contours, the inner surface configured to engage with the multiple teeth and to rotate about a second longitudinal gerotor pump axis. The pump includes a pump housing within which the inner rotor and the outer rotor are disposed, wherein the outer surface of the outer rotor defines gaps between the pump housing and the outer rotor.