Wear features of high-speed submersible pumps for oil production

UDK: 621.671:620.178:534-16
DOI: 10.24887/0028-2448-2021-1-62-65
Key words: electric centrifugal submersible pump (ESP), abrasive wear, erosive wear, abrasive particles, test benches
Authors: N.I. Smirnov (Mechanical Engineering Research Institute of RAS, RF, Moscow; RUDN University, RF, Moscow)

One of the promising directions for further improvement and improvement of the operational efficiency of submersible installations of electric-driven pumps (ESP) for oil production is to increase the rotation frequency of the rotor of the installation. When increasing the pump speed the pressure per pump stage increases, the number of pump stage is significantly reduced as well as the length of the installation. This allows to assemble the unit in the shop and assemble it on the well, reduces costs and increases the reliability of installation operations. The performance of a shorter installation is less dependent on the curvature of the well. In an expert opinion, high speed positively effects on the process of reservoir fluid dispersion and gas separation. One of the reasons for the low distribution of high-speed ESP is their lower resource compared to traditional equipment. The lack of reliable failure statistics, the low level of knowledge of wear and dynamics at high speed, and the lack of appropriate test benches create additional methodological difficulties. For high-speed ESP, more stringent requirements are set for the gaps of mobile interfaces to ensure high values of the pump stage head and low rotor dynamics. Therefore, the materials must have high wear resistance. 

The purpose of this work was to study the wear processes of mobile interfaces, the flow part of the pump stage in water with an abrasive when the speed changes. The pump stage 5–50 was tested. It was found that when rotation speed increased from 2950 to 5705 rpm, the wear rate of the radial interfaces increased by 5.8 times, and the wear rate of the axial interfaces increased by 2.5 times. The wear rate of hard alloy bearings depends linearly on the speed and flow rate. The imbalance of the impeller has little effect on the wear of the radial interfaces. The wear rate of the flow part of the impellers increased by 2.6 times, the wear rate of the flow part of the guide device – by 11 times. A test bench with a rotation speed of up to 12000 rpm has been developed for testing high-speed pump stages. When testing a high-speed pump stage with a rotation speed of 9500 rpm, low values of the wear rate of mobile interfaces made of hard alloy were obtained. The dependence of the wear rate of pump stage materials in a corrosive environment on the content of alloying elements is obtained.

References

1. URL: https://www.lepse.com/products/159/

2. Smirnov N.I., Grigoryan E.E., Study of the impact of wear of movable interfaces on failures of an immersible electrically operated vane pump for oil extraction (In Russ.), Problemy mashinostroeniya i nadezhnosti mashin = Journal of Machinery Manufacture and Reliability, 2019, no. 1, pp. 92–97.

3. Litvinenko K.V., Zdol'nik S.E., Mikhaylov V.G., An approach to ESP characteristics degradation modeling under high erosive wear conditions (In Russ.), Neftyanoe khozyaystvo = Oil Industry, 2014, no. 12, pp. 132–135.

4. Ostrovskiy V.G., Upravlenie vtorichnymi techeniyami v stupenyakh neftyanykh nasosov dlya snizheniya ikh gidroabrazivnogo iznosa (Control of secondary flows in the stages of oil pumps to reduce their hydroabrasive wear): thesis of candidate of technical science, Perm', 2013. 

5. Patent RU 2444719 C2, Method of testing materials for hydroabrasive and corrosion wear, Inventors: Smirnov N.I., Smirnov N.N.

6. Smirnov N.I., Yagovkina A.N., Prozhega M.V., Smirnov N.N., Development of methods for materials erosion tests (In Russ.), Mashinostroenie i inzhenernoe obrazovanie, 2017, no. 2(51), pp. 60–68

One of the promising directions for further improvement and improvement of the operational efficiency of submersible installations of electric-driven pumps (ESP) for oil production is to increase the rotation frequency of the rotor of the installation. When increasing the pump speed the pressure per pump stage increases, the number of pump stage is significantly reduced as well as the length of the installation. This allows to assemble the unit in the shop and assemble it on the well, reduces costs and increases the reliability of installation operations. The performance of a shorter installation is less dependent on the curvature of the well. In an expert opinion, high speed positively effects on the process of reservoir fluid dispersion and gas separation. One of the reasons for the low distribution of high-speed ESP is their lower resource compared to traditional equipment. The lack of reliable failure statistics, the low level of knowledge of wear and dynamics at high speed, and the lack of appropriate test benches create additional methodological difficulties. For high-speed ESP, more stringent requirements are set for the gaps of mobile interfaces to ensure high values of the pump stage head and low rotor dynamics. Therefore, the materials must have high wear resistance. 

The purpose of this work was to study the wear processes of mobile interfaces, the flow part of the pump stage in water with an abrasive when the speed changes. The pump stage 5–50 was tested. It was found that when rotation speed increased from 2950 to 5705 rpm, the wear rate of the radial interfaces increased by 5.8 times, and the wear rate of the axial interfaces increased by 2.5 times. The wear rate of hard alloy bearings depends linearly on the speed and flow rate. The imbalance of the impeller has little effect on the wear of the radial interfaces. The wear rate of the flow part of the impellers increased by 2.6 times, the wear rate of the flow part of the guide device – by 11 times. A test bench with a rotation speed of up to 12000 rpm has been developed for testing high-speed pump stages. When testing a high-speed pump stage with a rotation speed of 9500 rpm, low values of the wear rate of mobile interfaces made of hard alloy were obtained. The dependence of the wear rate of pump stage materials in a corrosive environment on the content of alloying elements is obtained.

References

1. URL: https://www.lepse.com/products/159/

2. Smirnov N.I., Grigoryan E.E., Study of the impact of wear of movable interfaces on failures of an immersible electrically operated vane pump for oil extraction (In Russ.), Problemy mashinostroeniya i nadezhnosti mashin = Journal of Machinery Manufacture and Reliability, 2019, no. 1, pp. 92–97.

3. Litvinenko K.V., Zdol'nik S.E., Mikhaylov V.G., An approach to ESP characteristics degradation modeling under high erosive wear conditions (In Russ.), Neftyanoe khozyaystvo = Oil Industry, 2014, no. 12, pp. 132–135.

4. Ostrovskiy V.G., Upravlenie vtorichnymi techeniyami v stupenyakh neftyanykh nasosov dlya snizheniya ikh gidroabrazivnogo iznosa (Control of secondary flows in the stages of oil pumps to reduce their hydroabrasive wear): thesis of candidate of technical science, Perm', 2013. 

5. Patent RU 2444719 C2, Method of testing materials for hydroabrasive and corrosion wear, Inventors: Smirnov N.I., Smirnov N.N.

6. Smirnov N.I., Yagovkina A.N., Prozhega M.V., Smirnov N.N., Development of methods for materials erosion tests (In Russ.), Mashinostroenie i inzhenernoe obrazovanie, 2017, no. 2(51), pp. 60–68


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