Possibility of using aluminum alloys to manufacture stages of electric submersible centrifugal pumps
During oil production intensification, a well fluid more often includes a large amount of free gas and mechanical impurities. It leads to a significant degradation of pump characteristics due to their flow channels overlap by gas accumulations, clogging of these channels by mechanical impurities, rapid wear-out of the main working surfaces of the stages. One of the variants of the above-mentioned problems solution is the use of electric submersible centrifugal pumps (ESP), the stages of which are equipped by open impellers (OI). These impellers are less susceptible to scaling, reduce the mounting height of the stages, the rotor’s weight and unbalance, the installation vibration during operation, especially at high speeds. The construction of open impellers allowed to part with foundry technology and to use V-95T aluminum alloy with a micro-arc oxidation (MAO) of the working surfaces as a structural material. This material properties allow to reduce scaling, corrosion and wear-out. The mass of the impellers made of V-95T aluminum alloy is 7 times less than the mass of the standard impeller. The OI surface microhardness amounted to HV 1000…1200. Bench tests proved the fact that OI manufactured of the aluminum alloy coated by MAO have wear-out resistance almost equal to the parts made of hard alloy. The created stages were bench tested in Gubkin Russian State University of Oil and Gas as well as at the ESP stand test in LLC "Izhnefteplast". The pump sections that are assembled from pump stages with open impellers made of aluminum alloy with MAO coating are now experimentally tested in the wells of LLC "LUKOIL-Western Siberia".