APPROACH TO THE PROCESS OF MANUFACTURING OF THE MUD-PUMP BIMETAL LINERS AND THEIR OPERATIONAL CHARACTERISTICS

On the ground of the operation test of the mud-pump bimetal liners, it was estimated that the mud-pump bimetal liners, manufactured under the typical technical conditions, break down not only because of the hydroabrasive wear, but also because of the influence of the working surface corrosion cracking which is intensified by the cavitation in the ?bushing ? piston? junction area. Due to the comparison of the data of the examination it was demonstrated that the usage of the bimetal liners will increase the overhaul life and decrease the repair costs. The analysis of the typical technical conditions of the liners’ manufacturing has proved that there is a necessity to use the mud-pump bimetal liners. The article reveals the damage mechanism of the Piston and Cylinder Unit of the mudpumps applied in the global practice while drilling to extract oil and gas. It was found out that the damage of the Piston and Cylinder Unit by the abrasive jet happens either when the abnormal fluid leakage from the decreasing space of the cylinder into the increasing space, which is formed after the wear of the unit by the abrasive layer, takes place or as a result of the alternative displacement of the layer from one piston cup to another by the lubricating fluid. A specific feature of the second damage subtype is the fact that it generally takes place at the high pressure pumps. The role of the technological heredity in the formation of the performance characteristics and the reliability coefficients was established. The failure causes of the mud-pump liners as well as the techniques for producing of the existing mud-pumps were analyzed. The main types and groups of the mud-pump bimetal liner wear were systematized and summarized in the table. The cyclic influence of the hydrodynamic loads and the existence of the corrosion environment lead to considerable decrease of the long-term strength of the corrosion cracking of the liner working surface. It was defined that besides the stress-strain properties of the working surfaces, topography of the surface has the great influence on the liner’s resistance to wear as it determines the possibility of the penetration of abrasive and the drilling mud inhibitors into the area of contact and as a result, the abrasion process is intensified by the propping action of the drilling mud. The above mentioned facts give the evidence of the inadequacy of the usage of the typical technical conditions of the mud-pump bimetal liners’ manufacturing. The contrastive table for the comparison of the steel and bimetal liners was designed. It demonstrates that the main economic effect caused by the usage of the high-resource bimetal liners is obtained due to the increase of the overhaul life and decrease of the repair costs correspondingly. The results of the experimental research were illustrated, the findings were analyzed and the ways of the follow-up study were indicated.