Research on Paraffin Deposition Law and Paraffin Removal-Prevention Technology of Rodless Lifting Wellbore

The rodless lifting technology can overcome the shortcomings of rod and tube wear, high energy consumption and heavy maintenance workload in the lifting process of rod pumps, which is gradually being developed and adopted by major oil fields around the world. However, the paraffin deposition is coming more and more serious duo to non-sucker rod disturbance in wellbore and the relatively slow flow rate of well fluid, the production and maintenance cost are increasing, the pump inspection cycle is shortened, which creates a bottleneck for the further popularization of rodless lifting technology. Therefore, the research and development of rodless lifting oil well paraffin removal-prevention technology is great significance to the application and promotion of rodless lifting technology. Based on the study of paraffin deposition in oil wells, the effects of paraffin content, fluid flow rate, gelatin, wall temperature and other factors on paraffin deposition in crude oil are analyzed, to discuss the internal relationship. By the laboratory tests, the mathematical model of paraffin deposition in rodless lifting wellbore is obtained. Field tests were carried out to verify the paraffin control effect of the developed solid paraffin inhibitor matched with the paraffin deposition law and mathematical model of rodless lifting wellbore. Field tests show that the period of heat-free washing of rodless lifting wells is more than half a year after the application of solid paraffin inhibitors, and the effect of paraffin control is obvious. The research and development of paraffin removal and prevention technology is of great significance to the popularization and application of rodless lifting technology. The research and development of paraffin removal-prevention technology is important for the popularization and application of rodless lifting technology