Development And Application Of PCP Special Pumping Rod With Middle Displacement

PCP lifting technology has got a great progress through perfecting and matching it for recent years. PCP lifting technology with little displacement at field trial may be popularized industrialization, since the PCP technology has been perfected day by day. The PCP pumping rod with middle displacement exposed to a serious problem or breaking drop out to limit that PCP with middle displacement would be largely popularized at the oilfield. It is necessary to develop a special pumping rod matching PCP with middle displacement.In recent years, some domestic manufactures has begun to develop and apply PCP anti-dropout pumping rod. Daqing oil production engineering institute and No. 3 production plant are representative, and the preliminary result has been got. The inserted and connected structure are used in the pumping rod. There are some problems to be solved. The main question is that the pumping rod life would not satisfy the needs of the field since the manufacturing technology is not stable. The report about the anti-dropout pumping rod has not been seen abroad.We analyzed the main reason to make the pumping rod dropout through making spot test and tackling key problems technically. The common pumping rod connector shape is poorly suitable to PCP, and the pumping rod material and its processing quality have also some problems and so on. On the basis of researching the PCP rod design and manufacturing method, the pumping rod material and connector shape are studied and designed completely and systematically to present the research approach and method for tackling key problems technically, at the same time to give technical support for popularizing PCP.The problem of pumping rod dropout was settled through inserted-connected structure and cone thread structure. The structural parameters are optimized by finite element method to analyze the stress connection problem of rod head, realizing the uniform strength design of PCP special pumping rod. As to the pumping rod processing, the forged temperature and reasonably determining forging ratio. The thermal refining defect of rod head was eliminated by the tracking preheat treatment of rod head to improve the reliability of the pumping rod application.On the basis of above comprehensive research, PCP special pumping rods were tested at field in 1320 wells. The longest running time was 821d. The dropout ratio of rod string matching PCP with middle displacement decreased from 26% to 6.9% to meet the needs of field.