Most of the domestic oilfields have entered the period of high water cut. Conventional plunger pumps are one of the major oil recovery methods. Due to factors such as high sand content, high water content and high temperature steam heavy oil exploitation, polymer injection and strong corrosive media environment and poor well conditions, the average time for piston pump repair is shorter and shorter, and some are even less than 30 Day you need to check the pump, seriously affecting the comprehensive economic benefits of oil field development. The reasons for the failure of the plunger pump in each oilfield are different, and are combined into the following factors: oil well water discharge, sand production, composition of injection, degree of salinity, bottom hole temperature, corrosion rate of effluent, well structure and Plunger pump itself structure, plunger and pump cylinder surface treatment and surface materials. The main reasons for the failure are as follows: sand sedimentation in the pipe string sand output is large, high water content, formation oil sand mixed in the formation of water. Since the carrying capacity of different media is proportional to the viscosity of the medium, the viscosity of the crude oil is far greater than the viscosity of the formation water. The formation water has poor sand carrying capacity at the same flow rate, and some sand particles will sink under gravity, Cause card pump and sand buried. Before the pump is completely stuck, the relative movement of the plunger and the barrel can cause scratches on the surface of the plunger and the inner surface of the barrel. Large amounts of scratches can reduce the pump efficiency. Dual Role of Wear and Corrosion If sand enters the pump barrel and plunger and the wear on the surface of the plunger and pump barrel increases, if the surface layer is worn out to expose the substrate, the core can be easily damaged due to the strong electrolytes and weak acids of the well fluid medium Corrosion and wear. In addition, the general pressure difference between the two ends of the piston is 7-14MPa, in the high pressure drop, sand-containing liquid will produce hydraulic cutting plunger and pump cylinder, exacerbate wear and tear. Plunger and pump cylinder fouling If the injection of water untreated recycling, coupled with some oilfield water injection has been unable to meet the enhanced oil recovery and the use of polymer injection, so that downhole fluid composition becomes more and more The more complex and more salinized, the more likely it is to scale on the plunger and barrel. When deposits on the surface of the plunger and pump cylinder become denser and the adhesion becomes stronger, the hazard increases. In some areas, the typical plunger pump pickup cycle has been reduced from 300 days to 30 days due to fouling. The structure of the oil pump Ordinary oil pump in the structure without any sand grit removal measures, and the end of the plunger has a cone surface, the pump reciprocating motion, making the sand directly settled to the gap between the plunger and the pump cylinder, and The sucker on the plunger of the sump only with sand and sand scraping performance, the defoaming sand grit removal is not considered, after the sanding sand, the same will cause the plunger pump wear. Surface treatment and material selection studies of the plunger and barrel indicate that the selection of the pump plunger and barrel surface preparation process and material significantly changes the service life of the pump. The plunger and pump barrel are a pair of friction pairs. Studies have shown that the friction coefficient between the plunger and barrel surface material and the sand particles can also affect whether the sand particles will get stuck in the gap between the plunger and the pump barrel. Versailles Versailles Ball wear and tear Eroding Sucker rod connected to the piston through the swimming valve, reciprocating piston piston valve cover makes the load carrying a variable size load asymmetric stress in the valve opening and closing process, continuous Impact caused the valve wall wear and fatigue damage. As the outlet of well fluid, the gas mask is affected by the erosion and erosion due to the change of the direction of the fluid flow, eventually resulting in failure of the fracture. Versaille seat due to long-term fluid and solid erosion, can also lead to sealing surface failure. Piston and pump cylinder clearance The plunger and pump cylinder with the reciprocating movement of the clearance fit. The relative movement of the pump barrel and the plunger relies on the sealing effect of the small clearance between the mating surfaces, and at the same time, this slight clearance ensures that there is always a certain amount of liquid loss between the plunger and the pump barrel for lubrication and cooling. For certain well conditions, the pump gap is an important technical parameter of the pump, the size of the pump gap directly affects the efficiency of the pump, affecting the pump cycle. Downhole tube string partial wear and corrosion due to various factors lead to tubing, sucker rod, centralizer, sucker rod coupling and other wear and corrosion, if wear and corrosion products such as iron slag, tubing coating flaking deposition on the pump , Resulting in card pump and Versail not leak after sealing. Pump hanging deep well pump hanging deepen, will make the pump to withstand the load increases, making the plunger and pump cylinder pressure and friction increases, the fluid on the plunger and pump cylinder hydraulic erosion will also increase Large, coupled with the above other factors, pump failure will speed up. Wellbore structure As the pump cylinder length of about 4-9 meters, if the vertical section of the hanging pump well is not vertical, such as horizontal wells, inclined shafts or dogleg at the cylinder may be deformed or partial contact with the pump cylinder, will Increase the plunger and pump barrel between the local wear and tear. Downhole temperature and pressure downhole temperature have an indirect impact, such as the impact of plunger and pump cylinder corrosion rate, affecting the speed of scaling, and even affect the deformation of the cylinder easy. Can be seen from the above, plunger pump failure due to many reasons, should be based on the specific well to identify the main reasons and take appropriate measures.