First, the oil field water injection wells higher water pressure, pump pressure up about the moment may exceed the rated pressure of the pump, the pump is always in high load operation; Second, injection of sewage, poor water quality, strong corrosive, high water temperature , Easy to cause damage to the valve body, valve, pump head, packing assembly and other vulnerable parts, so that the pump is in a high opportunity to damage the state; Third, maintenance personnel regular maintenance, replacement parts, the pump is not continuous work status. Pump running status does exist some worries, to analyze the causes of some common pump failures, and to make timely diagnosis and monitoring diagnosis system to make judgments and prevention, both from a security point of view or from the economic aspects are particularly important. Pumping pump condition analysis The basic structure is: the crankshaft, connecting rod, crosshead and other components of the power end; by the pump head, valve, plunger and seal device composed of hydraulic end, in addition to cylindrical, spherical nitrogen stability Pressure regulator and safety valve. The hydraulic end of the horizontal straight through the combination of the overall structure of the pump head. Work, when the plunger moves backward, the outlet valve is closed, while the suction valve is open, start absorbing process; When the plunger forward movement, the suction valve is closed, the valve is opened at the same time. This cycle, continue to absorb water, drainage. Water Pump Overview. Since the pump was put into operation, with the increase of running time, the aging of various components one after another, the original working conditions have undergone great changes. First of all, as the development of the oilfield requires the continuous improvement of water injection strength, the pump pressure is also on the rise. At present, some of the operating pressures have reached or exceeded the rated pressure of the water injection pump. For these overpressure operation of the water pump easily lead to equipment safety incidents. Secondly, fatigue damage may occur to the moving parts of the water injection pump. Because the water injection pump belongs to the reciprocating piston pump, the five crankshaft connecting rod shoes and the crankshaft bearing cyclical heavy load act as the number of operating hours increases. Easy to appear off pieces, crankshaft journal wear and so on. Again, the water pump increases the gap between the movement, due to the long hours of operation, the crosshead and crosshead copper sleeve, connecting rod tile and small head tile will exacerbate wear and tear, increased gap leading to increased pump vibration, oil temperature, Pump operation noise is also significantly increased. The current crankcase oil temperature has risen to around. ã€Influence of Sewage Water Quality on Water Injection Pump】 Sewage separated from oil during the dehydration of crude oil is separated by oil-water separation, deoxidized, and sterilized before being injected into the oil layer. Although treated to a certain extent, the injected water is still oil-bearing (polymer) sewage, which is generally alkaline, has low hardness, low iron content, high salinity and low water quality compliance rate. Due to the repeated use of sewage, Its suspended solids, artificial additives, etc. will be relatively high, widespread corrosion, scaling and plugging and other issues, of which the greatest damage to corrosion. Combined with the special geographical environment of the oilfield (saline-alkali and marsh area), reservoir characteristics (low-porosity and low-permeability condensate reservoir) and characteristics of output fluids (high salinity), various metal pipelines and equipment Corrosion is more serious, especially the joint station oily sewage treatment system corrosion is more prominent, put into operation two months on the emergence of equipment corrosion perforation, seriously affected the normal production. Water quality corrosion of water injection pump components: When using a water injection pump to transport sewage media, the minerals and additives tend to precipitate on the sealing device, reducing the sealing effect. The solid particles can also cause excessive wear on the sealing device. Water injection pump leakage increases, shortened life expectancy, so the sewage quality is the main reason for the failure of the plunger pump seal. From the pump room operation shows that the injection of water two pumps are particularly serious corrosion, not only for the pump itself, the water quality will also corrode other water injection facilities, such as the pipeline connected to the perforated phenomenon. Corrosion reason can be attributed to the following aspects: (1) dissolved oxygen in water of high salinity, dissolved oxygen plays a role of cathode depolarization in the corrosion process, and the corrosion of steel is intensified by the sewage. (2) sulfate-reducing bacteria and hydrogen sulfide wastewater contain a large number of sulfate-reducing bacteria, which have a greater impact on the local corrosion of steel. (3) When the content of suspended solids and oily oil is large, they stick together and adsorb and deposit on the inner wall of the system, resulting in conditions that are more conducive to the growth and reproduction of sulfate-reducing bacteria. At the same time the dirt will increase the adsorption of germicides, bactericidal effect worse, to promote bacterial corrosion. Dirt deposition on the steel surface, the lower the potential to become the anode, in the absence of dirt at the cathode, the formation of scale corrosion. Field often use infrared temperature detector on the pump hydraulic cylinder temperature detection, and the injection of sewage pump prone to over-temperature conditions, because the sewage itself is too hot, the heat is large, if the heat is not easy to cause packing and packing Abnormal wear between the plunger to speed up the packing replacement frequency; but also lead to a gradual increase in oil injection pressure, resulting in increased water injection energy consumption. ã€Common Fault Analysis and Solution of Water Injection Pump】 Cylinder temperature rise and solution: Cylinder temperature rise is a common failure on the power side. As mentioned above, the crankcase oil temperature has been greatly increased. Mainly due to the increase in water pump operating hours, the various parts of the cyclical cyclical load caused by serious, there are: Bearing serious wear and tear, crankshaft wear, lubricant emulsification or viscosity decline, the power side of the phenomenon of partial wear (such as crank limp Grinding), even more serious changes in trajectory connecting rod, crankshaft fixed bearing wear and so on. In addition, when the pump valve loosening phenomenon, some components may fall into the pump cylinder, which will result in decreased sealing performance. Seal failure (usually packing damage), connecting rod serious leakage of thorns, the seal must be replaced immediately. Otherwise, the water will enter the crankcase along the connecting rod to emulsify the oil, resulting in severe damage to the power end (especially the crankshaft) and even the entire pump in a short time. As the crosshead in the slide constantly back and forth movement, prone to the slide injury, etc., in serious cases will cause the pump shell scrapped, even if it can be repaired, because this type of pump is the integration of the pump casing Design, so the repair is equal to the entire pump overhaul. It is understood that the station has been scrapped - a pump casing (each value & million multivariate), and to be overhaul to be transported to the Dagang Oilfield, freight, maintenance costs and other costs are quite high. The solution is to promptly replace parts, lubricants and calibration. Seal packing leakage reasons and analysis: Injection pump plunger sealing more with soft asbestos packing for sealing, on the one hand these types of materials easily damaged, as mentioned above water quality causes the packing is corroded, or even Fracture, etc., the need to constantly replace the filler; the other hand, due to the high pressure medium in the delivery state, the plunger movement abnormalities can lead to uneven packing force, resulting in the phenomenon of media leakage; In addition, packing gland due to run Over time will appear too loose phenomenon, resulting in seal leakage. The solution is to repeatedly replace the packing when the final shape; in order to prevent uneven force, pressure and pressure required, and measured with a torque wrench; routine maintenance need to adjust the gland tightness. ã€Reasons for Failure of Plunger Seal】 Due to the long service life of water injection pump, poor weather conditions in the oil zone and serious corrosion caused by the quality of effluent water on the plunger, the surface of the plug gradually becomes unnoticeable to the naked eye The trenches and pits generate a little bit. More tiny waterways. The minor erosion of the plunger surface and the failure of the packing are the main causes of the plunger seal leakage. The aqueous medium also drips into the piston chamber through the plunger seal under the effect of internal high pressure. In addition, the scaling will have an impact on the seal, the sewage contains calcium and magnesium ions and carbonate ions, easy to produce carbonated scale. When the plunger pump is out of service, there is sewage between the plunger and the seal. When the water evaporates, crystals are precipitated. When the plunger is replaced or overhauled, white crystals are attached on the surface, which will cause the plunger pump to run Hard wear, resulting in seal failure. Pump body and pipeline vibration reasons and analysis: From the scene of the pump operation point of view, the vibration of the pump body is more serious, feel more strongly by hand touching the pipeline, observe the installation of thermometers and other meters on the pump body is also not Steady state, the buried pipeline pump cement cracks also appeared many times, and again the scene of high intensity noise and vibration have a great relationship and so on. After investigation and analysis, the general reasons are summarized as follows: (1) The foundation is not strong. (2) A large cylinder or a few large hydraulic losses, resulting in uneven pressure on the pump head. (3) crankshaft axial movement. (4) Plunger connection clip loose. (5) crankcase internal failure and so on. Summary: Pump in operation, in addition to wearing parts need to replace the normal wear and tear repair, the most important is to avoid the internal crankcase failure, this failure may cause burning tile, pulling cylinder phenomenon, resulting in equipment operation accidents, serious When the equipment is completely scrapped. The reasons for burning tiles are many, there are: the viscosity of oil failed to meet the requirements; the presence of impurities in the oil; emulsified oil and other water. Of course, crankshaft and bush clearance is too large or too small; crankshaft axial bearing clearance is too large or too small; connecting rod deformation, etc., may also cause internal crankcase failure.