Most of the domestic oilfields have entered the high water cut development period, and the conventional plunger pump is one of the main oil recovery methods. Due to factors such as high sand content, high water content, high salinity, high-temperature steam heavy oil exploitation, polymer injection mining and strong corrosive medium environment, the average pumping cycle of plunger pump wells is getting shorter and shorter, and some are not even It takes 30 days to check the pump, which seriously affects oilfield development. According to the failure reasons of the plunger pump, such as oil well water discharge, sand production, injection of corrosive fouling injection, high salinity, bottom hole temperature, corrosion degree of liquid medium, well structure and plunger pump itself The structural incompatibility, the surface treatment of the plunger and the pump barrel, and the surface material cannot meet the requirements. The protection methods of the plunger pump are also various, mainly the following:

Pump structure change

In the sanding oil well, the conventional plunger pump often has the phenomenon of sand stuck plunger, sand buried sucker rod, sanding pump cylinder and plunger, which makes the oil pump fail prematurely. In response to these problems, pump developers have designed long plunger short pump sand control pumps. During the production process, a part of the plunger is always exposed to the pump cylinder, and the sand sinking is not easy to enter the gap between the pump cylinder and the plunger, which can avoid the occurrence of sand card or sand buried plunger accident after stopping pumping, effectively extending the oil well. Free repair period. Some pumps also add some auxiliary components, such as the lower sanding cup, functional joints, etc., in order to further prevent the deposition of sand between the pump barrels.

The self-rotating plunger pump can randomly rotate the plunger in each stroke, constantly changing the contact surface between the plunger and the pump cylinder, so that the circumference of the plunger gradually wears evenly, and the sand or scale is removed from the plunger and the pump barrel. Discharge between them solves the severe positioning wear caused by the accumulation of abrasive materials and the column tripping.

In order to achieve the sand control effect, a gapless sealed oil pump and a piston type oil pump have also been developed.

Improving the shape of the groove on the plunger and the position of the groove can also achieve a certain sand-discharging effect.

According to statistics, the failure of the valve cover on the plunger pump is more prominent, and the failure mode is mainly fracture. There are two occurrences: one is the oil outlet at the upper valve cover; the other is the root of the thread at the connection between the tie rod and the upper valve cover. To this end, a special anti-break valve cover has been specially designed to avoid the upper valve cover breaking when the pump is working.

In order to prevent the loss between the Versailles and the Versailles, some pumps are also designed with multiple swimming Versail and fixed Versailles.

The “vacuum” chamber double plunger pump is used to extract viscous oil and stabilize the viscous oil-water emulsion. It uses the “vacuum” chamber to cause the sucker rod and plunger when the pumping unit is down stroked. The downward force is such that they produce a downward forced motion. Diaphragm pump is used to mine crude oil containing abrasive particles (such as sand and mechanical impurities) and corrosive media. It uses diaphragm to protect the working components of the pump to prevent sand, salt and corrosive. The liquid phase contact of the medium in the medium extends the service life of the pump.

Improvements in pump materials and surface treatment

Generally, the bushing material is 20CrMo carburizing or 38CrMoA nitriding, and also has 45 steel chrome plating, and the plunger is made of carbon steel chrome plating. This kind of coordination pair is not suitable for the environment with high sand content and high salinity medium. From the investigation and analysis of the failure well, the protective layer of the auxiliary pair is easily destroyed under the abrasion of high hardness quartz sand, followed by severe electrochemical Corrosion, causing the protective layer to fall off, and serious accidents caused by the pump. From the actual situation of the current oilfield, the use of nickel-based spray-welded alloy coated plungers has become more common, which can partially solve the above problems, but the effect is still not good for wells with serious sand production or serious scaling. With the advancement of surface treatment technology and material processing technology, new materials and surface treatment processes for plungers and pump barrels will continue to be introduced. At this time, special attention should be paid to the optimal matching of the materials of the plunger and the pump barrel. The special ceramic pump to be launched by Anton Orle Engineering Technology Co., Ltd. will greatly improve the performance of the plunger pump in terms of sand control, anti-scaling, anti-wear and high temperature resistance.

The valve and seat are mostly made of 3Cr13, and a few are 6Cr18Mo and 9Cr18Mo. From the field application situation, the hardness, wear resistance and corrosion resistance are the main reasons for the stab failure and failure of the fixed valve. In the oil field, the tungsten carbide carbide valve seat is used to replace the original 6Cr18M, but it should be noted that the density of the valve ball will increase the oil flow into the pump resistance and the pressure drop at the fixed valve. There are also ceramic Versail balls and ceramic valve seats. Ceramics may sometimes crack and should be used during use.

Pump related tube string structure change

By using an ultra-high-strength sucker rod column and a weighted weight rod at the bottom of the pole column, the bending of the pump barrel can be prevented, and the wear of the plunger and the pump barrel can be reduced.

Processing and manufacturing process

Due to the differences in the processing, material handling, assembly and other aspects of the pump plunger, the various parameters of the pump of the same specification may not be completely consistent, which may cause a variety of unexpected accidents, and quality monitoring should be strengthened during the processing.

Other measures

Such as the use of long-stroke low-stroke parameter matching; choose a well with sufficient liquid supply capacity and in the case of maintaining the same pump efficiency, the sinking of the large pump should be slightly larger than the design of the small pump can also extend the service life of the pump to some extent. .