In oil extraction operations, rod pump barrels is the core component of the tubing pump, and the operating status directly determines the oil recovery efficiency and operating cost. Once rod pump barrels fail, it will not only cause oil production to be interrupted, but may also cause complex underground problems, increasing the difficulty of maintenance and economic losses. Therefore, mastering the fault diagnosis method and scientific maintenance strategy of rod pump barrels is essential to ensure the stable development of oil extraction operations.
Ⅰ. Common fault types and diagnosis methods of rod pump barrels：
1. Wear failure and diagnosis：
Wear is the most common failure of rod pump barrels, mainly due to the long-term reciprocating friction between the inner wall of the pump barrel and the plunger, as well as the scouring of underground sand-containing and impurity fluids. After rod pump barrels are worn out, there will be a decrease in oil production and unstable wellhead pressure.During diagnosis, the wellhead holding pressure test can be used: close the wellhead oil outlet valve, start the pumping unit, and observe the pressure rise speed and the maximum pressure value. If the pressure rises slowly and the maximum value is lower than the normal range, combined with the abnormal noise of the pumping unit, the wear of rod pump barrels can be preliminarily judged; you can also directly observe whether there are scratches, pits or dimensions on the inner wall of rod pump barrels through underground video testing equipment to confirm.
2.Corrosion failure and diagnosis:
The underground contains corrosive media such as hydrogen sulfide and carbon dioxide, which can easily cause corrosion of rod pump barrels due to long-term effects. After rod pump barrels corrode, the inner wall will peel off and perforate, which in turn causes leakage and reduces the pumping efficiency.When diagnosing, first analyze the composition of the wellhead output fluid and detect the content of corrosive media. If the standard is exceeded, focus on investigating the corrosion of rod pump barrels; At the same time, monitor the current of the pumping unit. If the current fluctuates abnormally and the wellhead liquid production is reduced, combined with downhole sampling and metal debris is found, the corrosion of rod pump barrels can be judged; during regular pump inspections, if the surface of rod pump barrels is observed to have rust, spots or local thinning, the corrosion failure can also be confirmed.
3.Card pump failure and diagnosis:
The failure of the stuck pump is mostly due to the entry of foreign objects (such as falling objects, fouling, wax plugging) in the rod pump barrels, or the abnormal gap between the pump barrel and the plunger. When rod pump barrels are stuck in the pump, there is a chance that the load on the donkey head will increase sharply, the operation will be stuck or even unable to operate.During diagnosis, the suspension point load of the pumping unit can be measured. If the load is far beyond the normal range and the current rises sharply, combined with the absence of liquid output at the wellhead, the pump can be preliminarily judged; the use of downhole acoustic wave detection technology can detect whether there is a foreign body clogging in the rod pump barrels; If the pump inspection finds that the plunger is stuck in the pump barrel, or there is obvious fouling and waxy accumulation in the pump barrel, it can be diagnosed.
Ⅱ. Scientific maintenance strategy of rod pump barrels:
1. Regular testing, early warning：
Establish a regular inspection system for rod pump barrels, and formulate the inspection frequency according to underground working conditions and mining cycles. Daily use of wellhead pressure monitoring, current monitoring, liquid production statistics and other means to grasp the operating status of rod pump barrels in real time; conduct wellhead pressure holding test and current data analysis once a month, and conduct downhole video or acoustic wave detection once a quarter to detect hidden dangers in time. At the same time, data analysis technology is used to analyze the trend of rod pump barrels operating data, establish a fault early warning model, and timely warn and arrange maintenance when the data is abnormal.
2.Improve working conditions and reduce damage：
In view of the problems of underground corrosive media and sand content, targeted measures have been taken to improve working conditions and reduce damage to rod pump barrels. Oil wells with high sand content can install desanding devices at the wellhead to reduce the content of sand particles entering rod pump barrels; Corrosion inhibitors are injected underground to inhibit the corrosion of rod pump barrels by corrosive media. In addition, the operating parameters of the pumping unit are rationally adjusted to control the reciprocating speed and stroke of the plunger to avoid exacerbating the wear of rod pump barrels; According to the amount of liquid produced in the oil well and the nature of the fluid, choose the appropriate rod pump barrels material, such as stainless steel rod pump barrels in high-corrosion environments to improve corrosion resistance.
3.Standardize maintenance and extend life：
When rod pump barrels fail to repair, they must be operated strictly in accordance with the standardized process to avoid secondary damage. Operate the lifting equipment smoothly when lifting the pump to prevent rod pump barrels from colliding and deformation; After disassembly, thoroughly clean the rod pump barrels to remove impurities, fouling and waxy on the inner wall, and carefully check the degree of wear and corrosion.Lightly worn rod pump barrels can restore their performance through inner wall repair techniques such as chrome plating and spraying of wear-resistant coatings; If the wear and corrosion are serious, or there are perforations or cracks, new rod pump barrels need to be replaced in time. When replacing, ensure that the gap between the new pump barrel and the plunger is up to standard, and seal it during installation. After the repair is completed, the wellhead pressure test and trial operation will be carried out to confirm that the rod pump barrels are operating normally before they can be put into use.
As a key component of oil extraction, rod pump barrels' fault diagnosis and maintenance directly affect the efficiency and cost of oil recovery. By accurately identifying faults such as wear, corrosion, and stuck pumps, and adopting strategies such as regular testing, improving working conditions, and standardizing maintenance, rod pump barrels can effectively reduce the incidence of failures, extend their service life, and ensure the continuous and stable progress of oil extraction operations. In actual operations, it is necessary to continuously improve the diagnosis and maintenance plan based on the specific working conditions of the oil well to provide a guarantee for the reliable operation of rod pump barrels.