1. Analysis of the causes of corrosion of rod pump barrels：
Rod pump barrels corrosion is mainly due to complex underground media：
One is that the chloride ions and sulfate ions contained in the highly mineralized formation water will destroy the passivation film on the metal surface of rod pump barrels and cause electrochemical corrosion; The other is that the acid gases such as hydrogen sulfide and carbon dioxide contained in crude oil combine with water to form an acidic solution, which will cause chemical corrosion on the inner wall of rod pump barrels; The third is that the metabolites of underground bacteria (such as sulfate reducing bacteria) will accelerate the corrosion reaction, especially in low temperature and hypoxic environments. The corrosion rate is significantly increased.
Preventive maintenance strategy：
The choice of corrosion-resistant materials is the core. The rod pump barrels supporting Dongsheng Petroleum's rod pump barrels use specific corrosion-resistant alloys, and the inner wall is nitrided to form a wear-resistant layer, which can effectively resist the erosion of acidic media and highly mineralized water. At the same time, Dongsheng Petroleum's customized corrosion inhibitors (which are extremely compatible with rod pump barrels) are regularly injected into the borehole, and the inner wall of rod pump barrels is regularly tested (recommended once every 3 months) to control the corrosion rate at a low level.
2. Analysis of the causes of fouling of rod pump barrels：
Fouling is mostly due to imbalances in the composition of downhole fluids: First, the calcium and magnesium ions in the formation water combine with carbonate and sulfate ions to precipitate when the temperature rises (more than 60℃) and the pressure drops to form calcium carbonate and calcium sulfate scale; Second, the asphaltene and colloids in crude oil attach to the inner wall of rod pump barrels and mix with minerals to form composite scale; Third, if there are impurities in the gap between the rod pump barrels pump piston and the pump cylinder, it will become the “core” of the scale attachment, accelerating the accumulation of scale.
Preventive maintenance strategy：
To control fouling from the source, Dongsheng Petroleum chelated antifouling agent can be injected, which can form a stable complex with calcium and magnesium ions and inhibit the formation of scale; At the same time, the inner cylinder of Dongsheng Petroleum rod-type rod pump barrels is coated with nano ceramics, the surface roughness Ra≤0.2µm, and the adhesion of the scale body is reduced by 60%. Even a small amount of fouling can fall off during the reciprocating movement of the piston. In addition, it is recommended to use Dongsheng Petroleum's high-pressure well washing equipment (suitable for its full range of rod pump barrels pumps) to clean the well shaft every six months to avoid dirt clogging the inlet channel of the pump shaft.
3. Analysis of the causes of wear of rod pump barrels：
Wear mainly comes from mechanical friction and impurity impact: First, during the reciprocating movement of the sucker rod, it will produce partial wear with the inner wall of the rod pump barrels, especially in deep wells, the bending of the well body will intensify the contact wear; Second, the sand particles and impurities in the formation output fluid will scour the inner wall of the rod pump barrels and the inlet of the pump barrel with the flow of fluid, causing erosion and wear; Third, if the concentricity deviation of the rod pump barrels is large when the pump is installed, it will cause abnormal friction between the piston and the pump barrel, which will accelerate wear.
Preventive maintenance strategy：
The selection of high-wear-resistant products is the key. The pump barrel of Dongshengshi rod pump barrels adopts the overall forging process, the cylinder wall hardness is higher, and the wear resistance is greatly improved than that of ordinary pump barrels; The inner cylinder of the rod pump is equipped with a cemented carbide guide ring, which can reduce the damage of partial wear of the sucker rod to rod pump barrels. At the same time, Dongsheng Petroleum's sand-proof filter device is installed at the entrance of rod pump barrels, which can effectively block the entry of sand particles; Dongsheng Petroleum's special centering tool is used during installation to reduce abnormal wear and tear.
4. Comprehensive maintenance：
In addition to responding to the three major problems in a targeted manner, a comprehensive maintenance system needs to be established: The Dongsheng petroleum well shaft inspection system is used regularly (every 1-2 months) to detect the wall thickness of rod pump barrels and the wear of the pump barrels through ultrasonic waves; The pumping parameters are adjusted according to the well conditions to avoid additional losses caused by overloaded operation; For aging rod pump barrels and pump barrel components, priority is given to replacing Dongsheng Petroleum's original parts to ensure the matching of materials and sizes, and avoid exacerbating failures due to incompatible parts. Through the “prevention + detection + adaptation and replacement" mode, the average service life of rod pump barrels and pump barrels can be extended, significantly reducing mining costs.