The sucker rod is a slender, critical component of the pumping unit in oil wells. It connects the polished rod at the surface to the downhole pump, transmitting mechanical power to operate the pump. Typically, each individual sucker rod has a length of 7.62 meters, 8 meters, or 9.14 meters, and is made from low-carbon alloy steel that undergoes quenching and tempering treatment for enhanced strength and durability. These rods are joined together using internal-thread couplings and extend deep into the wellbore, often reaching depths of over two kilometers. In some cases, like in the Shengli Oilfield, the depth can exceed three thousand meters.
During operation, the sucker rod string experiences cyclic loading due to the reciprocating motion of the pump. The working environment includes well fluids such as crude oil and formation water, which may contain corrosive elements. As a result, fatigue and corrosion fatigue fractures are common failure modes. When a sucker rod breaks, it leads to production downtime, increased maintenance costs, and higher overall operating expenses.
Sucker rods have been in use for nearly a century. Initially, they were made from natural materials like rattan. The first metal sucker rod patent (U.S. 528168) was granted to Samuel M. Jones in Ohio on October 30, 1894. Over the past two decades, significant advancements have been made in their design and manufacturing. New materials like multi-element alloy steel and fiberglass are now used. Advanced technologies include forging with intermediate frequency induction heating, infrared temperature measurement, non-rotating head production lines, and automated coupling systems. Processes such as external thread rolling, variable diameter elbows, friction welding, shot peening, and surface hardening have greatly improved product quality and performance.
To meet the demands of various challenging well conditions—such as large pump operations, deep pumping, heavy oil, high wax content, and corrosive environments—specialized sucker rods have been developed. These include ultra-high-strength rods, FRP (Fiberglass Reinforced Plastic) rods, hollow rods, KD-grade rods, continuous rods, electrically heated rods, wire rope rods, and aluminum alloy rods. Alongside these, many accessories have been designed to enhance the performance and longevity of the rod string, such as long-stroke polished rods, toothless clamps, rotating devices, shock absorbers, graphite sealing boxes, roller couplings, centralizers, wax scrapers, weighted rods, anti-drop devices, and magnetic anti-waxing tools.
**Technical Principle**
The high-strength sucker rod coupling is designed to provide excellent tensile performance. The coupling size is typically 5/8", matching or exceeding the performance of the rod itself. To prevent electrochemical corrosion caused by wear, sacrificial anode protection is employed. This method uses an anode body connected through an electrolyte to supply cathodic current to the protected structure, offering long-term corrosion resistance. To prevent the anode from being eroded by fluid flow, stainless steel sheaths are installed around the rod joints and the anode. Additionally, the coupling is made from high-nickel alloy, ensuring a smooth surface that significantly extends the life of the coupling.
**Technical Parameters**
- Size: 1", 7/8", 3/4", 5/8"
- Supporting Rod Diameter: 25mm, 22mm, 19mm, 16mm
- Centralizer Outer Diameter: Up to φ56mm
- Sacrificial Anode Protection Range: 50m
- Effective Power Generation: ≥1.1 A.h/g
- Anode Consumption Rate: ≤12.36 kg/A.a
- Current Efficiency: ≥65%
**On-Site Installation**
When installing the sucker rod, it should be connected using the appropriate threaded couplings. The installation section should be determined based on the degree of corrosion and eccentric wear in the well. A sacrificial anode device is typically installed every 80–100 meters. For optimal performance, it is recommended to use this system in conjunction with the KXY-2 tubing cathodic protector and standard nylon centralizers. This combination enhances the effectiveness of corrosion and wear protection, ensuring longer service life and better reliability in harsh well conditions.
CB-840S is an Adhesion Promoter made by high-performance modified Chlorinated Polypropylene Resin. It is based on a special chlorinated polypropylene resin. By adjusting the molecular weight and modifying it with other resins, CB-840S greatly improves its adhesion on non-polar materials such as PP/OPP/BOPP; it can also better improve its adhesion on polar materials such as ABS/PET/aluminum foil.
CB-840S is a transparent liquid with ethyl acetate as the main solvent. It has good compatibility with chlorinated polypropylene resin, Polyurethane Resin, polyketone resin, rosin resin, etc. It can also be mixed with a small amount of acrylic resin, CAB Resin, chlorine and vinegar resin. For solvent-based inks and coatings, the generally recommended addition amount is 0.3%-1%.CB-840S can be added after grinding.
CB-840S Adhesion Promoter, Polyurethane Resin, Adhesion Promoter, CAB Resin
Guangzhou Chengbian Chemical Technology Co., Ltd. , https://www.gzcbct.com