Nylon Centralizer VS UHMWPE Centralizer
Composite material centralizer for sucker rod used in drilling well of oilfield, water, gas, chemicals, and line fixture. TFP plastic centralizer has many advantages, such as: high lubrication, much lower coefficient of friction, non-metallic, non-corrosion,impact resistance, high durability,light weight, and easy to install, etc.
Nylon is the most widely used polymer material for the manufacture of centralizer. Nylon centralizer serves the defects of metal roller centralizer and has obvious advantages: Nylon material has good mechanical strength, strong impact and corrosion resistance, excellent wear resistance and corrosion resistance.
The pure nylon centralizer is installed on the tubing hoop or stuck on the sucker rod after the injection molding. Because of the strong characteristics of the molecular structure of nylon, the water absorption rate is high. Therefore, its strength and modulus are easy to decrease, which affects the dimensional stability. Meanwhile, nylon centralizer’s strength at low temperature is not very good, and its creep resistance needs to be improved, which make heat resistance and wear resistance limited. Moreover, the friction factor of nylon to steel in water lubrication environment is higher than that in dry environment, and the wear resistance is seriously influenced. All of these greatly reduce the service life of nylon centralizer in waterflooding oil fields. As for these problems, composite reinforcement modification approach to improve: Glass fiber (GF) reinforced nylon, carbon fiber reinforced nylon, glass fiber composite reinforced nylon.
Ultra high molecular weight polyethylene (UHMWPE) has a molecular weight of more than 1.5 million, with unparalleled wear resistance, impact resistance, corrosion resistance, low temperature resistance, self-lubricating, anti-adhesion, no water absorption and other comprehensive properties, etc. UHMWPE is known as "amazing plastics."
The UHMWPE centralizer used for sucker rod in oil field is formed by injection molding. It has strong wear resistance, anti-corrosion, , anti-low temperature, anti-lubrication, anti-adhesion and non-absorbency, so as to overcome the defects of nylon, such as: water absorption and swelling, hydrolysis, brittle at low temperature, fragile and large frictional resistance, etc. The test results show that the service life of UHMWPE centralizer is much longer than that of traditional nylon centralizer.
With the development of modification and manufacturing technology of polymer composites, many equipment in the rod pump oil recovery system are gradually replaced by some composite materials. The advanced composite material is widely used in the rod pump oil recovery system with more complex environment. The main advantages are as follows: high mechanical strength, strong corrosion and aging resistance, good wear resistance, convenient construction, high efficiency and low operating cost.