Study On POK And POK/PA6 Composites For Oil Well Pipe Liner

The use of polymer liners for oil pipelines is a lower cost corrosion protection method,but because conventional high density polyethylene liners cannot meet high temperature conditions.A new type of temperature-resistant and corrosion-resistant polymer material is needed to replace polyethylene,which is used in 100 °C high temperature conditions.As a high polymer material,aliphatic polyketone(POK)has the advantages of low cost,high melting point,good barrier property,oil resistance and water resistance,and has the potential as a lining material for petroleum pipelines.However,its service under the condition of oil well pipe needs further research.In addition,polyamide 6(PA6)has a high melting point and excellent mechanical properties,but its water and acid resistance is poor,and it is limited to petroleum pipe applications.It is also an idea for developing a high temperature resistant lining to improve PA6-related properties.The properties of POK materials as tubing linings is systematically studied in this paper.The basic physical properties of POK materials,including mechanical properties,Vicat softening point,heat distortion temperature and other basic properties are evaluated.The performance of the POK liner was evaluated by laboratory simulation,including the corrosion resistance of various environments under POK liner,and the corrosion resistance of the simulated working condition.The performance with the POK liner is evaluated by the actual field.The POK material resistant to hydrolysis and it can improve the corrosion resistance of PA6.In this paper,the structure and corrosion resistance of POK/PA6 and POK/EPDMMA(ethylene propylene diene monomer grafted maleic anhydride)/PA6 composite system is systematically studied.The composite of POK and PA6 has excellent mechanical properties,high strength(76.0 MPa)and high elongation at break(184%).With the increase of POK content,the tensile strength of POK/PA6 composites after acid,alkali and water corrosion increases.EPDM-MA first reduces and then increases the melting point of the composite,reducing the crystallization temperature of the composite.The addition of EPDM-MA improves the elongation at break of the composite acid and water after corrosion,but in the alkaline environment,there is no significant increase.