Hydrostatic Experimental Study and Failure Mechanism of Glass Fiber Reinforced Thermoplastic Pipes Used for Oilfields

The traditional carbon steel pipe has been unable to meet the needs of high corrosive media oil and gas production since the gradual increase of the moisture content, and the increasingly severe corrosion environment during the deepening of the oil and gas field development process. In such situation, the reinforced thermoplastic pipe, as a typical non-metallic pipe, has become important solution for corrosion protection, and used in oil and gas gathering and transportation widely. In this study, the residual strength of reinforced thermoplastic pipe for oil and gas gathering and transportation was studied by using hydrostatic pressure residual strength method based on linear regression using pressure composite device with inner lining of PVDF and reinforced layer of glass fiber reinforced resin tape. The damage mechanism of the flexible composite pipe was studied by means of scanning electron microscopy. The results showed that the residual strength of the flexible composite pipe decreased with the increase of service time, and the logarithmic value was linear with the service time. The damage mechanism of the reinforcement layer was similar to that of the composite material, which was composed of four stages: matrix cracking, crack propagation, delaminating and fiber fracture.