Corrosion Behaviors and Aging Mechanisms of Carbon Fiber‐Reinforced Bismaleimide Resin Composite Pipe in Harsh Wellbore Environments

ABSTRACT Confronting the ever more stringent demands for oil and gas transportation, the development and application of non‐metallic pipes have become increasingly crucial and of strategic importance. In this study, a new carbon fiber‐reinforced bismaleimide resin composite pipe with winding angles of [±85°/±20°/±85°] ₁₁ was prepared. The corrosion behaviors and aging mechanisms of CFRP pipe were analyzed and discussed by simulating harsh wellbore environments. After exposure to single working conditions, the resin matrix exhibits no significant degradation, the fiber‐resin interfaces remain intact without debonding, and the glass transition temperatures (T _g ) of the CFRP pipes remain above 230°C. Following corrosion under continuous alternating condition, the propagation of microcracks and micropores leads to an increase in porosity from 0.78% to 0.96%. However, the internal structure of the CFRP pipe remains intact, the fiber‐resin interfaces show no signs of debonding, and the degradation of resin matrix reduces the T _g to 221°C. Furthermore, the moisture diffusion coefficient of the CFRP pipe in the 150°C hot and humid environment is 7.22 × 10 ⁻¹¹ m ² /s. The results indicate that the resistance of the CFRP pipe to corrosion damage dominated by physical damage with chemical damage playing a secondary role determines its service performance.