Failure Analysis of Steel Wire‐Reinforced Composite Pipes for Gas Field Flowback Fluid

ABSTRACT To clarify the failure mechanism of steel wire‐reinforced thermoplastic (SWRTP) pipes in flowback fluid pipelines, failed and intact samples were systematically investigated. Compression cracking and hydraulic burst tests confirmed the original intact pipe met standard requirements. The failed pipe exhibited circumferential cracking near the metal joint, displaying environmental stress cracking (ESC) characteristics. Morphological and spectroscopic analyses revealed complex electrochemical corrosion of the steel wires driven by CO 2 , HCO 3 − , and SO 4 2− species from the penetrating fluid. Furthermore, thermal analysis showed a localized oxidation induction temperature (OIT) decrease at the fracture surface (209.84°C), suggesting but not definitively proving service‐induced antioxidant depletion. The failure is proposed to be ESC, possibly attributed to metal‐joint crimping stress and the flowback chemical environment synergistically degrading the resin matrix. Crucially, it is hypothesized that antioxidant depletion and crack propagation mutually accelerated localized polymer embrittlement. Subsequent fluid ingress caused severe electrochemical corrosion of the steel wires, drastically reducing the pipe's pressure‐bearing capacity and ultimately leading to inside‐out penetrating cracks.