Abstract

This PhD research investigates the aging behavior of Polyetheretherketone (PEEK) when exposed to supercritical CO₂ and acidic environments at elevated temperatures, conditions commonly encountered in the oil and gas industry, specifically downhole applications. With growing interest in replacing traditional carbon steel components, PEEK presents a promising alternative due to its superior chemical resistance, thermal stability, and mechanical properties, resulting in reduced maintenance in oil and gas operations. The study evaluates the long-term performance of PEEK under these harsh conditions through their impact on mechanical, physical and thermal properties.

The findings demonstrate that PEEK offers significant stability when exposed to supercritical CO₂ and acidic environments at elevated temperatures. Effects of both environments on microstructure and chemistry are elucidated. Phenomena, such as secondary crystallization, are observed while very limited. Mechanical quantities of interest, such as elasto-plastic and fracture properties feature also limited modifications. Finally, the study also delves into the long-term performance of 3D-printed PEEK, which is more popular for the rapid prototyping of replacement parts for various industrial components.

This research contributes valuable insights for the oil and gas industry, promoting the adoption of PEEK as a viable replacement for carbon steel in applications where long-term material resilience is critical, particularly in CO₂ transport and well treatment processes.