Electrochemical Modelling and Experimental Approach to Steel Casing Design

Abstract

Casing integrity is a critical requirement to the long-term performance of oil and gas wells. Casing materials and design are affected by various well conditions such as the type of drilling and production fluids and the type of formation the well is drilled into. Several casing failures were reported in ADNOC onshore oil wells, and an in-depth analysis showed that the failures are mainly corrosion induced. However, the root causes and the mitigation methods for the failures were not well established. In this study, an in-depth literature review was conducted to identify key knowledge gaps in casing steel design and corrosion modeling. Then, a comprehensive experimental program was designed to assess corrosion behavior of typical casing steels (P110 and L80) under various operating conditions. The influence of steel microstructure, presence of aggressive ions such as Cl-, S2-, HCO3-, CO2, and O2 on corrosion behavior were studied. Finally, electrochemical modeling was carried out using COMSOL Multiphysics to provide a comprehensive view on the corrosion and protection processes of casing steels. A protective strategy is proposed to reduce corrosion rates based on a novel synthesized corrosion inhibitor.

Date of Award	22 May 2025
Original language	American English
Supervisor	Akram Alfantazi (Supervisor)