Characterisation of CO2 corrosion scale in simulated solution with Cl– ion under turbulent flow conditions

Abstract In the present work, characterisations such as surface morphology, cross-section image and composition of corrosion scale formed on the P110 steel under turbulent flow conditions with various Cl– concentrations have been studied by means of scanning electron microscopy, X-ray diffraction and X-ray photoelectron spectroscopy. The corrosion medium was the simulated solution of one oil/gas field, saturated with CO2 at 100°C and 4 MPa. The tests were conducted corresponding to various Cl– concentrations and varied flow velocities. It is concluded that Cl– concentration and flow velocity have an important effect on the corrosion scales formed on the samples. In addition, the protective properties and adherence of the corrosion scales were characterised by the analysis of the scale formation and influence mechanisms associated with Cl– concentration and flow velocity. Moreover, a lattice model is created to interpret and illuminate the corrosion process.