Quantification of Mechanical Damage in Erosion-Corrosion Degradation of X65 Pipeline Materials Using Acoustic Emission Technique

摘要

As oil and gas wells are aging with exploration and production activities moving towards offshore and deep waters, industry strives to have online, real-time and cost effective methods to predict and monitor erosion-corrosion damage of pipelines so as to operate safely and prevent unplanned production outages. Conventional methods such as failure records, visual inspection, weight-loss coupon analysis, etc can be time consuming and may not detect the onset of sand production which exacerbates erosion-corrosion. Mechanical erosion and its synergistic effect, when in conjunction with pure electrochemical corrosion rate can be significant. In this study, an online, real-time and non-intrusive acoustic emission (AE) technique has been implemented to characterize and quantify the mechanical erosion damage aspect of erosion-corrosion degradation of X65 pipeline material in submerged jet impingement system using circular specimens. The behaviour of the X65 specimens in non-corrosive environment (tap-water saturated with Nitrogen) with different flow velocities (5,10,15 m/s, in the presence and absence of solid particles) was studied for single impingement and multiple impingement conditions at 50oC constant operating temperature and 90o impingement angle. In single impingement test, it was found that the kinetic energy of the impacting particle is direct proportional to the acoustic energy and RMS value as expected with particle and process background noise signals clearly separated in the measured waveform. The time analysis of the multiple impingement test result shows that the acoustic energy increases with increase in flow velocity and sand loading; which signifies that it can be used as a parameter to quantify mechanical erosion damage of the X65 material as well as the overall energy of impacting particles.