Effect of Jet Impingement Velocity and Angle on CO2 Erosion-Corrosion with and without Sand for API 5L-X65 Carbon Steel.

Ihsan Ulhaq Toor,Rached Ben-Mansour,Hassan Mohamed Badr,Zakariya Alashwan,Siamack A Shirazi

doi:10.3390/ma13092198

Abstract

Most oil and gas production wells have plenty of corrosive species present along with solid particles. In such production environments, CO2 gas can dissolve in free phase water and form carbonic acid (H2CO3). This carbonic acid, along with fluid flow and with/without solid particles (sand or other entrained particles), can result in unpredictable severe localized CO2 corrosion and/or erosion–corrosion (EC). So, in this work, the CO2 EC performance of API 5L X-65 carbon steel, a commonly used material in many oil and gas piping infrastructure, was investigated. A recirculating flow loop was used to perform these studies at three different CO2 concentrations (pH values of 4.5, 5.0, and 5.5), two impingement velocities (8 and 16 m/s), three impingement angles (15°, 45°, and 90°), and with/without 2000 ppm sand particles for a duration of 3 h in 0.2 M NaCl solution at room temperature. Corrosion products were characterized using FE-SEM, EDS, and XRD. The CO2 EC rates were found to decrease with an increase in the pH value due to the increased availability of H+ ions. The highest CO2 erosion–corrosion rates were observed at a 45° impingement angle in the presence of solid particles under all conditions. It was also observed that a change in pH value influenced the morphology and corrosion resistance of the corrosion scales.

Highlights

In most oil and gas production environments, it is very difficult to avoid the presence of corrosive species and solid particles
Formation of carbonic acid (H2 CO3 ) in free phase water brings down the solution pH and can result in severe localized CO2 erosion–corrosion [5]
Most facilities dealing with CO2 gas are experiencing CO2 erosion–corrosion issues in their assets, mostly made of carbon steel and low alloy steels [4,6,7]

Summary

Introduction

In most oil and gas production environments, it is very difficult to avoid the presence of corrosive species and solid particles. Used sand screens in oil and gas production wells cannot filter sand particles below 50 μm [1,2,3]. Carbon dioxide gas can dissolve in free phase water and form carbonic acid (CO2 + H2 O ⇔ H2 CO3 ). Formation of carbonic acid (H2 CO3 ) in free phase water brings down the solution pH and can result in severe localized CO2 erosion–corrosion [5]. Most facilities dealing with CO2 gas are experiencing CO2 erosion–corrosion issues in their assets, mostly made of carbon steel and low alloy steels [4,6,7]

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