Effect of CO2 Partial Pressure on the Corrosion Inhibition of N80 Carbon Steel by Gum Arabic in a CO2-Water Saline Environment for Shale Oil and Gas Industry

Gaetano Palumbo,Kamila Kollbek,Roma Wirecka,Marcin Górny,Andrzej Bernasik

doi:10.3390/ma13194245

Abstract

The effect of CO2 partial pressure on the corrosion inhibition efficiency of gum arabic (GA) on the N80 carbon steel pipeline in a CO2-water saline environment was studied by using gravimetric and electrochemical measurements at different CO2 partial pressures (e.g., = 1, 20 and 40 bar) and temperatures (e.g., 25 and 60 °C). The results showed that the inhibitor efficiency increased with an increase in inhibitor concentration and CO2 partial pressure. The corrosion inhibition efficiency was found to be 84.53% and 75.41% after 24 and 168 h of immersion at = 40 bar, respectively. The surface was further evaluated by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), grazing incidence X-ray diffraction (GIXRD), and X-ray photoelectron spectroscopy (XPS) measurements. The SEM-EDS and GIXRD measurements reveal that the surface of the metal was found to be strongly affected by the presence of the inhibitor and CO2 partial pressure. In the presence of GA, the protective layer on the metal surface becomes more compact with increasing the CO2 partial pressure. The XPS measurements provided direct evidence of the adsorption of GA molecules on the carbon steel surface and corroborated the gravimetric results.

Highlights

Shale oil and gas are “unconventional” resources of natural oil and gas trapped in fine-grained sedimentary rocks called shale
The results clearly demonstrate that gum arabic (GA) has greatly reduced the corrosion rate (CR) of the metal in the tested environment, and the high corrosion inhibition activity of GA was influenced by both its concentration and CO2 partial pressure
Fe3 C were found with the X-ray photoelectron spectroscopy (XPS) analysis average depth of analysis for an measurement is approximately nm the cementite contrast to the results reported from the grazing incidence X-ray diffraction (GIXRD) analysis, where the characteristic peaks assigned to this formed on the surface at the early of 10)

Summary

Introduction

Shale oil and gas are “unconventional” resources of natural oil and gas trapped in fine-grained sedimentary rocks called shale. The rapid expansion of shale oil and gas exploration and the development of a new technology (i.e., hydraulic fracturing (HF) techniques), has seen the popularity of these natural resources to grow over the years. The injection of CO2 at high pressure into the wellbore is an effective method to increase the oil fields lifetime [1,2,3,4]. This process is usually referred to as carbon dioxide flooding enhanced oil recovery (CO2 -EOR). CO2 gas dissolves in the fluid to form the weak carbonic acid, which in turn

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