PSI - Issue 68

M. Hadj Meliani et al. / Procedia Structural Integrity 68 (2025) 292–296 M. H. Meliani et al. / Structural Integrity Procedia 00 (2025) 000–000

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2.1.3. Oilfield Water The oilfield water sample was obtained from an oil field located in Hassi Messaoud, in the southern region of Algeria. 2.2. Weight loss Weight loss assessments were performed to quantitatively evaluate the corrosion rates of carbon steel samples in oilfield water, both in the presence and absence of the green inhibitor. The steel coupons were first weighed, then immersed in each test solution within a thermostatically controlled water bath. After exposure, the coupons were cleaned with Clarke’s solution following the ASTM G1-03 standard to eliminate any corrosion products, and then reweighed to determine the weight loss. V !"## = &× ∆ ( % ×) ×100 (1) where: V corr : corrosion rate, ∆W=W * −W + , W: weight loss, t: exposure time of the steel coupon, ρ: density of carbon steel (7.8 g/cm 3 ), S: surface area of the coupon. 2.3. Electrochemical measurements The electrochemical setup consisted of a potentiostat/galvanostat and a frequency analyzer. In this study, X52 steel served as the working electrode, a saturated calomel electrode (SCE) was used as the reference electrode, and a platinum plate acted as the counter electrode. Prior to the electrochemical tests, the electrodes were polished using 1200-grit abrasive paper and rinsed with double distilled water. The electrochemical experiments commenced after immersing the electrodes in oilfield water for 30 minutes. Measurements were conducted using open circuit potential (OCP), linear polarization resistance (LPR), and electrochemical impedance spectroscopy (EIS) techniques. 2.4. Surface analysis For the surface analyses, one face of the X52 steel was prepared using metallographic techniques. Initially, each alloy was ground progressively with emery paper ranging from coarse (120 grit) to fine (1200 grit). Following this, the surfaces were washed with bidistilled water to remove any residual particles. The cleaned specimens were then placed in glass bottles, where they were immersed in an oilfield water, both with and without the presence of the green inhibitor and allowed to sit for a week. After this period, the specimens were carefully removed from the solution, and their surfaces were examined using scanning electron microscopy (SEM) coupled with energy-dispersive X-ray spectroscopy (EDX) for detailed analysis [6]. 3. Results and discussion 3.1. Weight loss Table 1 presents corrosion rate and inhibition efficiency evaluated by weight loss method in presence and absence of Calotropis procera. Significant corrosion inhibition even at low concentrations, 5ppm CP reduces weight loss and corrosion rate by over 50% ,10ppm CP shows best overall results

Table 1. Corrosion rate and inhibition efficiency evaluated by weight loss method in presence and absence of plant extract. Inhibitor concentration (ppm) Corrosion rate (mm/year) Inhibition Efficiency (%) 0 0.095 - 5 0.045 52.63 7 0.031 67.36 10 0.013 86.31