Rapid Corrosion Evaluation Technology in Carbon Dioxide Flooding Wells Via Metal Ions Analysis

Abstract

Abstract. During carbon dioxide (CO2) flooding operations, tubular corrosion poses significant threats to production safety and CO2 storage efficiency. This study investigated oil wells within the H38 CO2 injection area (experimental group) and non-injection wells (control group) of Yanchang Oilfield. Concentrations of indicator metal elements in produced fluids were analyzed using an inductively coupled plasma mass spectrometer. Integrated statistical methods and field validation revealed significantly higher Fe concentrations in the experimental group (2.80 × 102–5.15 × 105 μg/l) compared to the control group (3.22 × 102–6.78 × 103 μg/l). While Ni showed a strong positive correlation with Fe concentration (r = 0.999, p < 0.01). HCO3− intensified corrosion through a dual “acidification-complexation” mechanism, with its concentration increasing by 1.8–5.5 times, in gas-breakthrough wells and showing significant correlations with Fe (r = 0.78, p < 0.01) and Ni (r = 0.76, p < 0.05). This establishes a self-sustaining “corrosion-dissolution-precipitation” cycle. A three-tier corrosion grading system (A/B/C) was developed using the percentile method (P25/P75), validated by field corrosion rates (Grade C: >0.2 mm/a). Compared to traditional coupon methods, this metal element analysis-based approach offers lower cost and shorter detection cycles. This study provides an efficient and low-cost solution for real-time tubular corrosion monitoring in carbon dioxide-enhanced oil recovery projects.