To elucidate the effects of Cl

-

and Ca

2+

on the corrosion and scale formation of 3Cr steel in CO

2

flooding-produced fluid

corrosion weight loss experiments

and titration experiments were conducted. The resulting products were characterized using scanning electron microscopy (SEM)

X-ray diffraction (XRD)

and X-ray photoelectron spectroscopy (XPS). This study examined the corrosion and scaling behavior of 3Cr steel under the influence of Cl

-

and Ca

2+

. The results indicate that both Cl

-

and Ca

2+

promote the corrosion of 3Cr steel. Notably

Cl

-

diminishes the promoting effect of Ca

2+

on corrosion and inhibits scaling

revealing a mutual enhancement between corrosion and scaling. The mechanisms of localized corrosion under varying concentrations of Cl

-

and Ca

2+

differ; under-scale corrosion occurs in environments with 5000 mg·L

-1

Cl

-

while Cl

-

induced corrosion is observed in 20000 mg·L

-1

Cl

-

environments. This study highlights that under the synergistic effects of Cl

-

Ca

2+

and scaling processes

the protective product film dissolves

thereby influencing both corrosion and scaling processes.