神木气田中深层酸性气藏采出井含CO₂/H₂S，采出液中Cl^-浓度高达30 000 mg/L，井筒温度最高可达100 ℃，井下管柱面临着严峻的腐蚀风险。为此采用高温高压釜模拟井筒内管柱服役工况，研究了不同温度（20~100 ℃）、CO₂分压（0.5~2 MPa）、H₂S分压（0~0.7 MPa）下N80钢的腐蚀规律，分析了腐蚀产物膜的微观形貌和组成成分，明确了油管腐蚀主控因素，并基于腐蚀速率对管柱安全服役寿命进行评估。结果表明：N80钢腐蚀程度属于极严重腐蚀，影响油套管腐蚀的主控因素是温度，当服役温度为80 ℃时，N80的安全服役寿命最短为7.3年；在CO₂-H₂S-Cl^-共存环境下，CO₂和H₂S之间存在竞争和协同作用，少量H₂S会优先生成更为致密的FeS从而抑制FeCO₃的生成，高浓度H₂S会促进CO₂腐蚀，同时Cl^-对腐蚀产物膜造成破坏，并在点蚀坑内富集。研究结果为CO₂-H₂S-Cl^-环境中管柱的安全服役寿命评估和腐蚀防护方案的制定提供数据参考和理论依据。

The medium-to-deep acidic gas wells in Shenmu Gas Field produce fluids containing CO₂/H₂S, with chloride (Cl^-) concentrations in the produced liquid reaching as high as 30 000 mg/L and wellbore temperatures up to 100 ℃. These conditions pose severe corrosion risks to the downhole tubing strings. To address this, a high-temperature and high-pressure autoclave was used to simulate the operating conditions of the tubing strings within the wellbore. The corrosion behavior of N80 steel was studied under different temperatures (20 ~ 100 ℃), CO₂ partial pressures (0.5 ~ 2 MPa), and H₂S partial pressures (0 ~ 0.7 MPa). The micromorphology and composition of the corrosion product films were analyzed to identify the main controlling factors for tubing corrosion. Additionally, the safe service life of the tubing was assessed based on the corrosion rate. The results indicate that the corrosion of N80 steel is extremely severe, and temperature is the primary controlling factor affecting the corrosion of tubing and casing. When the operating temperature is 80 ℃, the minimum safe service life of N80 steel is 7.3 years. In the coexistence environment of CO₂-H₂S-Cl^-, there are competitive and synergistic effects between CO₂ and H₂S. A small amount of H₂S preferentially forms a denser FeS, which inhibits the formation of FeCO₃. However, high concentrations of H₂S accelerate CO₂ corrosion. Meanwhile, Cl^- damages the corrosion product films and accumulates in pitting corrosion pits. The findings provide data references and theoretical support for assessing the safe service life of tubing strings and formulating corrosion protection strategies in CO₂-H₂S-Cl ^- environments.