低含H2S工况下110SS的超临界CO2腐蚀行为

目的 明确低含H2S工况下,110SS钢在超临界CO2相中的适用性及腐蚀行为.方法 利用高温高压反应釜对高温高压低含H2S气井的井底腐蚀工况进行模拟,采用腐蚀失重法获取腐蚀速率,结合激光共聚焦显微镜、扫描电子显微镜(SEM)、能谱仪(EDS)及X射线衍射仪(XRD)对腐蚀行为进行分析研究.结果 在141℃、13.3 M...

Corrosion Behavior of 110SS Steel in Supercritical CO2 Phase under Environment with Low H2S

To clarify the applicability and corrosion mechanism of 110SS steel in supercritical CO2 phase under environment with low H2S,HTHP reactor was adopted to simulate the HTHP low H2S environment at the bottom of gas well.The corrosion rate was measured by weight loss methods;the corrosion behavior was analyzed by the laser scanning confocal microscope(LSCM),the scanning electron microscope(SEM),energy spectrum(EDS),and X-ray diffraction(XRD).The results show that 110 SS steel presents uniform corrosion characteristics in the supercritical CO2 phase containing saturated water,with corrosion rates of 0.017 mm/a at 141℃,13.3 MPa CO2 partial pressure,and 1.33 kPa H2S partial pressure.CO2 controls the corrosion.The corrosion film is distributed unevenly in the shape of water beads and has a monolayer structure.The corrosion products are mainly FeCO3,containing a small amount of H2S,and H2S corrosion is mostly concentrated in the interior of the water-bead area.The corrosion film is composed of discontinuous grains,and some parts of the matrix are directly exposed to the corrosive medium,so the protection of the matrix is limited.Taking 0.125 mm/a as the casing and tubing material selection standard,110 SS steel can be selected as casing and tubing material for gas wells with only condensate water and without water accumulation(T≤141℃,PCO2≤13.3 MPa,PH2S≤1.33 kPa,Cl^–≤4646 mg/L).