X80管线钢在不同矿化度油田采出液中的腐蚀行为研究

Corrosion Behavior of X80 Pipeline Steel in the Different-salinity Oilfield Fluids

为了研究X80管线钢在不同矿化度油田采出液中的腐蚀行为,利用高温高压釜动态模拟试验研究了在60℃、 CO_2分压1.5 MPa、流速1.5 m/s、含水率40%条件下不同矿化度对X80管线钢在模拟油田采出液中的腐蚀情况,并利用扫描电镜(SEM)、能谱仪(EDS)和X射线衍射仪(XRD)对试样表面腐蚀产物形貌和成分进行了分析。结果表明,随矿化度增加, X80钢平均腐蚀速率降低,腐蚀形态呈现严重局部点蚀、轻微点蚀和均匀腐蚀的变化规律;腐蚀产物膜厚度随矿化度降低而减小,在矿化度为20 g/L时,试验钢的腐蚀最为严重,产物膜最厚,腐蚀产物主要为FeCO_3及少量Fe和CaCO_3。

In order to make X80 pipeline steel use as crude oil gathering pipeline, the dynamic simulation test of high temperature autoclave was used to study the corrosion of X80 pipeline steel in simulated oilfield production fluid with different salinity under the conditions of temperature 60 ℃, CO2 partial pressure 1.5 MPa, flow rate 1.5 m/s and water content 40%. The morphology and composition of the corrosion products on the surface of the samples were analyzed by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and X-ray diffractometry (XRD). The results show that the average corrosion rate of X80 steel decreased with the increasing salinity, and the corrosion morphology showed severe local pitting, slight pitting and uniform corrosion with the change of salinity. The corrosion product film thickness decreases with the decrease of salinity. At 20 g/L, the corrosion of the test steel was the most serious, and the product film is the thickest. The corrosion products are mainly FeCO3, a small amount of Fe and CaCO3.