新型井下动态腐蚀试验装置的研制与应用

为了解江苏油田CO2腐蚀套管的机理及其影响因素，制定合理的套管防腐技术措施，自主研制了新型井下动态腐蚀试验装置，并利用该试验装置进行了井下动态腐蚀模拟试验。选择1/4圆弧N80钢挂片试样，模拟实际工况条件下流体对套管的腐蚀情况，对腐蚀速率及腐蚀形态进行测试评价，并对腐蚀产物的微观形貌进行了分析。试验结果显示，在试验研究的参数范围内，N80套管钢腐蚀速率较高，不同部位的平均腐蚀速率为0.168 9~0.571 8 mm/a，并随CO2分压、温度、流速增大而增大，表现出较严重的CO2局部腐蚀形态特征。微观形貌分析表明，流速是导致抽油泵吸入口附近套管腐蚀速率最大的主控因素，其腐蚀速率达到0.5718 mm/a，这与现场腐蚀套管穿孔情况相符。研究结果表明，该试验装置具有较好的模拟性和适用性，可为油套腐蚀机理试验研究提供新的测试手段。 

Development and Application of Downhole Dynamic Corrosion Test Device

In order to determine the influencing factors and mechanism of carbon dioxide corrosion in Jiangsu Oilfield and find a solution for casing corrosion,we independently developed dynamic corrosion experiment device,and carried out downhole dynamic corrosion experiments 1/4 arc steel sheet of Φ139.7 mm×Φ124.3 mm×16 was used to simulate carbon dioxide corrosion on casing at partial pressure of 0-2.5 MPa,temperature of 60-80 ℃,flow rate of 0.02-0.04 m/s,to evaluate the corrosion rate and corrosion morphology and analyze the micro-morphology of the corrosion products.Based on the experiment,casing corrosion mechanism was studied.Experimental results show that API N80 casing steel exhibits higher corrosion rate.The average corrosion rate is 0.168 9-0.571 8 mm/a,and would increases with the increase of the partial pressure of CO2,temperature and flow rate,resulting in serious carbon dioxide local corrosion morphology.The microstructure analysis shows that flow velocity is the main effect factor which causes corrosion of oil pump suction port near the casing,and its corrosion rate is 0.571 8 mm/a,which is consistent with the corrosion casing leakage situation on site.The research results show that the new experimental device can simulate the carbon dioxide corrosion accurately,providing a new test method for related experimental study on casing corrosion mechanism.