无固化剂水性树脂提高固井水泥石抗腐蚀性能

Corrosion Resistance Improvement of Cement Paste by Waterborne Resin without Curing Agent

邓成辉 金勇

DENG Chenghui JIN Yong

含CO2油气井、CO2地质封存井等特殊工况对水泥石的抗腐蚀能力要求高。为提高固井水泥石的抗腐蚀能 力，选择了一种无固化剂水性树脂作为防腐材料，分析了水性树脂提高水泥石的防腐能力和作用机理。结果表 明，树脂可有效提高水泥石的抗腐蚀能力。腐蚀28 d 后，水性树脂掺量15%的水泥石腐蚀深度比空白水泥石下 降了68.7%，腐蚀后的抗压强度比未腐蚀的下降了12.8%。树脂掺入水泥浆不仅降低了水泥石的渗透率，而且降 低了水泥石的大孔径体积，增大了CO2水溶液腐蚀的流动阻力。树脂掺入水泥浆后减少了水泥石腐蚀产物的形 成。掺入树脂的水泥石微观结构致密程度更高，内部存在的膜状物质提高了腐蚀反应的惰性。无固化剂水性树脂 通过降低碱性水化产物形成、提高酸性流体渗入阻力以及增强腐蚀反应惰性多种方式提高水泥石的抗腐蚀能力。

Special geological conditions such as oil and gas wells with CO2 and CO2 geological storage wells require high corrosion resistance of cement paste. In order to improve the corrosion resistance of cement paste，a waterborne resin without curing agent was selected as the anti-corrosion material. The improvement mechanism of corrosion resistance of cement paste by waterborne resin was analyzed. The results showed that the resin could effectively improve the corrosion resistance of cement paste. After 28 days of corrosion，the corrosion depth of cement paste with 15% waterborne resin was 68.7% lower than that of blank cement paste，meanwhile the compressive strength after corrosion was 12.8% lower than that without corrosion. The mixture of resin and cement slurry not only reduced the permeability of cement paste，but also reduced the large pore volume，therefore increased the corrosion flow resistance of CO2 aqueous solution. The corrosion product formation of cement paste was reduced after resin was added into cement slurry. The microstructure of cement paste mixed with resin was denser. The film substance in cement paste increased the inertia of corrosion reaction. The waterborne resin without curing agent could improve the corrosion resistance of cement paste by reducing the formation of alkaline hydration product，increasing the penetration resistance to acid fluid and enhancing the inertia of corrosion reaction.

10.19346/j.cnki.1000-4092.2022.04.003