Song Jianjian, Xu Mingbiao, Tan Chunqin, You Fuchang, Wang Xiaoliang, Zhou Shanshan
Cooperative Innovation Center of Unconventional Oil and Gas, Ministry of Education & Hubei Province, Yangtze University, Wuhan 430100, China.
School of Petroleum Engineering, Yangtze University, Wuhan 430100, China.
Materials (Basel). 2022 Jul 29;15(15):5258. doi: 10.3390/ma15155258.
Oil-well cement-based materials have inherent brittleness; therefore, they cannot be directly used to seal oil and gas wells for a long time. To improve the elasticity of oil-well cement-based composites, a flexible epoxy resin system was developed. The flexibility, TG, and SEM of the cured resin system were evaluated. At the same time, the resin was added to oil-well cement-based materials to improve its elasticity. The compressive strength and elastic modulus of resin cement stone were tested, and the microstructure was analyzed by XRD, TG, and SEM/EDS. The results showed that the structure of the cured resin is compact, the thermal decomposition temperature is 243.9 °C, and it can recover its original shape after compression. At the curing age of 28 days, the compressive strength of cement-based composites containing 30% resin decreased by 26.7%, while the elastic modulus significantly decreased by 63.2%, and the elasticity of cement-based composites was significantly improved. The formation of hydration products (e.g., calcium silicate hydrate, and calcium hydroxide) in the resin cement slurry is obviously lower than that of pure cement, which is the reason for the decrease in compressive strength. The flexible structure of polymer particles and polymer film formed by epoxy resin is distributed inside the cement stone, which significantly improves the elasticity of oil-well cement-based composites. The results of this paper are helpful for the design of elastic cement slurry systems.
油井水泥基材料具有固有的脆性，因此，它们不能直接长期用于密封油气井。为了提高油井水泥基复合材料的弹性，开发了一种柔性环氧树脂体系。对固化树脂体系的柔韧性、热重分析（TG）和扫描电子显微镜（SEM）进行了评估。同时，将该树脂添加到油井水泥基材料中以提高其弹性。测试了树脂水泥石的抗压强度和弹性模量，并通过X射线衍射（XRD）、热重分析（TG）和扫描电子显微镜/能谱仪（SEM/EDS）对微观结构进行了分析。结果表明，固化树脂结构致密，热分解温度为243.9℃，压缩后能恢复原状。在28天的养护龄期，含30%树脂的水泥基复合材料的抗压强度降低了26.7%，而弹性模量显著降低了63.2%，水泥基复合材料的弹性得到显著提高。树脂水泥浆体中水化产物（如硅酸钙水化物和氢氧化钙）的生成明显低于纯水泥，这是抗压强度降低的原因。环氧树脂形成的聚合物颗粒和聚合物膜的柔性结构分布在水泥石内部，显著提高了油井水泥基复合材料的弹性。本文的研究结果有助于弹性水泥浆体系的设计。
