无机凝胶成胶性能及封堵效果实验

Experimental study on gelling property and plugging effect of inorganic gel system(OMGL)

利用仪器检测和理论分析方法，研究了无机凝胶转向剂（OMGL）的凝胶化程度、极限成胶浓度和封堵性能，并观测了岩石孔隙骨架表面无机凝胶形貌。结果表明：OMGL溶液与水中Ca抖反应可生成无机凝胶。OMGL和ca2＋浓度愈大，凝胶化程度愈大，OMGL浓度是ca2＋浓度的2～3倍时，无机凝胶化程度最为合理。凝胶化程度对温度不敏感。在岩心渗透率相同条件下，随OMGL浓度增加，残余阻力系数增大；在OMGL浓度相同条件下，随岩心渗透率增加，残余阻力系数减小。OMGL溶液和ca2＋溶液浓度组合与岩心渗透率间存在合理匹配关系，可根据ca2＋浓度推测岩心的封堵效果。无机凝胶以“-si-0-si-”离子键方式在岩石骨架表面吸附形成涂层，而非沉淀在通道中。

By means of instrumental test and theoretical analysis, the gelling degree, extreme gelation concentration and plugging performance of inorganic gel （OMGL） were studied and its appearance on surface of rock skeleton was observed. Results show that inorganic gel is formed by reaction between OMGL system and Ca2＋. The higher the concentration of OMGL and Ca2＋, the higher the gelling degree. When the concentration of OMGL system is 2 to 3 times that of Ca〉, the inorganic gelling degree is the most suitable. The gelling degree is not sensitive to temperature. Under the same core permeability, residual resistance factor increases with the increase of concentration of OMGL system. When the concentration of OMGL system remains constant, residual resistance factor decreases with the increase of core permeability. There exists a reasonable matching relation between core permeability and concentration ratio of OMGL system and Ca2＋. Plugging effect of cores can be speculated from Ca2＋concentration. The inorganic gel coats on rock surface by absorption in the form of ionic bond of＂-Si-O-Si-＂ instead of depositing in the channels.