Experimental Study of High-Temperature Resistant Gel System for Anti-Steam Channeling in Steam Flooding Heavy Oil Well

In order to improve the performance of sodium humate plugging agent at high temperature,high-temperature resistant gel system for steam channeling control was studied.Sodium humate was nitrified and associated with cross-linking agent with sufficient gel time and sufficient gel strength.Taking into account the impacts of mass fraction of sodium nitro-humate,formaldehyde and resorcinol,salts concentrations and pH value,the composition of high-temperature resistant gel system was optimized and its properties were evaluated through experiments.The optimum formula of the gel system was composed of 1.5%-2.5% formaldehyde,1.0%-2.0% resorcinol and 8.0%-10.0% sodium nitro-humate.The mass concentration of NaCl and CaCl2 of the gel system were 10 000 mg/L and 4 000 mg/L,respectively.It has the characteristics of salt resistance and high temperature tolerance as high as 290℃.The gel system has good plugging effects for the cores with various permeabilities and its plugging ratio is approximate to 95%.It is capable of selectively plugging highly permeable zones and functioning effectively for profile control and water shutoff,which demonstrates that the gel system completely meets the demands of anti-steam channeling in the process of steam injection.