蒸汽驱稠油井防汽窜高温凝胶调堵体系试验研究

为了提高腐殖酸钠调堵剂在注蒸汽高温条件下的性能,对控制汽窜高温凝胶调堵体系进行了研究。将腐殖酸钠进行硝化处理,并辅以交联剂,以具有较长的成胶时间和较高的成胶强度为标准,考察了硝基腐殖酸钠、甲醛和间苯二酚的质量分数,盐质量浓度及pH值对凝胶调堵体系性能的影响,从而配制出具有耐高温性能的硝基腐植酸钠凝胶调堵体系,并通过试验对其性能进行评价。控制汽窜高温凝胶调堵体系的最佳配方为1.5%~2.5%甲醛+1.0%~2.0%间苯二酚+8.0%~10.0%硝基腐殖酸钠。该调堵体系具有很好的抗盐特性及耐温性能,质量浓度10 000 mg/L NaCl和质量浓度4 000 mg/L CaCl2对其性能影响不大,最高可耐290℃的高温。该调堵体系对不同渗透率的岩心都具有良好的封堵效果,封堵率在95%左右,能选择封堵高渗透层,起到调剖堵水的作用。这表明该凝胶调堵体系能封堵高渗透层,起到调剖的作用,能满足蒸汽驱稠油井防汽窜的要求。 

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.