高性能深部调驱体系试验

 应用交联聚合物体系对油层进行深部调驱可有效提高原油采收率。在70℃条件下,通过正交试验优选出了一种交联聚合物调驱体系,其主剂基本组成为0.30%聚合物+0.08%有机铬+0.10%六亚甲基四胺+0.08%苯酚。为延长该体系的成胶时间,考查了延迟交联剂草酸钠(SO)对体系成胶时间和强度的影响。选定SO的质量分数为0.04%时,体系的成胶时间约为48h,成胶强度约为0.057MPa。矿化度、温度、pH值等因素可对体系的成胶性能产生影响。在70℃条件下,当Na+质量浓度小于36000mg/L,Cacl2质量浓度小于1000mg/L,pH值为5—7时,体系具有较好的成胶性能；体系在60—90℃条件下生成的冻胶强度大于0.056MPa。使用单管岩心驱替试验模拟了体系的调驱性能,结果表明,体系的调驱效果较好,水驱后采收率提高幅度高达20%以上,封堵率大于95%,加之70℃下成胶时间在48h以上,可以达到油层深部调驱的目的。

Laboratory Experiment on the High Performance System for Deep Profile Control and Flooding

The recovery efficiency of oil could be enhanced by using compound cross-linking polyacrylamide system of deep profile control and flooding. The formula contained main agents of a cross-linking polyacrylamide system which consisted of 0.30% HPAM, 0.08% organic chromium, and 0.10% hexamethylenetetramine is optimized by orthogonal test under the 70℃ condition. In order to prolong the gel time of system, the effects of delayed cross-linker SO on gel time and gel strength are researched. Gel time of system is 48h and gel strength is 0.057MPa when the concentration of SO is 0.04%. The performance of system could be affected by salinity, temperature, pH value, and other factors. When the concentration of Na⁺ is under 36,000 mg/L, the concentration of Ca²⁺ is below 1,000mg/L, the gel strength of system could be higher than 0.040MPa. When pH is between five and seven, the gel strength of system could be above 0.065MPa; however, the gel time is shorter. When temperature is between 60℃ and 90℃, the gel strength of system is about 0.056MPa and changes slightly, however when temperature is between 50℃ and 60℃, the gel strength of system changes greatly. The deep profile control and flooding performance of system is researched by using single tube core displacement experiment. The results show that the oil recovery could be enhanced about 20% after water flooding and the plugging rate is higher than 90% by using that system. Because the gel time of system is above 48h, therefore the performances of that cross-linking polyacrylamide system could satisfy the requirements for deep profile control and flooding in oil layers.