海上油田聚驱后聚表二元驱实验研究及应用

Experiment research and application of polymer-surfactant flooding after polymer flooding in offshore oilfield

聚合物驱是提高海上油田采收率的重要手段,但注聚末期增油效果逐渐变差,且剩余油更加难以动用。为了进一步扩大化学驱效果,针对渤海J油田开展了聚表二元驱驱油实验,实验结果表明,聚表二元驱较聚驱采收率有明显的增加;适当增加二元驱段塞,采收率增值变大;随转二元驱时机含水率的升高,增油幅度变小,考虑经济性,宜在中高含水期进行聚表二元驱。矿场试验表明聚表二元驱能够在聚驱后改善开发效果,平均单井增油幅度达到25%左右。

Polymer flooding is an important way to enhance oil recovery in offshore oilfields,but the increasing oil production gradually becomes poor at the end of polymer flooding,and it is difficult to recovery remaining oil.To further enlarge the effect of chemical flooding,it was carried out experiments of polymer-surfactant flooding for J Oilfield in Bohai.The experimental results showed that the oil recovery rate of polymer-surfactant flooding is obviously higher than that of polymer flooding.The bigger the slug size of polymer-surfactant flooding is,the higher the oil recovery rate is.The later the timing of polymer-surfactant flooding namely the higher water cut is,the lower the oil recovery rate is.Therefore,based on the economical efficiency of project,it is suitable to implement the polymer-surfactant flooding at the medium-high water cut stage.The field results indicated that the polymer-surfactant flooding can increase the development effect after polymer flooding,with an average increased oil rate of about 25%for single well.