聚驱后氮气泡沫调驱技术

NITROGEN FOAM PROFILE-CONTROLLING AND FLOODING TECHNIQUE AFTER THE POLYMER FLOODING

聚驱后油层内仍有40%~50%的剩余油未被采出。为了进一步提高原油采收率,开展了聚驱后氮气泡沫调驱技术研究。采用动静实验技术,优选出了适合大庆油田的发泡剂3#A及其最佳发泡质量分数;系统研究了氮气泡沫阻力系数和驱替效果;在室内综合研究基础上,进行了现场应用试验。研究结果表明:发泡剂3#A的质量分数大于0.3%时,氮气泡沫性能最佳;既能有效封堵大孔径孔隙,又能提高小孔径内剩余油采收率,最终采收率可达到79%,较聚驱提高近5百分点。现场试验表明,聚驱后氮气泡沫调驱技术具有改善油层动用状况,减缓层间矛盾,降低综合含水率等优势。研究成果为聚驱后进一步提高采收率提供了重要理论和实践依据。

There still exits 40% ~ 50% remained oil that has not been produced after the polymer flooding,so in order to further enhance the oil recovery,the researches on the Nitrogen foam profile-controlling and flooding technique after the polymer flooding were conducted. With the help of the dynamic and static test technologies,Foam Agent 3#A and its optimal foaming mass fraction were chosen for Daqing Oilfield; the resistance coefficients and displacement effects of the nitrogen foam were systematically studied; and furthermore on the basis of the laboratory comprehensive study,the field application test was carried out. The achievements show that the foam performances are the best when the mass fraction of Foam Agent 3 #A is above 0. 3% : not only can effectively plug the large pores,but also improve the recovery of the remained oil in the small pores,the ultimate recovery can reach to79%,compared with the polymer flooding,the EOR is nearly 5%. The field test shows that this technology can improve the developed conditions of the oil layers,release the interbedded contradiction,reduce the combined wa-ter cut and so on. In a word,the study achievements have provided the important theories and practical evidences for the further EOR after the polymer flooding.