期刊名称：IOP Conference Series: Earth and Environmental Science
印刷版ISSN：1755-1307
电子版ISSN：1755-1315
出版年度：2019
卷号：252
期号：5
页码：1-12
DOI：10.1088/1755-1315/252/5/052088
出版社：IOP Publishing
摘要：Tight oil is considered as the most expecting alternative resource after the conventional fossil energy exploration. In this work, the oil recovery efficiencies of nitrogen huff-n-puff process in ten cylinder cores and in a three dimensional model from Yanchang tight oil reservoir were investigated. The results indicated that the pressure propagation in nitrogen huff–n-puff process was much deeper and faster, which contributed to the higher oil recovery, compared to water huff–n-puff. The pressure depletion rate was the dominating factor for enhancing oil recovery, meanwhile, the injection velocity and the closed time had little effect on oil recoveries. Moreover, the evidence from numerical simulation showed that natural energy exhaustion was remarkably supplemented at the first circle of nitrogen injection; and around 25% of the oil saturation was recovered by nitrogen huff-n-puff. Our study implied that nitrogen huff–n-puff process might have robust application for enhancing oil recovery in Yanchang tight oil formation.
