摘要：Nitrogen huff-n-puff (N-2 HnP) appears to be an economical and high-efficiency enhanced oil recovery (EOR) technique for tight oil reservoirs. There is however a lack of understanding of the pore-level EOR performance of N-2 HnP under tight reservoir conditions. In this work, a non-magnetic reactor was created and combined with a nuclear magnetic resonance (NMR) device for real-time monitoring of oil distribution in the HnP experiment. N-2 HnP experiments were then performed in a tight sandstone core sample at a temperature of 353 K and an injection pressure >= 24 MPa. The pore-level oil distribution under reservoir conditions was monitored and the EOR performance of N-2 HnP in specific pores was analyzed. The pore throat structures of the core sample and the phase behavior of the N-2-oil system were analyzed to elucidate the EOR mechanism of N-2 HnP. An oil recovery factor of 37.52% can be achieved after four cycles, which proves the EOR potential of N-2 HnP for tight reservoirs. The highest recoveries after N-2 HnP are obtained in the large pores, followed by the medium pores, the small pores, and finally the micro pores. Increases in soaking time and injection pressure resulted in slight and pronounced increases in oil recovery, respectively, both of which are mainly reflected in the first cycle. Specifically, increasing the soaking time only slightly improves the cumulative oil recovery in the small pores while increasing the injection pressure significantly improves the cumulative oil recovery in the small, medium, and large pores simultaneously. However, variations in both injection pressure and soaking time have a negligible effect on the cumulative oil recovery of the micro pores. (c) 2022 The Authors. Publishing services by Elsevier B.V. on behalf of KeAi Communications Co. Ltd.

关键字：Tight oil reservoirs; N-2 huff-n-puff; Pore-level production characteristics; Impact factors; Nuclear magnetic resonance

ISSN号：1672-5107

卷、期、页：卷: 19期: 6页: 2932-2940

发表日期：2022-12-01

影响因子：4.089900

期刊分区（SCI为中科院分区）：一区

收录情况：SCI（科学引文索引印刷版）,CSCD（中国科技引文期刊）（核心）,SCIE（科学引文索引网络版）

发表期刊名称：PETROLEUM SCIENCE

通讯作者：宋宜磊,张云飞,谢泽辉,张利超

第一作者：宋兆杰,王代刚,惠钢

论文类型：期刊论文

论文概要：宋宜磊,宋兆杰,张云飞,谢泽辉,张利超,王代刚,惠钢，Pore scale performance evaluation and impact factors in nitrogen huff-n-puff EOR for tight oil，PETROLEUM SCIENCE，2022，卷: 19期: 6页: 2932-2940

论文题目：Pore scale performance evaluation and impact factors in nitrogen huff-n-puff EOR for tight oil