油气藏评价与开发 ›› 2024, Vol. 14 ›› Issue (1): 42-47.doi: 10.13809/j.cnki.cn32-1825/te.2024.01.006

• 方法理论 • 上一篇    下一篇

页岩油藏注CO2驱孔隙动用特征研究

张志超(),柏明星,杜思宇   

  1. 东北石油大学提高采收率教育部重点实验室,黑龙江 大庆 163318
  • 收稿日期:2023-01-09 出版日期:2024-02-26 发布日期:2024-03-05
  • 作者简介:张志超(1987—),男,博士研究生,工程师,主要从事CO2地质埋存及驱油相关研究。地址:黑龙江省大庆市龙凤区发展路199号,邮政编码:163318。E-mail:zhangzhichao@nepu.edu.cn
  • 基金资助:
    国家自然科学基金“枯竭油藏型储气库二氧化碳作垫层气机理及注采动态规律研究”(52174020)

Characteristics of pore dynamics in shale reservoirs by CO2 flooding

ZHANG Zhichao(),BAI Mingxing,DU Siyu   

  1. Key Laboratory of EOR, Ministry of Education, Northeast Petroleum University, Daqing, Heilongjiang 163318, China
  • Received:2023-01-09 Online:2024-02-26 Published:2024-03-05

摘要:

CO2在页岩油藏驱油时的孔隙动用特征是评价其应用于提高页岩油藏采收率效果的一项重要指标。因此,开展了超临界CO2驱替页岩岩心室内实验,并以核磁共振(NMR)在线岩心扫描技术为手段对CO2驱页岩油藏的孔隙动用特征和规律进行研究。结果表明,超临界CO2非混相驱油主要动用页岩中孔隙半径在0.1~3.0 μm范围内的油,而此过程中小于0.008 μm孔隙半径内的油量反而增加,分析原因主要是CO2在页岩层中通过压差和扩散作用将大孔隙内页岩油带入小孔隙中并发生吸附滞留,在驱替时间5 h后,CO2驱替页岩油采收率达到35.7%,驱油效果较好。

关键词: 超临界CO2, 页岩油, 核磁共振, 孔隙动用特征, 采收率

Abstract:

The pore utilization characteristics of CO2 during shale oil displacement are a crucial indicator for evaluating its effectiveness in enhancing shale oil reservoir recovery rates. Therefore, experiments on supercritical CO2 displacing shale cores were conducted in the laboratory, and nuclear magnetic resonance(NMR) online core scanning technology was used to study the pore utilization characteristics and patterns of CO2 displacement in shale oil reservoirs. The results indicate that immiscible flooding by supercritical CO2 mainly develops the oil in shale pores with radius of 0.1~3.0 μm, but the oil content in pore radius less than 0.008 μm actually increases. The analysis shows that CO2 brings shale oil from large pores into small pores through pressure difference and diffusion effect in the shale layer and makes oil undergo adsorption and retention. After a displacement time of five hours, the recovery rate of shale oil by CO2 displacement reached 35.7%, indicating a relatively effective oil displacement result.

Key words: supercritical CO2, shale oil, nuclear magnetic resonance, pore development characteristic, oil recovery

中图分类号: 

  • TE357