Petroleum Reservoir Evaluation and Development ›› 2025, Vol. 15 ›› Issue (1): 73-78.doi: 10.13809/j.cnki.cn32-1825/te.2025.01.009

• Oil and Gas Development • Previous Articles     Next Articles

Study on the influence of shale oil saturation on imbibition recovery rate

ZHOU Xu1(), MA Chao1,2,3(), LIU Chao1, TANG Jiajing1, LIU Yilin1   

  1. 1. School of Petroleum Engineering, Yangtze University, Wuhan, Hubei 430100, China
    2. Key Laboratory of Drilling and Production Engineering for Oil and Gas of Hubei Province, Yangtze University, Wuhan, Hubei 430100, China
    3. National Engineering Research Center for Oil and Gas Drilling and Completion Technology, School of Petroleum Engineering, Yangtze University, Wuhan, Hubei 430100, China
  • Received:2024-07-19 Online:2025-01-26 Published:2025-02-26
  • Contact: MA Chao E-mail:2022710342@yangtzeu.edu.cn;500526@yangtzeu.edu.cn

Abstract:

To investigate the influence of shale oil with different oil saturation on imbibition recovery rate, shale samples from the Jiangling sag in the Jianghan Basin were taken as the research object. Imbibition experiments were conducted to examine the variation of core imbibition curves at oil saturation of 20%, 30%, 40%, and 50% under conditions of similar and increasing permeability. Nuclear magnetic resonance (NMR) technology was used to analyze the changes in oil-phase signals within the core pores before and after imbibition. Additionally, the imbibition volume and oil displacement volume during the imbibition process were compared. The results showed that under similar permeability conditions, cores with higher oil saturation exhibited higher imbibition recovery rates. In contrast, cores with higher oil saturation had slower imbibition rates at the initial stage of imbibition and required a longer time to reach imbibition equilibrium. When permeability gradually increased, cores with higher oil saturation achieved higher imbibition recovery rates. In this case, cores with higher oil saturation also exhibited faster imbibition rates in the early stages compared to those with lower oil saturation. The hydration and expansion of shale resulted in the imbibition volume exceeding the oil displacement volume during the imbibition process. Moreover, the difference between these two volumes increased with higher oil saturation. The findings of this study provide a theoretical basis for improving shale oil recovery.

Key words: shale oil, oil saturation, imbibition recovery rate, imbibition rate, nuclear magnetic resonance

CLC Number: 

  • TE122