Study on the Law and Influencing Factors of Spontaneous Imbibition in Chang 7 Reservoir of Ordos Basin

Abstract This paper examines the imbibition and oil displacement process of fracturing fluid in a laboratory setting, focusing on the Chang 7 tight oil reservoir block in Ordos Basin. The study investigates the capability of different imbibition fluid systems to alter wettability and reduce interfacial tension. Additionally, it explores the imbibition and oil displacement abilities of cores with varying levels of wettability and permeability focusing on the imbibition equilibrium time, imbibition recovery rate, and the imbibition recovery multiplier. The reasons for these results were also examined. A multivariate nonlinear regression model is established to analyze the relationship between imbibition recovery, capillary radius, wettability angle, and interfacial tension. Additionally, neural network analysis is employed to determine the significance of these influencing factors. The findings from this research provide theoretical guidance for enhancing understanding of imbibition mechanisms and improving recovery rates in tight oil reservoirs.