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Cores from shale reservoirs in Subei Oilfield were taken as sample to study the effects of surfactants on the oil displacement efficiency and the main controlling factors of imbibition in shale reservoirs. The TOC analysis and scanning microscope technique （SEM） were used to characterize the pore structure of the core samples. Imbibition experiments under the influence of multiple factors were conducted using nuclear magnetic resonance （NMR） technology. Then the effects of factors were evaluated such as wettability， fractures， porosities， permeability， surfactant concentrations， and types on the imbibition efficiency of shale oil reservoirs， and the distribution characteristics and producing conditions of the oil in different pores were clarified during the imbibition process. The results showed that shale imbibition could be divided into three stages： early stage， middle stage， and late stage. The imbibition rate was high in the early stage， and the imbibition efficiency increased rapidly. The middle stage accounted for the longest period， and the imbibition rate slowed down in the late stage， with the imbibition efficiency tending to be stable. By comparing the effects of different factors on imbibition， it was found that a wetter core indicated more fractures and higher imbibition rate and efficiency. Moreover， a higher porosity and lower permeability led to higher imbibition efficiency. The imbibition efficiency showed an increasing trend with the concentration of surfactants decreasing. The NMR experimental results demonstrated that in the process of shale imbibition， the produced oil of micro-pores was more than that of macro-pores， and changing the imbibition conditions could improve the producing percentage of oil in various pores.

in order to better promote the transportation industry to reduce carbon emissions and improve the competitiveness of railway freight in the whole freight market, to achieve the “double carbon” strategy and promote the “transit rail”. In this paper, considering the dynamic pricing of freight volume and freight price, a two-layer programming model is established under the minimum social total cost of railway and road. The upper level considers the income of railway freight, and the lower level considers the total social cost of freight transportation, so as to realize the increase of railway freight revenue and the decrease of the general total expenditure paid by freight owners. Considering the transportation of bulk commodity freight from shandong to sichuan, it is concluded that the railway freight market has a good development prospect under the consideration of the total social expenditure such as carbon emission. Under the carbon emission charge, the appropriate increase of railway freight rate will not lead to the reduction of railway freight volume. As rail freight becomes more competitive under increasingly stringent carbon emissions penalties, the volume of rail freight will continue to rise even after appropriate increases in rail freight fees. At this point, rail freight companies can transport more goods and gain higher returns, slightly increasing the overall cost borne by shippers in a broad sense, and helping to reduce carbon emissions in the process of freight transport.