Study on permeability characteristics of tight oil reservoir through high-pressure mercury injection

In the 21st century, the focus of global oil and gas development has shifted from conventional reservoirs to unconventional reservoirs. As one of the unconventional oil and gas resources, tight oil has a good development prospect. Xu et al. (2019a) established gas apparent permeability model based on flow regime in tight sandstone reservoirs by combination of molecular kinetics, gas transport mechanisms, and apparent permeability. Their study provides a quick evaluation of gas apparent permeability based on Knudsen number and pore diameter which is greatly helpful for reservoir evaluation. By analyzing the sedimentary environment and reservoir-forming conditions of the Carboniferous-Permian in North China, Kang pointed out that the Carboniferous-Permian in North China is one of the important strata for improving oil and gas reserves and production in China’s current and future tight oil and gas fields (Kang, 2020). Through molecular simulation and physical experiment, Xu et al. (2017) investigated the free gas transport in shale rocks by using the equation of state (EOS) and elastic hard-sphere (HS) model. Excellent results were obtained concerning the mechanism underlying the transport of gas in shale rock nanopores. Liao et al. (2011) discussed the petroleum exploration prospects of the tight reservoirs in the Sichuan Basin from the perspective of correlation with the Bakken Formation in the Williston Basin of the United States. The study shows that the Jurassic in central Sichuan is a typical continuous oil accumulation, and puts forward an effective way to open up a new situation of oil exploration and development in the Jurassic tight reservoirs in central Sichuan. Wang et al. (2019) considered that Dujiatai oil reservoir in the fourth member of Shahejie Formation in Leijia area is a favorable exploration area for tight-shale oil through comprehensive analysis of source-reservoir combination based on the analysis results of cast thin section and scanning electron microscope, and put forward the overall development strategy for tight-shale oil. Xu et al. (2019b) raised an better approach to study gas transport in shale rocks by combining nanoscale pore size distribution (PSD) and gas filed production. Findings of this study are validated by field test and are helpful to better understand the relation between a nanoscale PSD and field gas production.