Nano-pores dominate the storage space of tight reservoirs and the connectivity of pore throat system is complex. The diameter of organic matter pores and intra-particle pores in marine shale with high maturity of southern China are 20~890 nm. The pores in terrestrial shale are organic matter pores and matrix pores, with diameter between 30~200 nm. The storage space in tight sandstone includes dissolution pores and micro-fractures with diameter in 10~200 μm. Nano-pores are composed by inter-particle pores and inter-crystal pores with diameter 70~400 nm. The calcite dissolution pores, inter-particle dissolution pores and micro-fractures dominate the nano-pores in tight limestones and the diameter is 50~500 nm. Reservoir digenetic modeling data indicates that total porosity in shale increases firstly and decreased later with the increase of|temperature and pressure. Four occurrences of oil in nano-pores have been distinguished and inter-particle pores are the most favorable for the oil accumulation. Moreover, due to the special characteristics of unconventional oil and gas, further work should be focused on the instrument improvement, technology innovation and evaluation parameter optimization.
Zhu Rukai,Bai Bin,Cui Jingwei et al. Research advances of microstructure in unconventional tight oil and gas reservoirs[J]. JOPC, 2013, 15(5): 615-623.
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