关键词: 长4+5油层组：油气成藏条件, 油气成藏机制, 林镇地区：鄂尔多斯盆地

Abstract:

In order to investigate the pore characteristics and methane adsorption capacity of Chang 7 shale of Yanchang Formation in the southeastern Ordos Basin, eight core samples were selected to carry out experiments, such as Arion milling field emission scanning electron microscope, low-temperature nitrogen adsorption and isothermal adsorption. The results show that five types of microcosmic pores are mainly developed,including intergranular pores, intragranular pores, intergranular pores in pyrite, organic pores and microfractures. The specific surface area ranges from 1.166 m2/g to 6.964 m2/g by BET equation, pore volume ranges from 0.004 8 m3/g to 0.024 2 m3/g by BJH equation, and the average pore diameter ranges from 8.812 nm to 17.882 nm. The methane adsorption capacity of Chang 7 shale under actual reservoir condition was simulated, and the maximum adsorption capacity is 2.0-4.0 mg/g. Mesopores are the main pores in Chang 7 shale, macropore and micropores come second, and nano scale pores are also developed, which indicates that the shale reservoir have good adsorption capacity. This study can provide theoretical basis for the further shale gas resource evaluation.

Key words: Chang ₄₊₅ oil reservoir set, hydrocarbon forming conditions, hydrocarbon form ing mechanism, Linzhen area, Ordos Basin