Pore characteristics and adsorption capacity of Chang 7 shale of Yanchang Formation in the southeastern Ordos Basin

  • XIA Jia ,
  • DUAN Yi ,
  • GAO Yuan ,
  • ZHANG Xiaoli ,
  • HE Jinxian ,
  • XU Li
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  • 1. Key Laboratory of Petroleum Resources, Gansu Province/Key Laboratory of Petroleum Resources Research, Institute of Geology and Geophysics, Chinese Academy of Sciences, Lanzhou 730000, China; 2. University of Chinese Academy of Sciences, Beijing 100049, China

Online published: 2016-11-10

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.

Cite this article

XIA Jia , DUAN Yi , GAO Yuan , ZHANG Xiaoli , HE Jinxian , XU Li . Pore characteristics and adsorption capacity of Chang 7 shale of Yanchang Formation in the southeastern Ordos Basin[J]. Lithologic Reservoirs, 2016 , 28(6) : 30 -35 . DOI: 10.3969/j.issn.1673-8926.2016.06.005

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