Nanoscale Pore Changes in a Marine Shale: A Case Study Using Pyrolysis Experiments and Nitrogen Adsorption

Abstract

Nanoscale pores have an important role in the accumulation of gas in shale gas reservoirs. Indeed, the formation of nanopores is critical for the characterization and evaluation of a shale reservoir. Moreover, the effect of pyrolysis on the modification of nanopores is not clear. Therefore, this paper focuses on pyrolysis and nitrogen adsorption experiments to examine the nanoscale pore structure and evolution in marine shale strata with low total organic carbon content. All of the examined samples contain micro-, meso-, and macropores. The results show that the number of micropores increased as a result of artificial maturation (i.e., pyrolysis), which resulted in a significant increase in the surface area and the total pore volume. The openness of the pores significantly increased when the maturity was higher than 2.5% Ro (vitrinite reflectance). The 1.5–7.5 and 60–70 nm pores are the most pronounced to change after pyrolysis. Furthermore, liquid hydrocarbons produced during heating were shown to influe...