Evolution of pores in shale during thermal maturation using Small Angle X-ray Scattering (SAXS)

Nano pores in shale were measured quantitatively using a Small Angle X-ray Scattering (SAXS) method in this study. The volume fraction and distribution function of open and closed pores in the range of miro-pore and meso-pore were obtained in a quick measurement. To quantitatively analyze pore evolution in shale during thermal maturation, some artificial pyrolysis residues of different temperatures and some natural core samples were obtained for SAXS pore measurement. Results show that with the increase of thermal maturity, pore abundance becomes higher. From 300℃ to 600℃, pore width can increase by 35% without considering formation compaction. It is inferred that mature and over-mature shale can develop abundant organic pores, which are advantageous for shale gas storage.