Mechanical-Chemical-Mineralogical Controls on Permeability Evolution of Shale Fractures

Figure 5

Effective hydraulic aperture evolution with time under different fluid acidity conditions for various shales. (a) Longmaxi shale, (b) Green River shale, and (c) Marcellus shale. When fluid pH = 4.0 and 5.0, there is a monotonic increase in effective hydraulic aperture until a maximum aperture is observed for Longmaxi shale and Green River shale. The effective hydraulic aperture keeps a decrease trend for Longmaxi shale and Green River shale when pH = 6.0 and 7.0 while all fluid acidity conditions for Marcellus shale.

(a)

(b)

(c)