Experimental Study on the Self-Healing Behavior of Fractured Rocks Induced by Water-CO₂-Rock Interactions in the Shendong Coalfield

Figure 5

Micromorphologies of feldspar crystals at the fracture surface in the coarse-grained sandrock specimen before and after the experiment. (a) Potassium feldspar crystals (before the experiment). (b) Corroded potassium feldspar crystals (after the experiment). (c) Albite crystals (before the experiment). (d) Corroded albite crystals (after the experiment). Note: to confirm the mineral composition in the areas marked by the rectangles, an energy dispersion spectrum (EDS) analysis was performed, and the results are presented in the tables below the SEM images (the same below). In the tables, Wt% means weight percentage, At% means Atomic percentage, and the same below.

(a)

(b)

(c)

(d)