Mineral Component Identification of Shale Bedding Based on Nano Scratch

The damage morphology and mineral composition were analyzed during the scratch test of Gulong shale using SEM. Using Gaussian function curve-fitting to obtain mechanical from the scratch test, including scratch depth, slope of d²-L curve, and fracture toughness from scratch test, to determine the mineral component content. The results indicate that there is a certain difference between the identification of mineral components based on scratch tests and the results of SEM, which is mainly caused by the heterogeneity of shale itself and the abundance of pores and micro cracks. Although convenient to identify minerals based on scratch depth, this method is difficult to distinguish between cracks and soft organic matter. The accuracy of identifying the slope of the d²-L curve is greatly affected by mineral heterogeneity, and dolomite cannot be accurately identified in the distribution areas of plastic minerals and brittle minerals. The fracture toughness-based method avoids the influence of pores and cracks, and the identification results of minerals are relatively close to the mineral content of SEM.