Study on a New Rock Fracability Evaluation Model of Shale Gas Reservoir

Table 2

Fracture classification table of the pressed core.

Level	Name	The main characteristics
Level I	Main fracture	The longest and widest extension runs through the core, most cores have only one main fracture.
Level II	Secondary fracture	The extension and width are large, but the penetration degree is poor, and there are no symmetrical fractures on the plane graph.
Level III	Branch fracture	The extension and penetration are poor, but have a certain width; it is very obvious in the image. The occurrence is not consistent with the main and secondary fracture.
Level IV	Associated fracture	Small fractures have low extension, penetration, and width.