Table 3: Argillite cap types of Paleogene-Neogene strata in thevertical direction.

Types Depth(m) Features Sealing capacity
Class I <1000 high porosity, plastic fault transformation cap combination zone Good
Class II 1000-2000 medium porosity, elastoplastic fault transformation cap combination zone Better, locally worse
Class III >2000 low to ultra-low porosity, fracture transformation cap to rupture fault transformation cap combination zone Good or bad