The Visual and Quantitative Study of the Microoccurrence of Irreducible Water at the Pore and Throat System in a Low-Permeability Sandstone Reservoir by Using Microcomputerized Tomography

Table 3

Classification of microcharacteristics of irreducible water in the pore and throat system.

Unit	Irreducible water patterns	Shape factor ranges	Range of saturation of irreducible water in a single pore or throat
Pore system	Conglobation	< 0.1	90 <  < 100
	Cluster	0.1 <  < 0.2	30 <  < 90
	Water film	0.2 <  < 0.4	10 <  < 30
Throat system	Curved piece-necking	< 0.2	90 <  < 100
	Slug-filling	0.4 <  < 0.7	30 <  < 90
	Water film	0.2 <  < 0.4	10 <  < 30