Alkali Effect on Alkali-Surfactant-Polymer (ASP) Flooding Enhanced Oil Recovery Performance: Two Large-Scale Field Tests’ Evidence

Table 2

Reservoir classification [72].

Reservoir classification	Distribution	Monosandbody		Basic reservoirs characteristics
				Effective thickness, H (m)	Permeability, K (mD)	Scale
First-class layer(FCL)	PI group	River sand	Flood plain facies channel sand, highly curved diverting channel sand	≥4 m	≥500	Formation developed with large area, with a width greater than 1000 m
Second-class layer (SCL)	S group and PII group	River sand	Low-bend diversion channel sand, underwater dendritic channel sand	H ≥ 1.0 m	≥100	Formation developed connected with a width greater than 200 m
Nonriver sand H ≥ 1.0 m with oil layer assisted
Third-class layer (TCL)	S group, PII group, and Gao group	Nonriver sand	Thin layer for reserves	H < 1.0 m	<100	Typically formation is sheeted broken like, loose, small size, two-phase mixed staggered distribution
			Nonreserve layer (Biaowai layer)	0	0