The 2nd member of Shahejie Formation in He 43 block is divided into 5 flow units according to productivity index per meter of single layer production during water-free oil production period

distribution characteristics and the corresponding characteristics of air-permeability and relative permeability. Permeability of type Ⅰ flow unit is the best

that of type Ⅱ is relatively good

type Ⅲ medium

type Ⅳ relatively poor

and type Ⅴ poor. Laterally

the major subzones with thickness of over 3.5m are mainly of type Ⅰ

Ⅱ and Ⅲ flow units

while the non-major subzones with thickness of less than 3.5m are mainly of typeⅣ and Ⅴ flow units. Vertically

the distribution of flow units are complex

and even all of the five types of flow units can exist concurrently in a single well. This characteristic shows that the reservoirs in the 2nd member of Shahejie Formation in He 43 block have strong heterogeneity. Different flow units have different relative permeability characteristics. Oil-phase relative permeability in flow units with good poroperm characteristics decline slowly

while water-phase relative permeability goes up quickly. On the contrary

oil-phase relative permeability declines quickly

while water-phase relative permeability goes up slowly.