The Chang-2 reservoir of Ansai oilfield has the geological characteristics of low porosity

low permeability

fast change of physical properties and strong vertical and horizontal heterogeneity. Based on the

''

four properties

''

relation of reservoir

we established the minimum standards of effective thickness by using the core analysis

oil test

production dynamics and logging by the way of histogram method and cross plot method. Then we proposed the different types of interlayer logging quantitative identification chart and the elimination criterion of various interlayer on the basis of the semi-quantification and semi-qualitative analysis by

many kinds of logging curves. The minimum values were as follows: the oil-bearing property was to see the grease spots; the lithological property was to see the fine-grained sandstone; the physical property were the porosity was more than or equaled to 11.5 % and the permeability was more than or equaled to 0.63×10

-3

μm

2

; the electrical property were the resistivity was more than or equaled to 13 Ω·m and the acoustic was more than or equaled to 230 μs/m. The main types of interlayer were calcareous interlayer and muddy interlayer. We could identify and eliminate the interlayer by the quantification of curves of natural gamma

acoustic and microelectrode

and the qualitative analysis of the curves of spontaneous potential

RILD

RILM

microsphere resistivity and micronormal.