According to litho-chemical index and microscopic features

the buried hill in JZS oilfield can be divided vertically from top to bottom into three zones with different levels of chemical weathering:weathered

semi-weathered and un-weathered zones.Similarly

based on core observation

thin section analysis and image logging and in combination with production logging data

it also can be divided into three zones from surface to core:weathered crust

semi-weathered crust and basement

corresponding to the three chemical weathering levels respectively.The reservoir space of buried hill is dominated by structural fractures in semi-weathered crust and the solution fractures in weathered crust.The development of fracture reservoir is controlled by multiple factors such as lithology

tectonic movement

weathering and dissolution

of which tectonic movement is the main controlling factor.According to the timing of faults and their dip angle

the structural fractures of buried hill in JZS can be grouped into four types:early semi-filled/filled horizontal fracture

early semi-filled/filled vertical fracture

late semi-filled cataclastic fracture and late open slant fracture.By using crude oil inclusion detection technique

we recognized that the main effective fracture types of the buried hill in JZS are late semi-filled cataclastic fracture and late open slant fracture.We also established criteria for identifying effective fractures with conventional logging data calibrated by core and image logging data and restructured a new effective structure identification curve for fractured reservoir inversion and distribution prediction.Application shows that the prediction results of this method correlate well with that of other geophysical methods.This method provides the neccesary geological basis for development well emplacement.