The hydrocarbon in Chang No.8 oil sand,with the Fluorescence of the oil patch-oil immersion in rock cuttings,has been detected in Zhenjing oil field.Through the analysis of the distribution,sedimentary facies and the relative geological characters in Chang No.8 sand,such as the lithological properties,the fracture and the gas measure,the results suggest that the oil test should be carried out in the sands,with the lowest Fluorescence display of the oil patch.The effective thickness of the sands,developed in the favorable sedimentary facies and,are more than 10m.Meanwhile,the sands possessed the excellent assemblage of the fracture.