The Paleogene strata are constituted of Wenchang, Enping and Zhuhai Formations in Huizhou Depression. Deep reservoirs are in Enping and Zhuhai Formations. The reservoirs mainly consist of secondary porosity such as intergranular and intragranular dissolved pores, and clay mineral micropores as well as residual primary intergranular pores and fissures, among which the average primary porosity is 2.4, (accounting for 22.2, of the total porosity), the average secondary porosity is 5.6, ( 65.2, of the total) and the average fissure porosity is 1.0, (12.5, of the total). Development of secondary porosity improved the reservoir capacity of deep sandstone due to dissolution of organic acid to skeleton grains and matrix in sandstone. The secondary porosity developed well in a depth range of 3500~4200 m where reservoir property is good but the secondary porosity is obviously decreased in the depth of 4200~4500 m due to the late recementation and compaction. argin but TypeⅡand TypeⅢ in the Northwest Shelf of Australia, Mid-Norway continental shelf and South Sea.