Abstract:

Based on sedimentology and high resolution sequence stratigraphy, lithology and physical property characteristics of shoreline-tidal reservoirs of Lower Zhujiang Member and Zhuhai Formation in block A of Huizhou depression, Pearl River Mouth Basin, were discussed by the observation of thin sections and SEM, the analysis of logging and geochemistry, and so on. Most of deposits of Zhuhai Formation are formed in tidal environment, and the main rock type is lithic subarkose; most of deposits of Lower Zhujiang Member are formed in shoreline environment, and the main rocks type is lithic arkose, and shoreline deposits with less mud, were well developed in western area; tidal deposits with more mud, were well developed in the eastern area. According to the observation of thin sections and SEM, and experimental analyzing data, primary intergranular pores are the major pore types in reservoirs. The ratio of primary pores in the west is higher than that in the east, the physical property in the west is better than that in the east, and the physical property of shoreline deposits in Lower Zhujiang Member are better than that of tidal deposits in Zhuhai Formation. With the analysis of digenesis, it is regarded that depositional environments, controlled by base level cycle frameworks, is a major controlling factor in reservoir physical properties. Meanwhile, for the depositional system of shoreline and tide, the physical property, from foreshore-lower shorefaceupper shoreface-intertidal sand flat-subtidal channel-intertidal mixed flat-intertidal channel-subtidal sand bar to supratidal mud flat, gradually becomes worse, and the physical property of shoreline sands is superior than that of tidal sands.
             

Key words:  Huizhou depression, Lower Zhujiang Member, Zhuhai Formation, shoreface deposits, tidal deposits, physical property evaluation