珠江口盆地惠州凹陷A区块珠江组下段和珠海组滨岸—潮汐沉积储层特征及物性评价

以沉积学和高分辨率层序地层学理论为基础,通过薄片、扫描电镜观察、测井和地球化学分析等手段,对珠江口盆地惠州凹陷A区块珠江组下段和珠海组滨岸—潮汐沉积储层岩性和物性特征进行研究,该区珠海组以潮汐沉积为主,岩性主要为岩屑质长石砂岩;珠江组下段以滨岸沉积为主,岩性主要为岩屑质亚长石砂岩,西部滨岸沉积发育,岩性较纯,东部潮汐沉积发育,砂泥混杂。储层孔隙类型以原生粒间孔为主,其中西部原生孔隙所占比例较东部高,西部地区物性较东部好,珠江组下段滨岸沉积物性较珠海组潮汐沉积高。结合成岩作用分析,认为该区储层物性主控因素为基准面旋回格架内的沉积环境,同时针对滨岸和潮汐沉积体系,由前滨—上临滨—潮间潮砂坪—下临滨—潮下潮道—潮下潮砂坝—潮间混合坪—潮间潮道—潮上泥坪物性逐渐变差,且滨岸砂岩物性优于潮汐相的。

Characteristics and Physical Property Evaluation of Shoreline-Tidal Depositional Reservoirs of Lower Zhujiang Member and Zhuhai Formation in Block A of Huizhou Depression, Pearl River Mouth Basin

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.