南海莺歌海盆地黄流组海底扇储层构型特征*

南海莺歌海盆地东方X气田中新统黄流组一段发育浅海海底扇沉积,沉积类型特殊,砂体连通性复杂,对储层构型的研究较为薄弱,影响了该地区的油气勘探和开发。以层序地层学、沉积学、测井地质学、地震沉积学等理论为指导,结合岩心、钻井、测井、三维地震和地震波阻抗反演成果等资料,对东方X气田中新统黄流组一段Ⅱ_b气组海底扇构型单元及砂体分布规律进行研究。结果表明: 研究区海底扇主要发育中扇亚相的水道沉积、堤岸沉积、席状砂和扇缘砂; Ⅱ_b气组以水道沉积及席状砂为主,2期水道沉积以充填沉积作用为主,整体呈NW-SE向展布;储集层内部砂体有层状充填、垂向切叠及侧向切叠3种叠置样式; 储层构型主控因素包括物源供给、地形坡度及重力流能量。

Reservoir architecture of the Huangliu Formation submarine fan in Yinggehai Basin,South China Sea

Submarine fan on shallow shelf are developed in the Member 1 of the Miocene Huangliu Formation in the Dongfang X Gas Field of the Yinggehai Basin. The sedimentary type in this area is special,and the sand body connectivity is complicated. The research on reservoir architecture of submarine fan is relatively weak,which seriously affects the oil and gas exploration and development in the Dongfang X Gas Field. Under the guidance of sequence stratigraphy,sedimentology,logging geology,seismic sedimentology and other theories,and based on the data of core,drilling,logging,3D seismic and seismic wave impedance inversion,the architecture and sandbody distribution pattern within the submarine fan in this area are studied. The results show that: Submarine fan in the study area is mainly middle fan and characterized by the channel,levee,sheet sand and fan margin sand deposits;Channel and sheet sand are common in the II_b gas group of the first member of the Huangliu Formation. Channels are dominated by sedimentation process and can be divided into two stages of development,which are oriented in NW-SE direction;There are three stacking patterns sand body within the reservoir,layered filling,vertical cut-stacking and lateral cut-stacking;The controlling factors of reservoir architecture include the sediment supply,the slope gradient and the energy of the gravitational flow.