乌石凹陷成藏组合划分及主控因素分析

根据成藏条件把乌石凹陷划分为上、中、下3个成藏组合,不同类型成藏组合具有不同的成藏特征和主控因素。上部成藏组合属于下生上储型,其主控因素是垂向运移条件和盖层条件;中部成藏组合属于自生、自储、自盖的源内成藏,其主控因素是储层条件和流体势;下部成藏组合属于上生下储型,其主控因素是运移条件和储层条件。7号断层下降盘流一段底部砂岩、流二段近岸水下扇以及北部斜坡带垒块分别是乌石凹陷上、中、下成藏组合的有利勘探目标。

Hydrocarbon play division and major control analysis in Wushi sag, Beibuwan basin

According to hydrocarbon accumulation conditions,Wushi sag can be divided into three plays,i.e.Upper,Middle and Lower plays,which are characterized by different accumulation features and major controls.For Upper play,hydrocarbon is generated from lower source rocks and accumulates in upper reservoir rocks,and its major controls are vertical migration and seal conditions.Middle play can be seen as an "intra-source accumulation" play with distinct properties of self-generation,self-reservoiring and self-sealing,and its reservoir condition and fluid potential are the major controls.Lower play is in a type of upper-generation and lower-reservoiring,and its major controls are migration and reservoir conditions.The favorable exploration targets for Upper,Middle and Lower plays are represented by Liu-1 Member sandstone,Liu-2 Member offshore submarine fan on the downthrow side of Number 7 fault and some horst blocks on the northern slope respectively in Wushi sag.