远源砂质辫状河储层构型及控制因素——以秦皇岛32-6油田为例

Architecture analysis and controlling factor on far source sandy braided river reservoir-A case study of Qinhuangdao32-6 oilfield

秦皇岛32-6油田NmⅡ_(2-4)小层属于远源砂质辫状河储层,依据Maill河流构型分类方案对其进行构型单元的划分,并分析各级构型单元的成因、特征、识别方法和拼接关系。5级构型单元为整个辫状河道;4级构型单元包括河道、心滩及河漫滩3个微相级单元,纵向上存在河道-心滩-河漫滩、河道-河道、河道-心滩-河道和河道-心滩-河漫滩-河道4种拼接方式,横向上存在河道-心滩、河道-河漫滩和心滩-河漫滩3种拼接方式;在3级构型单元划分中,把河道单元划分为河底高能滞留单元、下部高能充填单元、中部加积单元及顶部低能废弃单元4个单元;心滩划分为垂积体和落淤层2个单元,河道单元内部的4个3级构型单元在纵向上有滞留-充填-加积-废弃-滞留型、滞留-充填-加积-滞留型、滞留-充填-滞留型3种拼接模式;心滩单元垂积体间的接触关系分为接触型和隔离型2类。储层构型特征的控制因素主要包括地形条件、水体能量及物源供给量、沉积基准面升降和构造运动。

Nm Ⅱ_(2-4)layers in Qinhuangdao32-6 oilfield are a set of far source sandy braided river reservoirs. According to river configuration classification scheme of Maill,the architecture of the braided river reservoir was analyzed. The genesis,characteristics,identification methods and the superposed pattern of all levels of configuration units were discussed. The fifth level configuration unit is the whole braided river;the fourth level configuration unit consists of three microfacies which are channel,channel bar and floodplain,and four kinds of vertical superposed models were proposed as channelbar-floodplain,channel-channel,channel-bar-channel and channel-bar-floodplain-channel,while three kinds of horizontal contact model were described as channel-beach,channel-floodplain and beach-floodplain. For the third level configuration unit,the channel was divided into bottom energy retention unit,high energy filling unit,accretion unit in the central part and waste low energy filling unit on the top of the channel. The channel bar was divided into vertical accretion body and off silt layer. Three superposed models of the third level configuration unit within the channel are retention-filling-accretion-waste-retention,retention-filling-accretion-retention and retention-filling-retention. The contact relationships of the vertical accretion bodies were divided into contact type and isolation type. The controlling factors of the configuration characteristics are terrain conditions,water energy,provenance supply,the ascending-descending of base levels and tectonic movements.