三角洲前缘储层特高含水后期剩余油分布特征

Residual Oil Distribution Features in Delta Front Reservoir during Late Period of Super-high Water Content

以东营凹陷胜坨油田沙二段81层三角洲前缘储层为例,利用岩心分析资料以及剩余油饱和度测井资料,系统揭示了储层原始含油性以及特高含水后期的剩余油分布特征。研究表明,三角洲前缘储层具有反旋回垂向层序和反韵律物性分布特征,由此控制储层原始含油性也具有反韵律特征。特高含水后期,受储层内部结构、级差与重力因素综合影响,剩余油具有3种分布状态和3种分布类型。三角洲前缘储层水驱过程相对均衡,近残余油态、过渡态、差异分布、均匀分布类型的剩余油在特高含水后期剩余油分布中占数量优势,单一成因砂体侧向边界与四级界面耦合形成的侧向遮挡区域水驱程度相对较低,存在小规模的剩余油富集区。

Taking delta front reservoir in Layer 81 of Sha2 member in Shengtuo Oilfield in Dongying Sag as the example,core analysis data and residual oil saturation logging data were used to systematically identify original oil-bearing properties and residual oil distribution features in this reservoir during late period of super-high water content. The results indicate that the delta front reservoir is characterized by anti-cycle vertical sequences and anti-rhythmic physical properties,and thereby the controlled original oil-bearing properties are also anti-rhythmic. During late period of super-high water content,affected by comprehensive internal reservoir structure,level difference and gravity factors,the residual oil is distributed in three statuses and three types. Water flooding process in delta front reservoir is relatively balanced,peri-residual oil state,transition state,differential distribution and uniform distribution occupy quantity predominance in residual oil distribution during late period of super-high water content; the coupling between lateral boundary of sand bodies with single genesis and fourth order boundary forms lateral barrier region. Water flooding degree is lower,with small-scale enriching areas of the residual oil.