渤海A油田明化镇组下段河-坝砂体储层构型及剩余油分布

Reservoir architecture and remaining oil distribution of channel-bar:a case from lower Minghuazhen Formation in Bohai A oilfield

渤海A油田新近系明化镇组下段为鸟足状浅水三角洲沉积,平面上不同期次河-坝砂体频繁切叠,形成复杂的空间结构样式,极大地制约了油田的开发效果。以沉积学理论为指导,综合利用岩心、测井、生产动态等资料,运用储层构型要素分析方法,进行了精细储层构型解剖,明确了储层构型单元空间结构样式,探讨了不同单砂体构型对剩余油分布的控制,并建立了4种剩余油分布模式。结果表明:渤海A油田明化镇组下段河-坝砂体主要发育分离型、叠合型、切叠型等3种垂向接触样式和分离型、拼接型、侧切型等3种侧向拼接样式;剩余油分布研究表明,单砂体内部韵律性、河-坝砂体接触方式及平面非均质性均是剩余油分布的主要控制因素,研究区主要发育"顶部型"、"垂向渗流遮挡型"、"段塞式"和"欠注型"剩余油分布模式,可以分别采用侧钻水平井、厚注薄采、井间加密、井网优化等措施进行剩余油挖潜。该研究成果对海上老油田中高含水阶段的剩余油挖潜具有指导意义。

The lower Minghuazhen Formation of Neogen in Bohai A oilfield is bird-foot shallow water delta deposition. Due to the frequent erosion and superimposition of channel-bar in different periods on the plane,its spatial structure pattern was extremely complex,which greatly restricted the development effect of the oilfield. Under the guidance of sedimentary theory,based on the data of core,well logging and production performance,the fine reservoir configuration was carried out by using the method of reservoir configuration factor analysis. Meanwhile the spatial structure pattern of single sand body configuration units were defined,the control of remaining oil distribution by different single sand body configuration was discussed,and four types of remaining oil distribution models were established. The results show that the single sand body configuration units in the study area mainly develop three vertical contact patterns(such as separation type,superposition type and cutting superposition type)and three lateral splicing patterns(such as separation type,splicing type and side cutting type). In addition,the controls of single sand body configuration on the distribution of remaining oil were analyzed. It is considered that the rhythm within the single sand body,contact model of channel-bar sand body and plane heterogeneity are the main control factors of the distribution of remaining oil. The study area mainly develops"top enrichment","vertical seepage blocking type","plugging"and"under injection type"remaining oil distribution models,and the responding remaining oil potential can be exploited by sidetracking horizontal wells,injecting in thick layers while producing in thin layers,infilling wells and well pattern optimization respectively. The research results have guiding significance for the exploration of remaining oil potential in the middle-high water cut stages of the old offshore oilfields.