南堡1-1区东一段浅水三角洲水下分流河道单砂体叠置关系

Superimposition relationships of the individual sandbody in the shallowwater-delta underwater distributary channel of Member Ed_1 in Block Nanpu1-1

综合应用岩心、测井、生产动态等资料,完成了南堡1-1区东一段储层水下分流河道单砂体的划分。通过总结单一水下分流河道砂体间的接触关系,分析了研究区水下分流河道叠置特征及其形成原因。研究结果表明:南堡1-1区水下分流河道单砂体厚度5. 2～11. 5 m,宽度最大可达400 m;单一水下分流河道砂体在剖面上存在分离式、叠加式、切叠式3种接触关系,以分离式为主;平面上存在分离式、相变式、对接式、切割式4种接触关系,以切割式为主;在空间上可组合成12种基本接触类型,占比由大到小依次为分离+切割、叠加+切割、叠加+对接、切叠+切割等;湖泊水体周期性变化、可容纳空间与沉积物供给通量比值(A/S)、动态地貌形态变化等因素共同形成了研究区浅水三角洲前缘水下分流河道砂体剖面下切能力有限而平面频繁改道交切的特征。

With the help of the comprehensive application of the core, well logging, production performance data and so on, the classification was performed for the single sandbodies in the under-water distributary channel of Member Ed 1 reservoir in Block Nanpu1-1. By means of the summarized contact relationships between the single sandbodies in the underwater distributary channel, the superimposition characteristics and forming causes were analyzed for the channel stated above in the study area. The study results show that the thickness of the single sandbody in the block is in the range from 5.2 m to 11.5 m and the maximal width is 400 m;there are three vertical contact patterns of the single sandbodies, including the separated type, overlap-type and cut-overlay type, the former is the main mode;there are four lateral contact patterns, including the separated type, facies change type, butt-joint type and cut type, the latter is the main type;there are 12 basic contact types in space which can be combined, the occupied proportion from big to small is the separated + cut types, overlap+cut types, overlap+ butt-joint types, cut-overlap + cut types and so forth;periodically changes of the lake body, A/S , dynamic geomorphology are the main factor which altogether make the characteristics of limited low-cutting capacity in the section and frequent diversions in the plane for the sandbodies in the underwater distributary channel of the shallow-water delta front in the study area.