鄂尔多斯盆地安塞地区长6油层沉积相研究

Study on the sedimentary facies of Chang 6 oil layer in Ansai area of Ordos Basin

文章选取长6油层组这一典型的曲流河三角洲作为例案,分析该地区发育的微相类型:水上分流河道、分流间沼泽、水下分流河道、河口坝、分流间湾等,其中以三角洲前缘水下分流河道为主。研究表明了相是沉积物形成条件的物质表现。(1)曲流河三角洲平原弯度大的分流河道与平原相近,分流河道许多向外延展;(2)曲流河三角洲前缘水下分流河道河道短,由于水体浅所以导致了大量的堆积物沉积,河口处冲击力变大,水携带者冲积物缓慢运移,多在水下分流河道的两侧堆积成指状;(3)受曲流河三角洲平原的影响,在其末端垂向沉积上,上粗下细在沉积粘土沉积之上,形成河口坝等厚度的砂体富集体。在沉积相砂体展布中体现了砂体长61发育最强,对于长6油层的开发有指示意义。

In order to understand the sedimentary characteristics of the chang 6 reservoir Delta,this point is proved by using cores,logging curves,sedimentary facies markers,sediment data,etc. A large number of studies have been conducted on the characteristics and sedimentary patterns of the curved river delta at home and abroad. It is difficult to achieve unity in the lack of subtle research on this area. Therefore,this paper takes the case of Chang 6 oil reservoir group,a typical curved river delta,as an example to analyze the microphase types of development in the area. The water diversion river,the diversion swamp,the underwater diversion river,the estuary dam,the diversion bay,among which the delta front edge is mainly the underwater diversion river. The study shows that the phase is the material manifestation of the sediment formation conditions. First,the diversion channel with a large bend in the plain of the Curving River Delta is similar to the plain,many diversion channels extend outwards,and second,the water diversion channel on the front edge of the Curving River Delta is short. Due to the shallow water body,a large number of deposits have been caused,the impact at the estuary has become larger,and the slowly moving of alluvial water carriers has accumulated mostly on both sides of the underwater diversion channel. Third,it is affected by the plain of the curved river delta. On the vertical deposition,The upper and lower thicknesses are fine on the sedimentary clay deposits,forming a estuary dam,forming an equal thickness sand body rich group. In the sedimentary facies,the sand body 61 shows the strongest development,which is of great significance to the guiding length of 6 oil layers.