胜利油田孤岛油区馆陶组上段沉积结构单元

结构单元分析法(Architectural-Element Analysis)作为一种比较成熟的研究方法,已广泛应用于古代河流沉积研究.本文首次根据钻孔资料分析胜利油田孤岛油区馆陶组上段5～1+2砂层组河流沉积的结构单元.该段5～1+2砂层组岩石类型简单,可分为11个岩相类型.根据界面特征、岩相组合、内部几何形态、外部几何形态和垂向剖面特征等划分出6个结构单元:河道滞流沉积(CHL)、侧向加积砂坝(LA)、天然堤(LV)、决口扇(CS)、决口水道(CR)和洪泛平原细粒(FF).其中洪泛平原细粒(FF)、决口扇(CS)和侧向加积砂坝(LA)结构单元最为发育,其次是天然堤(LV)和决口水道(CR)结构单元,而河道滞流沉积(CHL)结构单元则不甚发育.决口扇(CS)结构单元是馆陶组上段砂体发育的主要单元之一,且富含油气资源.因此,进一步加强决口扇的研究对油气资源的勘察是十分必要的.

SEDIMENTARY ARCHITECTURAL ELEMENTS OF UPPER MEMBER OF THE GUANTAO FORMATION IN GUDAO AREA, SHENGLI OILFIELD

Architectural element analysis advanced by Miall, as a relative common method, has been extensively applied on studying ancient fluvial deposits in the world. Based on the drill data, this paper studied, firstly, the architectural elements of fluvial deposits of the 5～1+2 sandstones in the Upper Members of Guantao Formation (UMGF) in the Gudao area, Shengli Oilfeild. There are 11 kinds of petrofacies in the 5～1+2 sandstones of the UMGF, with simple rock association. On the basis of bounding surface features, petrofacies assemblage, internal geometry, external form and vertical profile, etc., the sandstones can be divided into 6 architectural elements, namely, the channel lag (CHL), the lateral accretion macroform (LA), the levee (LV), the crevasse splay (CS), the crevasse channel (CR) and the floodplain fines (FF), in which the architectural elements of FF, CS and LA develop extensively, the LV and CS occur subordinately, and the CHL develops poorly. The crevasse splay element is one of architectural elements which, as a main unit of sand bodies in the UMGF, contains rich oil and gas. It is necessary to make more study on the element of crevasse splay for exploration of oil and natural gas.