埕岛油田沙三段储层沉积学特征

Characteristics of Reservoir Sedimentology in the Sha-3(1) Member of Chengdao Oilfield

沙三1 段是埕岛油田重要储集层之一 ,其储集层岩石学特征研究对该油田的滚动开发及勘探选区评价具有十分重要的指导意义。本文研究了沙三1 段储层沉积特征。研究认为 :⑴沙三1 段储集层为一套粗碎屑沉积岩 ,属河流 -滨浅湖沉积体系辫状河三角洲相 ,⑵块状层理粗砂岩相、槽状交错层理中细砂岩相、波状交错层理细砂岩相和平行层理细砂岩相为最有利的油气储集岩石相 ;Sf→Mm相组合、Sm→Mm相组合、St→Mm相组合以及Sr→Sh相组合是最发育的岩石相组合类型 ,也是最有利油气储集的岩石相组合 ,⑶物源方向主要为北东和西南 ;沉积相展布受构造控制 ,呈北北西 -南南东方向展布 ;沉积面貌具有西高东低。

Based on the study of characterislies of reservoir petrology and sedimentology in target strata,the authors have put forward that the depositional environment of the Sha-3 member is river-shore shallow lake environment,the sedimentary system belongs to lakeshore depositional system,and the sedimentary facies of the reservoir are braided river delta facies. The Sha-3(1) member is one of the most important reservoirs in Chengdao oilfield,sedimentary characteristics of which are very important for the rolling development and the evaluation of prospecting areas.The study concludes:(1) The reservoir of Sha-3(1) member is a set of coarse grain detrital sediment,belonging to river-shallow lake side depositional system with hraided river delta facies.(2)Massive gritstone,trough cross-stratification fine-middle sandstone,wave cross-stratification fine sandstone and parallel-stratification fine sandstone are the most favourable petrofacies for petroleum accumilation;The combinations of Sf→Mm,Sm→Mm,St→Mm and Sr→Sh are the most developed petrofacies combination type,and also the most favourable for petroleum accumulation.(3)The sedimentary derivation is mainly northeast and southwest. The strelch of sedimentary facies,which is under control of leetonics,goes north-northwest and south-southeast. The sedimentary province is geographically high in the west and low in the east,and high in the south and low in the north.