三塘湖盆地牛圈湖油田东区侏罗系西山窑组Ⅱ砂组沉积相研究

Sedimentary Facies Study on Ⅱ Sand Group of Jurassic Xisanyao Formation of the East Region of Niujuanhu Oilfield in Santang Basin

针对牛圈湖油田区域沉积微相较复杂，前入沉积相分析过于粗略，且牛圈湖油田东区上产迫切需要精细沉积微相支持的现状，综合运用岩心、测井、录井、地震、岩石薄片等资料，对研究区沉积相进行了深入研究。认为牛圈湖油田东区为辫状河三角洲相．可识别出辫状河三角洲前缘、前辫状河三角洲2种亚相以及5种微相；辫状河三角洲前缘亚相尤其是其中的河口砂坝和水下分流河道微相为最有利区域，是下步上产的主攻潜力区域。通过重矿物及地震资料分析认为牛圈湖油田东区砂体由南、北2个物源控制，南物源起主要控制作用，而非前人认为的北物源。研究区南部发育冲积扇-辫状河-辫状河三角洲-湖泊沉积体系，北部发育辫状河三角洲-湖泊沉积体系。

In view of the situations of complex microfacies of Niujuanhu Oilfield,approximate predecessor's analysis of sedimentation,the support of fine sedimentary microfacies description was badly needed for oil production in the east region of Niujuanhu Oilfield.Through the analysis of core,logging and log data,seismic data and thin rock slice,a fine description was performed on sedimentary facies in the operation area.It is considered that it contains 2 subfacies braided delta front sub-facies and prodelta subfacies and 5 microfacies,of which the channel mouth bar and distributary channel deposit are the most beneficial areas and the potential areas for next oil production.Through heavy mineral and seismic analyses,it is considered that the sand bodies in the region are controlled by north and south sources,especially the south provenance is dominated,which is not mainly of provenance denoted by predecessors.The south of the study area develops alluvial fan facies-braided river-braided river delta-lacustrine facies sedimentary systems,and the north of the study area develops braided river delta-lacustrine facies sedimentary system.