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古龙南英台地区葡萄花油层沉积体系研究
Sedimentary System Research on Putaohua Oil Layer of Yingtai Area in the South of Gulong
【作者】 陈红;
【导师】 钟建华;
【作者基本信息】 中国石油大学 , 地质学, 2011, 硕士
【摘要】 古龙南英台地区位于松辽盆地北部中央坳陷区齐家—古龙凹陷南部,研究的目的层段是下白垩统的葡萄花油层,即姚家组一段。前人对本研究区的地层、沉积相等方面已经做过不同程度的研究,但存在不同的见解。本文在前人研究的基础上,以层序地层学、沉积学等理论为指导,对葡萄花油层进行了更加精细的层序划分,在此基础上进行了相应的沉积体系研究,对该区的储层预测及有利油气富集区优选具有重要的指导意义。综合地震、测井、岩心、录井等资料,重新厘定了研究区葡萄花油层所属的三级层序边界SBⅢ1和SBⅢ2,分别对应地震反射界面T1-1和T03;在此基础上,又依次识别出英台地区葡萄花油层的四级、五级、六级层序界面。进而对研究区进行了高分辨率层序地层划分,将葡萄花油层划分为1个中期旋回(PI油组)、3个短期旋回(PI上、PI中、PI下)和8个超短期旋回(PI1、PI2、PI3、PI4、PI5、PI6、PI7、PI8)。在各级次基准面旋回划分的基础上,以超短期旋回为等时地层对比单元,对研究区进行了层序地层对比,建立了英台地区葡萄花油层的层序地层格架。在此层序格架内进行了物源分析、沉积相类型及沉积相展布研究。通过颜色、岩性、沉积构造类型、古生物标志、测井相特征等相标志的研究,结合岩心观察和电性资料,进行了详细的单井沉积相分析。在此基础上,确定了研究区的沉积相类型,认为研究区葡萄花油层发育三角洲相和湖泊相,三角洲相以三角洲前缘亚相沉积为主,主要发育水下分流河道、河口坝、席状砂、水下决口扇和水下分流间湾等微相;湖泊相主要发育滨浅湖相。通过重矿物分析、砂岩百分含量等值线图的综合判定,认为研究区主要受西部物源控制,北部物源为次要物源,母岩类型主要为酸性岩浆岩。在以上研究的基础上进行了剖面相对比,并编制了以超短期旋回为单位的8张沉积相平面展布图,揭示了该区沉积体系的时空展布规律,综合分析认为研究区葡萄花油层沉积时期整体为水体加深,砂体萎缩的退积沉积序列。
【Abstract】 The first member of Yaojia Formation, Putaohua Reservoir of the lower cretaceous, is the study layer of Yingtai area in South Gulong Region, locating in southern part of Qijia-Gulong sag of the central depressed area of Songliao basin. Although predecessors have done much deeply research on this area, different opinions are still existing. Based on the former studies, guided by the theories of sequence stratigraphy, sedimentology, this dissertation did a more specific division and facies reserch on Putaohua Reservoir, which is very instructive to the reservoir prediction and favorable abundance zone of oil and gas.Based on seismic, well log, core and geologic log data, third-order sequence boundaries SBⅢ1and SBⅢ2 corresponding to seismic reflection interfaces T1-1 and T03 were redelimited; extending the method turing on it and developing it into forth-order, fith-order and sixth-order sequence boundaries of Putaohua Reservoir in Yingtai area. And then, high resolution stratigraphic classification was conducted, with one mid-term cycles ( PI reservoir group), three short-term cycles ( PI upper, PI middle, PI lower ) and eight super-short-term cycles(PI1、PI2、PI3、PI4、PI5、PI6、PI7、PI8). Through the division of base level cycles and sequence stratigraphic units (super-short-term cycles), sequence stratigraphic contrast and sequence stratigraphic framework of Putaohua Reservoir of Yingtai area was accomplished.Source analysis, sedimentary facies types and distribution of sedimentary facies were researched within sequence framework. By means of analyzing color, lithology, types of sedimentary structures, paleontological markers, electrofacies feature and so on ,combined with core and logging data, single well facies, we did a comprehensive study on single well facies, and then confirmed types of sedimentary faces in the study area which develops delta facies and lake facies in Putaohua oil layer. Delta front subfacies is the main subfacies, of which microfacies types mainly are underwater distributary channel, mouth bar, sand sheet, sub-sea crevasse channel and underwater distributary interchannels. Lake facies mainly develops shore-shallow lake microfacies. Heavy minerals data and sandstone content revealed that controlled mainly by the western provenance system and accidentally by the northern provenance system, source rock of this study area is mainly acidic magmatic rocks. On the basis of the study above, profile contrast were implemented and eight phase-plane diagrams in super-short-term cycle units were drawed, which established the time and space evolution of sedimentary system of this area. What we have achieved makes us believe that Putaohua reservoir deposits in a deepening water, sand body fading retrograding sedimentary sequence.
【Key words】 Sedimentary system; Sequence stratigraphy; Putaohua reservoir; Yingtai area;