川西新场地区三叠系须家河组五段层序地层与沉积体系研究

发布时间：2018-12-14 19:36

【摘要】：本文运用高分辨率层序地层学、沉积岩石学等理论,以区域地质、钻/测井与地震剖面资料分析为基础,综合岩心、野外剖面资料,通过对新场地区三叠系须家河组五段单井测井、地震层序分析,确定新场须五段高分辨率等时层序地层格架方案,并将砂体及沉积体系置于层序地层格架内,以中期旋回为单元研究其时空展布特征,最终建立新场须五段沉积模式,预测有利储集相带,从而为新场须五段储层勘探开发提供理论基础。新场须五段自上而下划分为1个长期基准面旋回、3个中期基准面旋回,9个短期基准面旋回。3个中期旋回对应于上、中、下三个亚段,9个短期旋回对应9套砂组。新场须五段基准面旋回层序结构可归纳为三种类型,A类向上“变深”非对称旋回;B类向上“变浅”非对称旋回;C类对称旋回。短期旋回结构具有多样性,3种旋回结构均发育,A类多发育于下亚段,B类多发育于须五上亚段,C类则多发育于须五中亚段;中期旋回结构发育C1型和C2型旋回结构,长期旋回仅发育C1型旋回结构,即向上“变深”旋回大于向上“变浅”旋回,反映须五段沉积演化经历了缓慢湖进-快速湖退的过程。结合测井、岩心、露头资料对须五段进行相标志分析、测井相及单井相分析,确定新场须家河组五段以浅水湖泊-三角洲沉积体系为特征,划分出三角洲前缘以及滨浅湖2种沉积亚相,水下分流河道、分流间湾、河口坝及滨浅湖泥、砂泥坪、滩坝等6种沉积微相。选取中期旋回层序为等时地层单元进行沉积相平面展布特征研究,上、下亚段以三角洲前缘河道砂沉积为主,中亚段主要为以粉砂为主的滨浅湖滩坝相。须五段沉积时期的沉积模式为三角洲一湖泊沉积模式,北部西部距物源近,多发育河道砂,向南水体加深,逐渐相变为滨浅湖。综合须五段沉积相和高产岩性组合分析,水下分流河道为须五段储层发育的有利相带。
[Abstract]:Based on the theories of high resolution sequence stratigraphy and sedimentary petrology, based on the analysis of regional geology, drilling / logging and seismic profile data, the core and field profile data are synthesized in this paper. Based on the single well logging and seismic sequence analysis of the fifth member of Xujiahe formation of Triassic system in Xinchang area, the high resolution isochronous sequence framework scheme of the fifth member of Xinchang formation is determined, and the sand body and sedimentary system are placed in the sequence stratigraphic framework. The spatial and temporal distribution characteristics of Xinchangxiu formation are studied by taking the intermediate cycle as the unit. Finally, the sedimentary model of the five member of Xinchangxiu formation is established, and the favorable reservoir facies zone is predicted, thus providing a theoretical basis for the exploration and development of the reservoir in the fifth member of Xinchangxiu formation. The five segments should be divided from top to bottom into one long-term datum cycle, three medium-term datum cycles, nine short-term base-level cycles, three medium-term cycles corresponding to the upper, middle and lower subsections, and nine short-term cycles corresponding to 9 sets of sand sets. The sequence structure of the five-member base-level cycle in the new field can be divided into three types: type A upward "deepening" asymmetric cycle, category B upward "shallow" asymmetric cycle, and class C symmetric cycle. The structure of short-term cycle is diverse, the three cyclic structures are all developed, A is more developed in the lower submember, B is more in the upper part of Xuzhou, and C is in the middle part of Xuzhou. The middle cycle structure developed C1 type and C2 type cycle structure, while the long term cycle only developed C1 type cycle structure, that is, the upward "deepening" cycle is larger than the upward "shallow" cycle, which reflects that the sedimentary evolution of the fifth member of Xuzhou has experienced the process of slow lacustrine advance and rapid lake regression. Combined with logging, core and outcrop data, facies marker analysis, logging facies and single well facies analysis of Xufive member are carried out. It is determined that the five member of Xinchang Xujiahe formation is characterized by shallow water lacustrine delta sedimentary system. Six sedimentary microfacies, such as delta front and shallow lake, underwater distributary channel, interdistributary bay, estuarine dam and shallow lake mud, sand flat and beach dam, are divided into six sedimentary microfacies. The distribution characteristics of sedimentary facies are studied by selecting the intermediate cyclic sequence as isochronous stratigraphic unit. The upper and lower substrata are mainly composed of delta front channel sand and the middle part is mainly silty shoreline beach and dam facies. The sedimentary model of Xuwu formation is delta-lake sedimentary model. The north west is near to the source of material, the river channel sand is developed, the water body deepens to the south, and the facies is gradually changed into a shore-based shallow lake. According to the analysis of sedimentary facies and high-yield lithology combination of Xuwu formation, the underwater distributary channel is a favorable facies zone for reservoir development of Xuwu formation.
【学位授予单位】：中国地质大学(北京)
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P618.13;P539.2

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