辽东湾坳陷新近系馆陶组浅水三角洲的发现及其油气勘探意义

发布时间：2018-09-13 08:35

【摘要】：为突破辽东湾坳陷新近系馆陶组沉积相的早期认识对该区油气勘探下一步进展的制约,以沉积地质、地球物理和古生物相结合的分析方法,详细分析了湖泊及浅水三角洲存在的地质背景和证据。通过辽河坳陷馆陶组和明化镇组下段的沉积模式及可可西里卓乃湖-库赛湖区的现代沉积比较,结合孢粉百分含量法和相对比值法的半定量分析方法所揭示的古湿度和古温度分析结果,认为馆陶组主要是亚热带且湿度逐渐增大的气候条件下,以冲积扇和辫状河为主,具有大平原小前缘特点的浅水三角洲沉积模式。三角洲平原分为以冲积扇为主的上平原和以辫状河为主的下平原,三角洲前缘具有平面规模小、不稳定、河口坝和远砂坝不发育的特征。馆陶组下段封闭型湖泊面积小,以三角洲平原沉积为主;馆陶组上段湖域面积扩大,三角洲前缘更加发育,且次级洼陷之间由辫状河水系连通,呈敞流型湖泊特征。辽东湾坳陷新近系馆陶组浅水三角洲沉积体系的新认识使得前三角洲泥岩发育区可能成为区域性盖层,为下一步大型油气藏的勘探提供重要的地质指导。
[Abstract]:In order to break through the early understanding of the sedimentary facies of the Neogene Guantao formation in the Liaodong Bay Depression, which restricts the further development of oil and gas exploration in this area, the analysis method of the combination of sedimentary geology, geophysics and paleontology is used. The geological background and evidence of lake and shallow water delta are analyzed in detail. Based on the sedimentary model of the lower member of Guantao formation and Minghuazhen formation in Liaohe Depression and the modern sedimentary comparison of Zhuonai Lake in Hoh Xili and Kusai Lake area, Combined with the results of paleo-humidity and paleo-temperature analysis revealed by the semi-quantitative analysis method of sporopollen percentage content and relative ratio, it is considered that the Guantao formation is dominated by alluvial fans and braided rivers under the climatic conditions of subtropical and increasing humidity. A shallow delta sedimentary model with the characteristics of the small front of the Great Plain. The delta plain can be divided into upper plain with alluvial fan and lower plain with braided river. The delta front has the characteristics of small scale, unstable plane, undeveloped estuarine dam and far sand dam. The closed lacustrine area of the lower member of Guantao formation is small, mainly of delta plain deposition, and the area of upper section of Guantao formation is enlarged, the delta front is more developed, and the secondary sag is connected by braided river system, which is characterized by open flow lake. The new understanding of the shallow water delta sedimentary system of the Neogene Guantao formation in the Liaodong Bay Depression makes the predelta mudstone development area possibly become the regional caprock, which provides important geological guidance for the next exploration of the large oil and gas reservoirs.
【作者单位】：成都理工大学沉积地质研究院;成都理工大学油气藏地质及开发工程国家重点实验室;中海石油(中国)有限公司天津分公司;
【基金】：国家自然科学基金青年基金项目(41602118)
【分类号】：P618.13

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