川东北元坝地区中侏罗统千佛崖组沉积相研究

发布时间：2018-02-28 09:34

本文关键词： 中侏罗统千佛崖组地层对比沉积相沉积模式　出处：《成都理工大学》2016年硕士论文　论文类型：学位论文

【摘要】：川东北元坝地区是四川盆地内有利的油气储备区块,勘探结果显示该地区中侏罗统千佛崖组具有较好的油气勘探潜力,但由于前期对千佛崖组沉积特征、沉积模式和沉积演化规律等研究不够深入,制约了该地区千佛崖组的油气勘探工作。基于此,本文以沉积学理论为指导,以旺苍金溪镇剖面、广元荣山镇剖面、南江桥亭剖面和渠县三汇剖面为骨干剖面,结合钻井岩心观察,在大量岩石薄片观察和各类测试分析的基础上,对川东北元坝地区中侏罗统千佛崖组地层特征和沉积特征进行了深入研究,建立了千佛崖组的沉积模式,明确了元坝地区千佛崖组沉积相展布特征和沉积演化规律,为进一步勘明中侏罗统千佛崖组的油气储藏情况奠定了基础在对3条实测剖面、7条观测剖面和20余口重点井取芯段观察分析的基础上,总结出元坝地区千佛崖组具有“上杂、下杂、中间深”的特点,据此将千佛崖组划分为三个亚段。其中,千佛崖组一段以杂色泥岩与灰色细粉砂岩互层为主,间夹薄层紫红色泥岩,测井曲线多见锯齿形;千佛崖组二段;千佛崖组测井曲线呈箱形。千佛崖组三段的厚度是千佛崖组中最大的,岩性主要为杂色泥岩,灰绿色细-粉砂岩和泥质粉砂岩与灰黑色页岩互层发育,无集中成层的黑色页岩,测井曲线呈齿形和漏斗形。在对元坝地区千佛崖组岩性、电性、古生物和各类地球化学等相标志研究和识别的基础上,认为千佛崖组沉积环境为三角洲和湖泊沉积相,发育三角洲平原、三角洲前缘、前三角洲和滨浅湖沉积四类亚相,水下分流河道、水下分流间湾、水下天然堤、河口坝、远砂坝、席状砂、浅湖泥和浅湖砂坝等微相。元坝地区千佛崖组沉积环境总体为三角洲-湖泊沉积模式。研究区在千佛崖组时期主要受燕山运动影响,盆地性质为米仓山—大巴山类前陆盆地。物源补给主要来源于龙门山和米仓山-大巴山地区。从物源区携带的泥砂碎屑物质快速堆积形成三角洲沉积带,随着构造沉降,逐渐过渡为湖泊相。从千一段到千三段主要发育三角洲相和湖泊相沉积环境。其中三角洲相主要以三角洲前缘亚相为主,湖泊相以浅湖亚相为主。中侏罗世千佛崖期元坝地区发育三角洲-湖泊沉积,平面上以三角洲前缘亚相和浅湖亚相为优势相。千一段沉积期,主河道发育在中部和西部,此时三角洲向湖推进至研究区南部边缘;千二段沉积期,中部和西部物源持续供给,主河道稳定发育,东部地区三角洲沉积已开始收缩;千三段沉积期,西部和中部河道稳定并向湖推进,东部地区三角洲向东北方向萎缩。
[Abstract]:The Yuanba area in northeast Sichuan is a favorable oil and gas reserve block in Sichuan basin. The exploration results show that Qianfoya formation of the Middle Jurassic in this area has good oil and gas exploration potential, but due to the sedimentary characteristics of Qianfoya formation in the early stage, The research on sedimentary model and sedimentary evolution is not deep enough, which restricts the oil and gas exploration work of Qianfoya formation in this area. Based on this, this paper, guided by sedimentology theory, takes WangCang Jinxi section and Guangyuan Rongshan section as guidance. Nanjiangqiao Ting section and Quxian Sanhui section are the backbone sections, combined with drilling core observation, on the basis of a large number of thin pieces of rock observation and various kinds of test and analysis. The stratigraphic and sedimentary characteristics of the Qianfoya formation of the Middle Jurassic in the Yuanba area of northeast Sichuan are studied, the sedimentary model of the Qianfoya formation is established, and the distribution characteristics of sedimentary facies and the regularity of sedimentary evolution of the Qianfeiya formation in the Yuanba area are clarified. For the further exploration of the oil and gas reservoir of Qianfoya formation of the Middle Jurassic in the Ming Dynasty, on the basis of observation and analysis of 3 observed sections and 7 observation sections and more than 20 key wells, it is concluded that the Qianfeiya formation in Yuanba area has "upper complex". The Qianfoya formation is divided into three subsections according to the characteristics of the lower complex and the middle depth. The first section of the Qianfoya formation is mainly composed of mixed mudstone and gray fine siltstone interbedded with thin layer purple mudstone between which the logging curves are mostly sawtooth. The logging curve of Qianfoya formation is box-shaped. The thickness of the third member of Qianfoya formation is the largest in Qianfoya formation, and its lithology is mainly mixed mudstone, gray-green fine siltstone and mudstone interbedded with gray and black shale. The logging curves are toothed and funnel-shaped. Based on the study and identification of lithology, electrical properties, paleontology and geochemistry of Qianfoya formation in Yuanba area, It is considered that the sedimentary environment of Qianfoya formation is delta and lacustrine facies, delta plain, delta front, prodelta and littoral shallow lake sedimentary subfacies, underwater distributary channel, underwater distributary bay, underwater natural embankment, estuary dam, etc. The sedimentary environment of Qianfeiya formation in Yuanba area is a deltaic lake sedimentary model. The study area was mainly influenced by Yanshanian movement during the Qianfoya formation period. The nature of the basin is the Mickangshan-Daba Foreland basin. The material supply mainly comes from the Longmen Mountain and the Mecang Mountain Dabashan area. The mud sand clastic material from the source area rapidly accumulates to form a delta sedimentary belt, and along with the tectonic subsidence, the silt detrital material from the source area forms a delta sedimentary zone. The delta facies and lacustrine facies sedimentary environment are mainly developed from Qianyi to Thousand three members. The delta facies mainly consists of delta front subfacies. The lacustrine facies is dominated by shallow lacustrine subfacies. The delta lacustrine deposits were developed in Yuanba area of Qianfoya period in the Middle Jurassic, and the delta front subfacies and shallow lake subfacies were the dominant facies on the plane. At this time, the delta advances to the southern edge of the study area, the sedimentary period of the Qian2 formation, the supply of provenance in the central and western regions, the steady development of the main river channel, the beginning of contraction of the delta sediments in the eastern region, the sedimentary period of the thousand three member, The western and central rivers are stable and advancing toward the lake, while the eastern delta shrinks to the northeast.
【学位授予单位】：成都理工大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：P618.13

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