成都凹陷沙溪庙组沉积特征研究

发布时间：2018-05-22 13:32

本文选题：成都凹陷 + 沙溪庙组　；参考：《长江大学》2015年硕士论文

【摘要】：成都凹陷位于四川盆地西部,龙门山系中南段与龙泉山、总岗山之间的平原地区,面积约为5000km2；凹陷以北为北东东向隆起的新场构造带,以西为北东-南西向展布的大邑-安县构造带(龙门山前构造带),以东为南北向展布的知新场构造带；行政区属于成都市、崇州市、彭州市、都江堰市、德阳市、广汉市和什邡市。研究区属于构造弱变形区,目前研究区的沙溪庙组主要勘探开发的区块有区域东北部的彭县-德阳大型向斜区,北部的孝-新-合构造带区域,以及南部的新都-成都斜坡平缓构造带区域。成都凹陷经历了印支、燕山、喜山等多期构造运动,在晚三叠世,温江、马井地区开始形成构造雏形,而新都-洛带地区的构造还未形成；早侏罗世,温江、马井、新都-洛带地区的构造都开始逐步形成,德阳-广汉一带的向斜也随着正向构造的形成,相切的幅度也不断增大；晚侏罗世,温江构造体现出隆起的继承性,闭合面积和幅度都在逐渐减小；一直到早白垩世末,沙溪庙组地层才持续隆起,新都-洛带地区随着构造运动的挤压,以及龙泉山断裂的发展,形成背斜；在喜山运动的影响下,马井背斜南东方向伴生的马井断裂发育,活动贯穿了马井背斜形成的整个时期；在喜山运动晚期,新都-洛带地区的背斜在构造运动的挤压下,形成了现今的新都鼻状构造以及洛带的背斜构造。下沙溪庙组与下伏千佛崖组在剖面上表现为下沙溪庙组底部的“关口砂岩”对不整合界面的渐进超覆不整合接触；上、下沙溪庙组之间以“叶肢介页岩”作为识别界面的标志,但不是所有不整合界面上都有该标志；遂宁组与上沙溪庙组之间在盆地内部表现为相关整合面,垂向上表现为由粗转细的相转换界面。将沙溪庙组划分为3个段：分别是下沙溪庙组、上沙溪庙组下段和上沙溪庙组下段。并可进一步将沙溪庙组划分为J2S33、J2S32、J2S34、J2S24、J2S23、J2S22、J2S24、J2S44、 J2S43、J2S42、J2S44,一共11个砂组。通过砂岩岩屑类型分布分析、重矿物组合(ZTR指数)特征分析、轻碎屑组分分析等,结合成都凹陷周围古地貌的特征,确定成都凹陷主要物源方向有两个：一是盆地北缘的米仓山-大巴山,二是西北缘的龙门山。其中成都凹陷西部的崇州-郫县-彭州地区主要收到西部龙门山物源的影响；东部的德阳-金堂-洛带地区主要受到东北部米仓山-大巴山物源的影响；中部马井、新繁地区显示明显多物源的特征,除了受到东北、北部远物源影响外,还受到西北部龙门山近物源的影响。前人对成都凹陷侏罗系沙溪庙组沉积相进行过-些研究,本文通过岩心观察、描述,以及测录井资料、分析化验资料等的分析,认为成都凹陷侏罗系沙溪庙组主要存在两大沉积体系：近源的辫状河三角洲沉积体系(短轴)以及远源的曲流河三角洲沉积体系(长轴)。凹陷西部以龙门山中段物源为主,主要为北西-南东向短轴辫状河三角洲沉积,砂体呈片状分布；凹陷中部、东部以龙门山北段、米仓山物源为主,主要为北东-南西向长轴曲流河三角洲沉积,河道砂体发育,砂体主要呈条带状分布。三角洲平原、三角洲前缘及前三角洲亚相均有发育,沉积微相包括分流河道、水下分流河道、分流间湾、河口坝、远砂坝微相等。在研究区内,辫状河三角洲沉积与曲流河三角洲沉积的不同体现在：一是沉积物平均粒度大小上,辫状河三角洲与与之对应的曲流河三角洲沉积微相的沉积粒度相比较大；二是辫状河三角洲沉积体系中不发育或者发育较少的远砂坝微相。本文通过选取研究区内由不用物源主导的单井,对比了两种三角洲沉积之间的差异。研究区重点砂组在下沙溪庙组有J2S33、J2S31,上沙溪庙组下段全部砂组均为重点砂组,上沙溪庙组上段有J2S14、J2S14。各砂组的砂体分布特征均有不同,本次就不同重点砂组砂体分布特征的不同进行了描述,为勘探开发的下一步工作打好了基础。沙溪庙组形成时期总体显示为湖平面不断上升的过程,虽其内部也出现多次小幅度湖平面上升、下降的反复。在下沙溪庙组沉积时期,成都凹陷砂体发育,砂体厚度较大,主要为三角洲前缘亚相沉积；在上沙溪庙组下亚段沉积时期,与下沙溪庙组不同,成都凹陷内马井-什邡、崇州-郫县地区为三角洲前缘-平原亚相沉积,广汉-金堂、新都-洛带地区为三角洲前缘亚相沉积；在上沙溪庙组上亚段沉积时期,基本延续上沙溪庙组下亚段沉积格局,三角洲前缘面积有所减小。沉积过程的动态演化显示不同沉积体系在不同时期的展布范围具有继承性,却又存在一定的差异。剖面显示,沙溪庙组沉积期间,湖盆水体的升降较为频繁,并且整个沙溪庙组在纵向上各砂组的砂体发育程度是不同的,主要取决于其所处的基准面旋回的部位。本区的砂体主要集中发育在中期旋回的上升基准面早期,其次是下降基准面晚期,不同时期形成的砂体相互叠置拼接,使得研究区砂体在垂向上总体厚度较大,并且在平面分布上连续性较好,是油气聚集及储存的有利部位。
[Abstract]:The Chengdu sag is located in the west of the Sichuan basin, the plain area between the middle and southern section of the Longmen mountain system and the Longquan mountain and the general Gang mountain, with an area of about 5000km2, the North East to the East and the new field tectonic belt in the north of the sag, the Dayi an County tectonic belt (the front of the Longmen mountain tectonic belt) to the West and the east to the north and the north. The district belongs to Chengdu, Chongzhou, Pengzhou, Dujiangyan, Deyang, Guanghan and Shifang. The research area belongs to the structural weak deformation zone. The main exploration and development area of the Shaxi Temple group in the study area is the Peng County Deyang large Syncline area in the northeast of the region, the northern part of the filial and new combined tectonic zone, and the Southern new capital. The Chengdu sag has experienced many tectonic movements, such as Indo, Yanshan, Himalayan and other tectonic movements. In the late three fold, Wenjiang and Ma well began to form a structural prototype, while the structure of the new Du Luodai region had not been formed; the structures of the early Jurassic, Wenjiang, Ma well and the Xindu Luodai region began to form gradually, and the Deyang - Guanghan area was gradually formed. The syncline is also formed with the formation of the positive structure, and the amplitude of the tangent is also increasing; the late Jurassic, the Wenjiang structure embodies the inheritance of the uplift, and the closed area and amplitude are gradually decreasing; from the end of the early Cretaceous to the end of the early Cretaceous, the Shaxi Temple formation continues to rise, the new Du Luodai region is extruded with the tectonic movement and the Longquan mountain fracture. Under the influence of the Himalayan movement, the well developed in the south east direction of the Ma well anticline is developed, and the activity runs through the whole period of the formation of the horse well anticline. In the late Xi Shan movement, the anticline in the Xindu Luodai area was squeezed by the tectonic movement, forming the present new metropolitan structure and the Luodai anticline structure. The Xi Miao formation and the lower Qian Buddha cliff formation show the progressive overlying unconformity contact of the "Guan Kou sandstone" on the unconformable interface at the bottom of the lower Shaxi Temple formation, and the "leaf limb mesoporous shale" between the Xiashi Temple group as a symbol of the recognition interface, but not all the unconformities on the interface, and the Suining group and the upper Shaxi Temple group. The Shaxi Temple group is divided into 3 sections: Xiashan Temple group, upper Shaxi Temple formation lower section and upper Shaxi Temple group lower section, respectively. The Shaxi Temple group can be further divided into J2S33, J2S32, J2S34, J2S24, J2S23, J2S22, J2S24, J2S44, J2S43, J2S42. J2S44, a total of 11 sand groups. Through the analysis of the type distribution of sandstone debris, the analysis of the combination of heavy minerals (ZTR index), the analysis of the light detrital component, and the characteristics of the paleogomorphology around the Chengdu depression, there are two main source directions of the Chengdu sag: one is the rice Cangshan Daba Mountain in the northern margin of the basin, and the two of the Longmen mountain in the northwest margin. Chengdu is the Longmen mountain in the northwest margin. The Chongzhou Pixian Pengzhou region in the west of the depression is mainly affected by the source of the western Longmen mountain, and the Deyang Jintang Luodai area in the East is mainly influenced by the source of the north northeast m Cangshan Daba Mountain. The central well and the new propagation area show the characteristics of the obvious multiple source. Besides the influence of the East North and the northern far source, the northwest part is also subject to the northwest. The influence of the near source of the Longmen mountain. The predecessors have studied the sedimentary facies of the Jurassic Shaxi Temple formation in the Chengdu depression. Through the analysis of the core observation, description, logging data and analysis of the laboratory data, it is believed that there are two major sedimentation systems in the Shaxi Temple formation of the Jurassic in the Chengdu depression: the braid delta depositional system of the near source (short) In the west of the depression, the main source is the source of the middle Longmen mountain, mainly from the North West to the short axis Braided River Delta, and the sand body is flaky, in the middle of the depression, in the eastern part of the Longmen mountain, the main source of the rice in the rice of the North East and the South West to the long axis of the River Delta. The channel sand body is developed and the sand body is mainly banded distribution. Delta plain, delta front and anterior delta subfacies are developed, sedimentary microfacies include distributary channel, underwater distributary channel, distributary Bay, estuarine dam, and far sand dam. In the average grain size of the sediments, the braided river delta is larger than the sedimentary granularity of the sedimentary microfacies of the corresponding Meandering River Delta, and the two is the micro facies of the long sand dams that are not developed or developed in the braided river delta depositional system. In this paper, two kinds of triangles are compared by selecting a single well dominated by unused source in the study area. The main sand groups in the Xiasha Temple formation in Xiasha Temple group are J2S33, J2S31, and upper Shaxi Temple formation in the lower Shaxi Temple formation, the key sand groups in the lower Sha Xi Temple formation are the key sand groups, and the upper part of the upper Shaxi Temple Group has J2S14, and the sand body distribution characteristics of the J2S14. sand groups are different, this time the different sand body distribution characteristics of different key sand groups were described, for exploration and development. In the formation period of the Shaxi Temple formation, the formation period of the Temple group was generally shown as the rising process of the lake level. Although there were several small amplitude lake levels rising and decreasing, the sand body of the Chengdu sag developed and the sand body was thick, mainly the delta front subfacies, and the upper Shaxi temple in the Xiashan Temple formation. The lower subsection sedimentary period is different from the lower Shaxi Temple group. The Chengdu sag Nei Ma Jing - Shifang, Chongzhou - Pixian area is delta front plain subfacies deposit, Guanghan Jintang and Xindu Luodai area is delta front subfacies deposit. In the upper subsection of upper Shaxi Temple formation, the lower subsection of Shaxi Temple subsection was basically extended. The area of the front edge of the continent decreases. The dynamic evolution of the deposition process shows that the distribution range of the different depositional systems is inheriting, but there is a certain difference. The section shows that during the period of the Shaxi Temple formation, the water body of the lake basin is more frequent, and the development degree of the sand body in the longitudinal sand groups in the whole Shaxi Temple group is not. The same is mainly determined by the position of the base level cycle. The sand bodies in this area are mainly concentrated in the early stage of the rising datum of the mid-term cycle, followed by the late descent datum, and the sand bodies formed in different periods are stacked and spliced each other, making the sand body in the vertical upper body thick and continuous in the plane distribution. Well, it is a favorable place for oil and gas accumulation and storage.
【学位授予单位】：长江大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P618.13

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