塔中Ⅲ区奥陶系良里塔格组沉积特征研究

发布时间：2018-09-02 09:42

【摘要】：论文以地层学、碳酸盐岩石学、沉积学等学科理论为指导,运用地质、地球物理等技术手段,在岩石学、沉积构造、生物等相标志识别的基础上,划分沉积微相类型,分析沉积微相纵向发育特征；通过沉积微相对比剖面分析沉积相横向展布特征；井震结合,划分地震相类型,并建立地震相对比剖面及平面分布图,分析地震相横向及平面分布特征；结合沉积相及地震相的研究成果,建立沉积相平面展布及分布模式,预测有利相带分布。 塔中Ⅲ区奥陶系良里塔格组划分为五个岩性段,细分为12个小层。大部分地区缺失良四段、良五段地层。整体上良里塔格组地层自南向北、自西向东有逐渐增厚的趋势。 研究区沉积相划分为开阔台地相和台地边缘相两个相带,开阔台地相可进一步划分为台内滩、灰泥丘和台内洼地、台内缓坡、滩间海亚相；台地边缘相可划分为台缘滩、灰泥丘、滩间海亚相。开阔台地中优势相为台内洼地、滩间海亚相,分别占沉积相总比的34%和28%,台内滩与灰泥丘发育较少,分别占17%和10%,台内缓坡占比13%。台地边缘相中台缘滩较发育,占沉积相总体的62%,其次发育灰泥丘沉积,所占比例为23%,滩间海亚相发育较少,仅为15%。阐述了沉积相在横向上的展布规律,开阔台地中台内滩、灰泥丘亚相的厚度较小、连续性差；滩间海与台内洼地亚相在开阔台地中发育规模大,横向上连续性好。台地边缘相中台缘滩发育规模较大,延展性强,滩体之间多以小规模的滩间海亚相相隔,灰泥丘较发育,具有一定连续性。 塔中Ⅲ区良里塔格组地震相可划分为丘状外形、弱-中强振幅相；丘状外形、强振幅、中等连续相等7种地震相类型。丘状反射和中弱振幅亚平行连续或断续反射对应于台地边缘相带中的高能台缘滩沉积,中-强振幅平行连续反射主要对应开阔台地内部的台内洼地和滩间海沉积。 平面上颗粒滩沉积主要发育在台地边缘相中,分布范围较广；在开阔台地内部颗粒滩数量减少,零星分布于大规模的台内洼地与滩间海之间。良里塔格沉积时期,海平面逐渐升高水体加深,高能滩体沉积逐渐减少,台地边缘相带变窄,低能滩间海、台内洼地亚相逐渐增多,开阔台地范围增加。其中良三段滩体较为发育,良二段为主要的灰泥丘发育层位,良一段滩体规模较小。 本次研究丰富了塔中地区的沉积研究,并可以为研究区下一步油气勘探提供了一定的地质指导。
[Abstract]:Guided by the theories of stratigraphy, carbonate petrology and sedimentology, the paper classifies sedimentary microfacies on the basis of the identification of lithology, sedimentary structure and biological facies by means of geology, geophysics and other technical means. The longitudinal developmental characteristics of sedimentary microfacies are analyzed, the lateral distribution characteristics of sedimentary facies are analyzed through sedimentary microfacies correlation profile, the seismic facies types are classified by well shock combination, and the seismic facies correlation profile and plane distribution map are established. The transverse and plane distribution characteristics of seismic facies are analyzed, and the distribution pattern of sedimentary facies is established to predict the distribution of favorable facies zone by combining the research results of sedimentary facies and seismic facies. The Lianglitag formation of Ordovician in Tazhong III area is divided into five lithologic sections and subdivided into 12 sublayers. The formation of the fourth formation and the formation of the fifth member of the formation are missing in most areas. As a whole, the strata of the Lianglitag formation are gradually thickening from south to north and from west to east. The sedimentary facies in the study area can be divided into two facies zones: open platform facies and platform margin facies. The open platform facies can be further divided into inner platform beach, plaster mound and platform depression, gentle slope within platform, subfacies between flats, platform margin facies can be divided into platform margin beach, Plaster mound, interbeach subfacies. The dominant facies in the open platform are the intra-platform depressions and the interbeach subfacies, which account for 34% and 28% of the total sedimentary facies, respectively. The development of the flat and the mound in the platform is less, accounting for 17% and 10%, respectively, and the gentle slope in the platform is 13% of the total sedimentary facies. In the platform margin facies, the platform margin beach is relatively developed, accounting for 62% of the total sedimentary facies, followed by the development of the mud mound deposit, accounting for 23%, and the sea subfacies between the beaches is less, only 15%. The regularity of distribution of sedimentary facies in the horizontal direction is expounded. The thickness of the inner beach in the open platform is small and the continuity is poor, and the subfacies between the beach and the subfacies of the depression within the platform has a large development scale in the open platform and good horizontal continuity. In the platform margin facies, the platform margin beach has a large scale and strong ductility, and the beach body is mostly separated by small scale interbeach subfacies, and the plaster mound is more developed and has a certain continuity. The seismic facies of Lianglitag formation in Tazhong 鈪，

本文编号：2218973