【作者】 翟振飞；

【导师】 傅恒；

【作者基本信息】 成都理工大学 ， 矿产普查与勘探， 2010， 硕士

【摘要】 本文作者在塔中地区构造背景的基础上以沉积岩石学、沉积学原理为指导,对塔中地区钻井的岩芯、薄片资料、测井资料以及地震资料进行分析,研究了塔中奥陶系的沉积相类型及其特征。在此基础上以Vail克拉通被动大陆边缘层序地层学基本原理和国际层序地层学发展的标准化趋势“层序界面根据需要灵活掌握、淡化模式、突出体系域”为指导,运用年代地层学、岩石地层学、生物地层学、地震地层学、同位素地层学等多科地层学原理,充分吸收前人有关研究成果,对岩芯、测井、地震资料进行了分析,确定了塔中奥陶系三级层序划分方案:划分为9个三级层序。通过井震相互约束连井对比和地震解释,分析了各层序在研究区的分布情况以及层序内的沉积相特征,建立了研究区奥陶系的层序地层格架并且根据各层序内沉积特点有重点选择了SQ3、SQ4、SQ5、SQ6按照三级层序而SQ7按照体系域进行了沉积相平面的制图。最后在层序和沉积相研究基础上,吸收前人对塔中奥陶系碳酸盐岩储层的控制因素研究成果,浅析了塔中奥陶系有利储集相带的分布情况。塔中卡塔克隆起在加里东期早期形成雏型,主要成型于加里东中期,海西早期基本定型。这两期构造运动对塔中奥陶系的沉积、层序和储层改造都具有重要影响。塔中地区岩性和锶同位素值变化趋势显示塔中奥陶纪海平面总体升高。岩芯、录井、测井资料和地震剖面显示,SQ1-SQ2主要发育局限碳酸盐岩台地相厚层灰质白云岩、白云质灰岩,与下伏寒武系芙蓉统呈整合接触。SQ3和SQ4主要发育局限-开阔台地相,仅在研究区东北、东南小范围存在台缘斜坡-陆棚相。研究区这四个层序以及其内的沉积相分布主要受海平面变化和古地貌的控制。SQ5沉积后,加里东中期Ⅰ幕构造运动使得SQ5大部分沉积地层遭到剥蚀,并且在构造高部位还见SQ3和SQ4地层剥蚀。其残留相主要为开阔台地和台地边缘以及斜坡盆地相,钻遇本层序的井主要分布在深水相区向塔中台地相区过渡地带如塘参1井、塔中88井、古隆1井、塔中29井、中41井、中2井、中4井等。此后海平面上升,在塔中低部位和台缘斜坡及其下至陆棚盆地区沉积了SQ6的紫红色、绿灰色泥晶灰岩、瘤状灰岩等,该层序仅在古隆1井、塔中88井、塘参1井、塔中29井钻遇。SQ7沉积期,塔中地区为孤立台地沉积背景,台地区广泛发育开阔台地和台地边缘相,包括有礁、丘、滩等有利碳酸盐岩储层发育相带;北部斜坡陡坡带以北地区以及南部缓坡以下如塘参1井为代表的塘古斯巴斯坳陷区主要是混积陆棚沉积。加里东中期Ⅱ幕运动对SQ7甚至以下层序产生了抬升剥蚀。此后塔中地区发生大规模海侵,塔中碳酸盐岩台地消亡,SQ8-SQ9主要为陆棚和盆地相沉积,尤其SQ7沉积期为非台地相的区域发育了一套规模巨大的浊积碎屑岩,如塘参1井、中41井、塔中29井、顺1井等井区这两个三级层序主要为浊积盆地相沉积。奥陶纪末发生的加里东中期Ⅲ幕运动以及志留纪末的加里东晚期以及泥盆纪末石炭纪初的海西早期运动也对塔中奥陶纪的地层改造和残留起了重要作用。塔中地区北部毗邻阿瓦提断陷和满加尔坳陷,南邻塔西南坳陷和塘古斯巴斯坳陷,寒武-石炭多套烃源岩都可以为塔中奥陶系碳酸盐岩储层输送油气,桑塔木组陆棚相或盆地相泥岩以及志留至石炭系也存在多套泥岩、粉砂质泥岩等潮坪至泻湖沉积,都可以做盖层,所以塔中地区储集体的分布基本上决定了有利勘探目标的分布。而塔中奥陶系储层多是SQ1-SQ7的碳酸盐岩储层,其非均质性很强,储层分布主要受沉积相带控制的原岩岩性和成岩作用以及构造破裂等因素的控制。作者在对塔中地区层序划分以及沉积相划分基础上,结合前人对塔中储层控制因素研究成果,叠合了各层序内以及多种控制因素控制的有储层分布范围,认为有利储集体主要分布在研究区中央断垒带潜山岩溶发裂缝育带、塔中南北坡折带高能沉积相岩溶裂缝发育带。更多还原

【Abstract】 The research area is Tazhong area which is in the center of the Tarim basin. Based on the tectonic setting of this area and guided by sedimentary petrology, sedimentary theory, the sedimentary facies and characteristics of which were studied and described with core,thin-section,well-log and seismic data.The restricted platform, the open platform, the margin of platform and the shelf or basin facies were identified and depicted.On that basis the author of this paper studied the features of the stratigraphy sequence in this region guided by the conception and theory of P.R.Vail’sseismicstratigraphysequence, chronostratigraphy,petrostratigraphy, Isotopic stratigraphy ,iostratigraphy and so on multidisciplinary stratigraphy and towards the standardization of sequence stratigraphy. Ten sequence boundaries and some important surfaces in the sequence and 9 sequences were recognized with the integration core, well-log and seismic data in the area.5 well tie profiles and 5 main seismic profiles, and a lot of cross line were selcted to interpret and depict the feature of each sequence,surely Well and seismic constrains each other.By studing the specific stratal stacking patterns and bounding surfaces, and consists of a tract of correlatable depositional systems and the interplay of accommodation and sedimentation , a sequence stratigraphic framework of the Ordovician in Tazhong area of Tarim basin was established.Sedimentary facies in each sequence were detailedly studied and according to the sedimentary characteristics of every sequence, SQ3, SQ4, SQ5, SQ6 was selected to map sedimentary phase plane in accordance with sequence, but SQ7 in accordance with systems tract.The Khattak uplift became rudiment uplift in the early Caledonian, mainly shaped in the medium-term period of Caledonian and formalized of early Hercynian. Those tectonic movements had significant impact on sedimentary, sequence and reservoir reconstruction of Ordovician by fractures and unconformity whicth caused. The interval-entropy map and strontium isotope ratios trends of the Ordovician in the area show that sea level of the Ordovician overall increased. Drill core, well logging, and seismic profiles shows SQ1-SQ2 mainly developed thick layer of restricted platform limy dolomite, dolomitic limestone deposition, was conformable contacted with underlying Furongian of Cambrian. SQ3 and SQ4 major developed constraints - open platform facies platform margin and slope - shelf sediments Only developed in north-east and south-east sub region of the study area. Occurred after deposition of SQ5 the mid-Ⅰscreen Caledonian tectonic movement eroded most of strata of SQ5, even denuded SQ3 and SQ4 in the structural high position. The residues are open platform ,platform margin and slope to basin facies, wells drilled in this sequence are mainly distributed in deep water areas in platform margin transition zone, such as Tangcan 1, Tz88 Gulong1, Tz 29 wells, Z41,Z2 wells. Then, the sea-level rise, low position in the area such as platform margin slope and the continental shelf to basin area deposited SQ6’gray and crimson knollenkalk deposits, the sequence only drilled by Gulong 1, Tz88 , Tangcan 1 Well, Tz29 well. When SQ7 deposited the area was isolated platform, widely developed open platform and platform margin, including reefs, reef flat, carbonate sands and other favorable carbonate reservoir facies which are parallel to the platform edge or locate in energetic area in open platform. In south and north of the area was shelf and basin facies such as Tangcan1 and Glong1,Tz34,Tz33,Shun1 well area.Then, the mid-Ⅱscreen movement of Caledonian eroded the strata of SQ7 differently even the underlying strata.And then Large-scale transgression happened, carbonate platform demised, SQ8 and SQ9 were mainly shelf and basin facies.some area saw turbidite basin facies such as Tz29,Gulong1,Tangcan1well and so on.Then the mid-Ⅲscreen movement of Caledonian and the early Hercynian movement changed those strata.The author hold that from the sequence SQ1 to SQ4 of Ordovician in the Tazhong area belonging to the stable aggradation’s sequences, are chiefly controlled by eustatic sea level change, while the sequence SQ5 to sequence SQ9 belonging to the tectonic drowning sequences are mainly controlled by regional tectonic movement because of generally eustatic sea level rise.At last, based on the previous study results about the controlling factors of Ordovician carbonate reservoir in the area and the characteristics of Sedimentary and sequence and Combined with the configuration among generating rock,reservoir and cap and with the generating conditions of oil-gas reservoir, that favorable reservoir are mainly distributed in burial hill with karsted well and fractured in the central study area and high-energy sedimentary facies in south and north Slope zone with well karst and fracture.更多还原