【作者】 周大志；

【导师】 李国蓉；

【作者基本信息】 成都理工大学 ， 矿产普查与勘探， 2010， 硕士

【摘要】 本论文以四川盆地东南地区志留系石牛栏组碳酸盐岩为研究对象,依据碳酸盐岩层序地层学、储层沉积学、储层地质学等多学科的理论,运用野外和室内、宏观与微观相结合的方法,重点开展对川东南志留系石牛栏组的层序地层、沉积相、成岩作用、储层特征等方面的研究,查明了石牛栏组层序地层特征、沉积相展布特征,明确了石牛栏组碳酸盐岩成岩作用及其对储层的影响、储层特征。首先,通过识别每一条剖面和每一口钻井的关键层序界面,进行层序划分;在多条剖面和多口钻井层序地层研究的基础上,分析了层序及体系域的特征,建立了层序地层格架,实现了跨越台地-陆棚区的三级层序、体系域的对比。将石牛栏组划分为4个三级层序,每个三级层序都包括海侵体系域和高水位体系域。其次,利用钻井岩心、野外露头、岩石薄片等资料,通过石牛栏组典型剖面沉积相柱状剖面图的建立,对目的层进行了沉积相研究,并建立了沉积模式,确定了石牛栏组沉积相类型、特征,并以体系域为制图单元,绘制了石牛栏组各时期的沉积相展布。该区石牛栏组主要的沉积相类型有局限台地相、开阔台地相、台地边缘浅滩相、台地边缘斜坡相和陆棚相五个相带。并对石牛栏组滩体的展布及发育规律进行了分析。石牛栏组滩体发育于2个部位,即台地边缘及台内零散分布的生屑滩。石牛栏组时期的碳酸盐岩台地边缘滩主要发育于中上部三级层序的高水位体系域中,由于海平面升降及碳酸盐产率的控制作用,滩体经过了从进积型到退积型的过程。再次,在沉积相研究的基础上,利用岩石学、地球化学等方法,结合大量薄片资料,详细阐述了主要成岩作用的表现形式及特征,分析了其对储层的影响,对成岩序列、成岩阶段进行了划分。并得出结论:石牛栏组储层在其埋藏过程中经历了相对简单的成岩演化过程,强烈的压实作用和胶结作用破坏了几乎所有的原生孔隙和部分次生孔隙,使研究区内碳酸盐岩成为致密型储层。经过了同生期、早成岩期、晚成岩期及构造期四个成岩阶段的演化,使得石牛栏组储层的储集能力大大降低。最后,通过薄片、孔渗、压汞等分析手段及资料,研究石牛栏组储层发育的主要层段、储集空间类型、物性、孔隙结构等特征,确定储层类型。石牛栏组岩石类型多样,主要有泥(质)灰岩类、瘤状灰岩类、微晶(泥)灰岩类、颗粒灰岩类、藻粘结灰岩类、白云岩类等。石牛栏组碳酸盐岩储层的储渗空间类型主要为裂缝、沿裂缝溶蚀孔洞、粒间溶孔,且现今多为沥青赋存。石牛栏组储层物性总体较差,平均孔隙度只有1.58%,有近73%的样品孔隙度小于2%,超过50%的样品渗透率小于0.2个毫达西。早期形成的大的孔隙绝大多数己经被有机质、方解石等充填,现今只有一些微孔隙,因此,石牛栏组的物性是相当差的,只有部分裂缝型储层发育。更多还原

【Abstract】 This thesis focuses on the Shiniulan formation carbonate reservoir in the Southeast Area of Sichuan Basin, under the guidance of the Carbonate Sequence Stratigraphy, Reservoir Sedimentology, Reservoir Geology, and by means of the combined methods of indoor & outdoor and macroscopy & microscopy, stratigraphic sequence, sedimentary facies, diagenesis and reservoir characteristics of Shiniulan Formation are studied emphatically. As a result, the characteristics of stratigraphic sequence and sedimentary facies in Shiniulan Formation are found out, and the main diagenesis, its effect on reservoir and reservoir characteristics are made clear.Firstly, identification on key sequence boundaries of each outcrop and drilling core is presented at first, to classify sequence stratigraphy; then, on the basis of sequence stratigraphic classification of all outcrops and drilling cores, the characteristics of sequences and tracts are analyzed; at last, the Shiniulan Formation sequence stratigraphic framework is established, so contrast of sequences and tracts cross platform-shelf is also achieved. The Shiniulan Formation in the Southeast area of Sichuan Basin is divided into four 3rd-order sequences, each sequence includes transgressive systems tract and high systems tract.Secondly, based on the data of drilling cores, outcrops and microsection, and by establishing the sedimentary facies columnar section of typical sections, sedimentary facies of the objective interval are analyzed; depositional model is also established; then, sedimentary facies types and characteristics are confirmed; at last, using tract as basic unit, the distribution of different sedimentary facies throughout different periods is mapped. The main sedimentary facies types include restricted platform facies, open platform facies, shoal facies of platform margin, platform ramp facies and continental shelf facies. The distribution and development rule of Shiniulan shoal patch is analyzed. The Shiniulan shoal patch develops in two places, the platform margin and the internal platform. The platform margin shoal develops in the high system tract of the upper 3rd-order sequences, and it transforms from progradation to retrogradation due to the eustatic sea level change and carbonate production rate.Thirdly, on the basis of sedimentary facies, combining the methods of petrology and geochemistry with a large number of microsection data, both pattern and characteristics of the main diagenesis are illustrated in detail and their effect on reservoir is analyzed; and then, both diagenetic sequence and stages are also classified. The conclusions as follow: The Shiniulan reservoir experiences relatively simple diagenetic evolution in its burial history,intense compaction and cementation have destructed almost all primary pores and part secondary pores. As a result, Shiniulan carbonate rock in the studied area becomes a kind of tight reservoir. The reservoir capacity in Shiniulan Formation decreases a lot after four diagenetic stages including syndiagenetic stage, eogenetic stage, postdiagenetic stage and tectonic stage.Lastly, based on the data of microsection, porosity, permeability and mercury penetration, the reservoir interval,reservoir spaces,physical property and pore configuration are analyzed; then, the types of reservoir are also verified. The lithological types of reservoir in Shiniulan formation are diverse, including marlite, knollenkalk, microcrystalline limestone, grain micrite and dolomite. The main reservoir spaces of Shiniulan carbonate rock are cracks, corrosion pores along the cracks and intergranular dissolution pores, but they are all filled by bitumen now. Generally, the Shiniulan reservoir is characterized to be tight with low matrix porosity, the average is 1.58%, and about 73% of which belows 1%; above 50% of the sample permeability belows 0.2 millidarcy. The large pores generated previously are mostly filled by organic matter and calcite, left some micropore only. So the physical property of Shiniulan carbonate is very poor, and it only develops some fractured reservoir.更多还原