准噶尔盆地春光区块沙湾组地震沉积学分析及砂体结构研究

发布时间：2018-06-30 18:53

本文选题：准噶尔盆地 + 沙湾组　；参考：《中国地质大学》2017年博士论文

【摘要】：准噶尔盆地车排子凸起春光区块新近系沙湾组具有多物源、多沉积体系特点。由于不同时期岩心、测井、测试分析和地震资料参差不齐,沉积体系认识争议较大,早期研究认为研究区以水下沉积为主,发育缓坡扇三角洲-辫状河三角洲-湖泊沉积体系;近期研究认为研究区为陆上暴露沉积,发育冲积扇-河流沉积体系。沉积规律认识的不足,致使钻井频频失利,严重阻碍了研究区岩性油气藏勘探开发的进程,迫切需要新的方法来精细刻画其沉积体系及砂体特征。论文基于岩心、测井、地震和测试分析等资料,在层序地层学、应用沉积学、储层地质学、测井地质学、地震沉积学等理论的指导下,首先在露头、测井及地震资料结合的基础上建立了等时层序地层单元格架;利用地震沉积学技术对研究区典型沉积特征进行分析;通过详细的岩心沉积学分析划分了岩石相类型和沉积微相类型,分析了沉积微相展布、沉积模式及沉积演化特征;在砂体成因类型划分的基础上,对砂体平面展布规律、几何形态、接触样式及叠置模式进行总结分析;最后基于Google Earth对现代沉积的定量分析,综合利用地层切片及测井资料,对研究区砂体进行定量表征,并对有利储集砂体分布特征进行阐述,对有利目标区进行预测。论文得出的主要认识和结论如下:物源体系分析方面,在古地貌分析的基础上,结合锆石定年、重矿物、古水流和砂地比综合判断。(1)锆石定年结果表明研究区碎屑锆石年龄峰值(400 Ma)与东北部的阿尔泰山(峰值505 Ma)相差较远,与南部天山(峰值313 Ma)不符,与西北部扎伊尔山(峰值391 Ma)相吻合,表明西北部扎伊尔山是研究区的主要物源区;(2)研究区发育两大碎屑物源方向:西北-北部方向和东北方向;沙湾组沉积早期物源方向为西北和东北方向,以东北方向为主;到沙湾组晚期,物源方向有所偏移,以北部为主。等时层序地层格架方面,在Vail经典层序地层学理论指导下,结合露头、测井及地震响应特征,建立了春光区块新近系沙湾组高精度等时地层格架,将其划分为2个三级层序(NSQ1、NSQ2),4个四级层序。沙湾组顶底界面均为区域不整合面,地层由东南向西北超覆。沙湾组沉积时期研究区地形较缓,且位于构造相对较高部位,低位体系域不发育,以湖侵体系域与高位体系域为主。NSQ1层序,对应于沙湾组沙一段(N1s1),层序构型以湖侵体系域(TST)为主,高位体系域(HST)为辅。岩性较粗,沉积多期厚层砂砾岩,泥质含量低;NSQ2层序,对应于沙湾组沙二段(N1s2)及沙三段(N1s3),层序构型特征以高位体系域(HST)为主,湖侵体系域(TST)为辅,岩性较细,以含砾细砂岩、细砂岩为主,砂体厚度小。地震沉积学分析方面,通过90°相位转换建立地震同相轴与岩性对应关系;通过岩石物理关系分析得到砂泥岩识别特征;自下而上筛选典型地层切片进行分析,地层切片见不规则椭圆形(菱形)和哑铃形强负振幅异常体、多期高弯曲河道状振幅异常体环绕不规则弓形强振幅异常体分布以及大量细窄振幅异常体条带群,标定为心滩、边滩及三角洲分流河道沉积,丰富了沉积体系的认识。岩石学特征方面,研究区整体岩屑含量高,石英含量相对较低,为低成熟特征,且不同井区其含量具有一定的差异。研究区西北部以岩屑砂岩为主,镜下见棱角状-次棱角状矿物点-线接触,颗粒大小混杂,分选较差,为近物源低成熟特征;研究区东北部以岩屑长石砂岩和长石岩屑砂岩为主,镜下见棱角状-次棱角状矿物杂基支撑,分选一般,成熟度较低;研究区中部以岩屑长石砂岩和岩屑砂岩为主,镜下见棱角状-次棱角状矿物杂基支撑,为低成熟的特点;研究区西南部以岩屑长石砂岩为主,石英含量相对较高,为较高成熟的特点,镜下见棱角状-次棱角状矿物杂基支撑,分选一般。通过详细的岩心沉积学分析,将研究区沙湾组划分为7种岩石相类型:杂色块状砾岩岩石相、含砾砂岩岩石相、中粗砂岩岩石相、粉细砂岩岩石相、含砾泥岩岩石相、泥岩岩石相和石膏岩石相。5种测井相:箱形、钟形、漏斗形、指形和平直形。整体上为平行-亚平行、中强振幅、中高频率、中好连续性地震相。结合岩石相、测井相、地震相、单井相及地层切片响应特征,认为研究区发育冲积扇、辫状河、曲流河、浅水三角洲、扇三角洲及滨浅湖6种沉积体系类型及24种沉积微相类型,其中冲积扇以扇端亚相为主,发育辫状河道、泥石流和片流沉积微相;辫状河分为河床亚相、堤岸亚相及河漫亚相,进一步细分为河床滞留沉积、河道充填、心滩、天然堤及泛滥平原沉积微相;曲流河分为河床亚相、堤岸亚相、河漫亚相以及牛轭湖亚相,包括河床滞留沉积、河道充填、边滩、天然堤、泛滥平原、废弃河道等沉积微相;浅水三角洲沉积体系进一步分为三角洲平原和三角洲前缘亚相,三角洲平原亚相可划分为分流河道、分支间湾、废弃河道及天然堤等沉积微相,三角洲前缘可进一步划分为水下分流河道、席状砂、分支间湾及废弃河道等沉积微相;扇三角洲以前缘亚相为主,细分为水下分流河道、河道间和席状砂等沉积微相。并对不同沉积微相类型的岩性、砂体厚度、测井相形态及地震响应特征进行了分析。沉积微相展布、沉积模式方面,不同物源区砂体厚度差异较大,且砂体之间不连通,中间为泥岩发育带。纵向上砂体发育不均匀,向上砂厚减薄且连通性降低;沉积微相分布复杂,沙一段以辫状河为主,呈北东-南西向展布,西北部发育小规模冲积扇;沙二段沉积早期,辫状河向曲流河转变,边滩复合体发育,在南部末端,开始出现浅水三角洲平原沉积,冲积扇仍局部发育。随着湖水的持续上升及物源方向的迁移,沙二段晚期,北部发育扇三角洲,南部发育滨浅湖及浅水三角洲前缘,沙三段沉积时期,湖平面下降,北部发育冲积扇,南部广泛发育泛滥平原沉积。并建立冲积扇-辫状河沉积模式及扇三角洲-浅水三角洲沉积模式。单砂体按照成因细分为心滩、边滩、分流河道、水下分流河道及席状砂等,不同类型砂体在发育部位、砂体特征、测井特征及地震反射形态上均有不同响应。心滩砂体位于研究区沙湾组底部沙一段,具有顺流平缓前积、垂向多期增生体加积的特点,砂体相互切割叠置,常呈泛连通体分布。岩性以砂砾岩为主,砂体厚度大,平均在20m左右,为多期砂体叠置沉积而成,测井曲线以厚层高幅齿化箱形为主。砂体底部见河床滞留沉积,顶部发育落淤层。地震反射表现为强振幅低连续,地层切片上多呈不规则椭圆形、菱形或哑铃形。边滩砂体发育在沙二段,是河流侧向迁移和沉积物侧向加积的结果。岩性以灰色含砾细砂岩为主,分选磨圆中等,泥质含量较高,单期河道砂体厚度在3 m~15 m,测井曲线为中高幅齿化箱形和宽指形。地震反射表现为强振幅-中好连续。地层切片为不规则弓形强振幅异常体。分流河道砂体是浅水三角洲平原最主要的砂体类型。岩性较细,以中细砂岩、含砾细砂岩为主,分选磨圆均较好,泥质含量高,局部见冲刷面。单砂体厚度中等,在3 m~10 m左右。测井曲线以宽指形和齿化箱形为主。地震反射表现为强振幅-中好连续,见透镜状,地层切片上为细窄条带状,呈北东-南西向展布。水下分流河道是浅水三角洲前缘骨架砂体,岩性较细,以中细砂岩为主,砂体厚度在5m左右,测井曲线以宽指形为主,为中-强振幅、中好连续性、亚平行地震相,地层切片上见细小强振幅呈近东西向条带状展布。席状砂是沉积物在湖水作用下发生横向迁移而成。整体上粒度较细,以细砂岩、粉砂岩为主,砂体厚度较薄,在3 m左右,测井曲线为指形。地震反射为亚平行-中振幅-中好连续性,地层切片上多呈面状展布。砂体结构方面,通过对砂体解剖分析,认为研究区砂体几何平面形态主要有4类:条带状、树枝状、透镜状(豆荚状)及席状;砂体平面接触样式主要有4种类型:侧向切叠式、间湾相隔式、水平搭接式及孤立式;砂体叠置样式可划分为3大类5小类:堆叠式、侧叠式及孤立式。其中,堆叠式包括垂向叠加式和垂向切叠式;侧叠式可分为侧向叠加式和侧向切叠式。随湖平面上升及可容纳空间/沉积物补给通量值(A/S)增大,砂体结构由堆叠式向侧叠式过渡,并逐渐向孤立式演变。砂体定量表征方面,本次研究基于卫星照片、测井、地震资料,以现代沉积为出发点,对研究区主要砂体进行定量表征。通过对玛曲辫状河河道宽度、心滩长度及宽度、曲流河河道宽度与边滩长度的测量,进行拟合分析,建立定量模型,并利用地层切片分辨率高的优点,进行验证分析,表明模型具有较好的适用性。此外,浅水三角洲分流河道在地层切片上响应特征清晰,通过在地层切片上标定河道宽度,并统计与之对应的河道砂体厚度,从而建立起河道宽度与砂体厚度的定量模型,复相关系数达0.82,为稀井网区砂体定量预测奠定基础。在对研究区主要单砂体成因、有利砂体分布特征详细分析的基础上,结合对砂体尖灭带的认识、砂体的定量研究、油气成藏特点及地震响应特征,筛选了三个有利目标区。
[Abstract]:The Neogene Shawan Formation of the spring light block in the Junggar basin is characterized by multi source and multiple depositional systems. Due to the different cores, logging, test analysis and seismic data in different periods, the depositional system is very controversial. In the early study, the study area was dominated by underwater deposition and developed slowly slope fan delta braid delta lake. In recent studies, it is considered that the research area is on land exposed deposits and developed alluvial fan river sedimentary system. The lack of alluvial fan river sedimentary system makes drilling frequent loss, which seriously hinders the process of exploration and development of lithologic oil and gas reservoirs in the study area, and a new method is urgently needed to finely draw the sedimentary system and sand body characteristics. Under the guidance of sequence stratigraphy, applied sedimentology, reservoir geology, logging geology, seismic sedimentology, and so on, the isochronous sequence stratigraphic frame has been established on the basis of the combination of outcrop, logging and seismic data, and the typical sedimentary characteristics of the study area are established by seismic sedimentology. Through the detailed analysis of core sedimentology, the types of rock facies and sedimentary microfacies are divided, and sedimentary microfacies distribution, sedimentary patterns and sedimentary evolution characteristics are analyzed. On the basis of the classification of the genetic types of sand bodies, the pattern of sand body plane distribution, geometry, contact style and superposition mode are summarized and analyzed; finally, based on Goo The quantitative analysis of modern deposition by gle Earth, comprehensive use of stratigraphic section and logging data to quantify the sand body in the study area, and to elaborate the distribution characteristics of the favorable reservoir sand body and predict the favorable target area. The main understanding and conclusion obtained in this paper are as follows: on the basis of the analysis of paleogenomorphology, the source system analysis is based on the analysis of the paleogenomorphology. The zircon dating, heavy minerals, paleo flow and sand ratio are synthetically judged. (1) the dating results of zircon indicate that the age peak of the detrital zircon (400 Ma) in the study area is far from that of the northeastern aer Taishan (peak 505 Ma), which is inconsistent with the southern Tianshan (peak 313 Ma) and is in accordance with the Zaire mountain in the Northwest (peak 391 Ma), indicating that the Zaire mountain in the northwest is a study. The main source area of the study area; (2) the research area has two main sources of debris source: Northwest to northern direction and northeast direction; the early sediments in the Shawan Formation are north-west and northeast, mainly in the northeast direction; to the late Shawan Formation, the source direction is shifted to the north, and in the isochronous sequence stratigraphic framework, the sequence stratigraphy of the Vail sequence is in the classical sequence stratigraphy. Under the guidance of the theory, combining the outcrop, logging and seismic response characteristics, the high precision isochronous stratigraphic framework of the Neogene Shawan Formation of the spring light block is established, which is divided into 2 three order sequences (NSQ1, NSQ2) and 4 four order sequences. The top bottom interface of the Shawan Formation is all regional unconformable surface, the ground layer is overoverlying from the southeast to the northwest. The structure is relatively high, and the lower system domain is not developed. The.NSQ1 sequence is the main sequence of the lake invasion system tract and the high system tract, corresponding to the Sha Wan formation (N1s1), the sequence configuration is dominated by the lacustrine transgressive system tract (TST), and the high system tract (HST) is supplemented. The rock is coarser, the sedimentary multi stage thick sand conglomerate is low, and the NSQ2 sequence is the same. In the two section of Shawan Formation sand (N1s2) and three section of sand (N1s3), the sequence configuration feature is mainly high system domain (HST), and the lake invasion system domain (TST) is supplemented by the lacustrine system domain (TST), with fine sandstone, fine sandstone and small sand body thickness. In seismic sedimentology analysis, the corresponding relationship between seismic phase axis and lithology through 90 degree phase transformation is established, and rock physics is established through rock physics. The characteristics of sand shale identification are obtained by the relationship analysis; the typical stratigraphic sections are selected from bottom to top to be analyzed. The stratigraphic sections are irregular elliptical (rhombic) and dumbbell strongly negative amplitude abnormal body, and the multi period high curved channel amplitude abnormal body surrounds the irregular arched strong amplitude abnormal body distribution and a large number of thin and narrow amplitude abnormal body bands are calibrated. The sedimentary system is rich in the depositional system of the sandbank, edge beach and delta distributary channel. In petrological characteristics, the total debris content of the study area is high and the quartz content is relatively low, which is characterized by low maturity, and there are certain differences in its content in different wells. The point and line contact, mixed particle size and poor separation, is a low maturity feature of the near source. In the northeastern part of the study area, lithic feldspar sandstone and feldspar sandstone are the main features of the study area, with angle and sub angle like mineral complex support under the mirror, the separation is general and the maturity is low; in the middle part of the study area, the core of lithic feldspar sandstone and lithic sandstone is dominated by lithic sandstone and lithic sandstone. The sub - angled mineral complex support is characterized by low maturity; the southwest part of the study area is dominated by lithic feldspar sandstone, with relatively high quartz content and high maturity. Under the mirror, the angled and angular mineral complex support is generally selected. The Shawan Formation in the study area is divided into 7 types of rock facies through detailed core sedimentology analysis. Variegated block conglomerate facies, conglomerate sandstone rock facies, medium coarse sandstone rock facies, fine sandstone rock facies, gravel rock facies, mudstone facies and gypsum rock facies.5 logging facies: box, bell shaped, funnel-shaped, straight and straight shape. The whole is parallel subparallel, middle strong amplitude, middle and high frequency, medium good continuous seismic facies. Combined rock Facies, logging facies, seismic facies, single well facies and stratigraphic section response characteristics, the study area developed alluvial fan, braided river, meandering river, shallow water delta, fan delta and shore shallow lake 6 sedimentary system types and 24 sedimentary microfacies types, of which alluvial fan is dominated by fan end subfacies, developed braided channel, debris flow and microfacies sedimentary microfacies; braided river The subfacies of river bed subfacies, embankment subfacies and river diffuse subfacies are further subdivided into sedimentary microfacies of river bed retention, channel filling, heart beach, natural embankment and flood plain, and the quanduhe river is divided into river bed subfacies, embankment subfacies, river diffuse subfacies and yoke Lake subfacies, including river bed retention and sedimentation, river filling, bank, natural embankment, flood plain, abandoned River and so on The depositional system of the shallow water delta is further divided into delta plain and delta front subfacies, and the delta plain subfacies can be divided into distributary channel, inter branch Bay, abandoned channel and natural embankment, and the delta front can be further divided into subaqueous distributary channel, mat like sand, inter branch Bay and abandoned channel. Facies, fan deltas are subdivided into subfacies of front edge, subdivided into subaqueous distributary channel, inter channel and matting sand and other sedimentary microfacies. The lithology of different sedimentary microfacies, sand body thickness, logging facies and seismic response characteristics are analyzed. Sedimentary microfacies, sedimentary patterns, and sand body thickness differ greatly in different source areas, and sand bodies are different. The sand body development is not connected and the middle is the mudstone development zone. The vertical sand body development is uneven, the upward sand thickness is thinner and the connectivity is reduced; the sedimentary microfacies are complex, the sand one is dominated by braided river, the north-east south west direction is distributed, the northwest part develops small scale alluvial fan, the two section of the sand is early, the braided river turns to the meander river, and the border complex is developed in the south. At the end of the Department, the shallow water delta plain is deposited and the alluvial fan is still partially developed. With the continuous rise of the lake water and the migration of the source direction, the late sand two section, the northern fan delta, the southern shallow lake and the shallow water delta front edge, the three sediment period of the sand, the decline of the lake level, the alluvial fan in the north, and the southern development widespread in the south. Alluvial fan - braided river sedimentary model and fan delta shallow water delta depositional model are established. Single sand bodies are subdivided into shoals, flats, distributary channels, underwater distributary channels and matting sand. Different types of sand bodies have different responses to the development position, sand body characteristics, logging features and seismic reflection forms. The body is located at the bottom of Sha Wan formation at the bottom of the Shawan Formation in the study area. It has the characteristics of smooth flow flat front product and vertical multi stage hyperplastic body accumulation. The sand body is interposed and overlapped and often distributes. The lithology is mainly sand conglomerate, the sand body is thick, the average of the sand body is about 20m, and the multi stage sand body is stacked and sinked, and the well logging curve is mainly thick layer high amplitude box shape box shape. At the bottom of the body, the sediment is deposited in the river bed and the top of the sediment is deposited on the top. The seismic reflection is characterized by strong amplitude and low continuity. The strata are mostly irregular oval, rhombic or dumbbell shaped. The sand body of the beach is developed in two sand sections, which is the result of lateral migration of rivers and side accumulation of sediment. The mass content is high, the thickness of the single channel sand body is 3 m~15 m, the logging curve is medium and high amplitude gear box shape and wide finger shape. The seismic reflection is strong amplitude - medium good continuous. The stratum section is irregular arched strong amplitude abnormal body. The distributary channel sand body is the main sand body type in the shallow water delta plain. The lithology is thinner, with medium fine sandstone and gravel thin. The sandstone is the main type, and the separation grinding circle is good, the mud content is high and the local scour surface is seen. The thickness of the single sand body is medium to about 3 m~10 m. The logging curve is mainly wide finger and toothed box shape. The seismic reflection is strong amplitude - medium good continuous, lens like, thin and narrow strip in the stratum section, showing North East South West direction. The underwater distributary channel is shallow. The front edge skeleton sand body of the water delta is fine, with medium and fine sandstone with the thickness of medium and fine sandstone at about 5m, and the well logging curve is dominated by wide finger, medium and strong amplitude, medium good continuity and subparallel seismic facies. As a whole, the grain size is fine, with fine sandstone and siltstone, with thin sand body thickness, about 3 m, well logging curve as finger shape. Banded, dendritic, lenticular (POD like) and mat shape; sand body plane contact styles are mainly 4 types: lateral shear type, bay interval type, horizontal lap type and isolated type; sand body superposition style can be divided into 3 categories 5 small categories: stacking type, side stack and isolated type. With the increase of the level of the lake level and the value of the accommodating space / sediment flux (A/S), the structure of the sand body is transition from stacked to side stack and gradually to the isolated form. In the aspect of quantitative characterization of sand body, this study is based on the satellite photos, logging, seismic data, and the research area based on modern deposition. The main sand body is quantified. Through the measurement of the width of the river in the braided river in Maqu, the length and width of the heart beach, the width of the river and the length of the bank, the quantitative model is established and verified by the advantages of the high resolution of the stratigraphic section. It is shown that the model has good applicability. In addition, the shallow water delta is divided. The river channel has a clear response characteristic on the stratigraphic section. By calibrating the width of the river channel on the stratigraphic section and the corresponding thickness of the channel sand, the quantitative model of the width of the river and the thickness of the sand body is established. The number of complex facies reaches 0.82, which lays the foundation for the quantitative pre measurement of the sand body in the thin well network area. On the basis of detailed analysis of the distribution characteristics of the sand body, combining with the understanding of the sand body tip extinguishing zone, the quantitative study of sand body, the characteristics of hydrocarbon accumulation and seismic response, three favorable target areas have been screened.
【学位授予单位】：中国地质大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：P618.13

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