【作者】 马文睿；

【导师】 傅强；

【作者基本信息】 同济大学 ， 石油地质， 2014， 博士

【摘要】 高邮凹陷是苏北盆地各凹陷中油气资源最丰富的凹陷，具有极其重要的工业价值。近年来，苏北盆地高邮凹陷勘探实践的不断深入，新发现构造类油气圈闭的数量逐年下降，而发现的岩性圈闭数量则日益增加，勘探重点正在逐步从构造圈闭向岩性圈闭转变，因此在凹陷内通过沉积学、构造学方面的研究来寻找有利砂体和通过石油地质学的研究来寻找油气藏成藏特征、规律进而帮助寻找有利圈闭的任务显得尤为重要。苏北盆地高邮凹陷是中生代晚白垩世—新生代古近纪断坳、断陷作用形成的陆相断陷湖盆，具有断层发育、构造复杂的特征；黄珏-马家嘴地区位于该凹陷西南端，与高邮凹陷大体上有相同的构造演化特征；由于研究区处在凹陷内的两条控凹断裂—真武、汉留断层的结合部，两组倾向相反的主断层使研究区构造体系更加复杂；黄珏-马家嘴地区戴南组沉积地层为一被断层复杂化的小型断块油气田，具有断块破碎、沉积砂体分布复杂、油气藏分布凌乱的特征，多年来一直困扰着该地区的勘探与开发。黄珏、马家嘴地区虽然在地理上相邻相连，但勘探开发中一直将黄珏、马家嘴两个地区分别研究，在研究过程中尚未对其构造、沉积、储层、油气藏进行过整体的研究，此次研究正是在在整合岩心、测井、岩石分析化验、地震、构造、地化等资料的基础上，从构造研究出发，对物源方向、沉积相、沉积砂体成因机制等有关沉积学方面内容开展研究，在此基础上就成岩演化作用对储层影响进行探讨；结合沉积展布规律，对烃源岩、输导、油气藏形成过程、油气分布规律进行了综合分析。常规的物源分析方法通常是利用矿物指标等对物源进行面上方向的分析，此次研究除利用沉积学法、岩石学法、重矿物法外，还通过“矿物定区、构造定向”的方法进行，综合了构造样式与物源输送的关系对物源进行细致刻画。通过地震剖面及断层平面组合形式识别出了断槽、断裂调节带、下切河谷等沟谷输送体系，以及断阶、陡坡型坡折输送体系；沟谷、坡折是碎屑物质输送的良好渠道，两类输送体系对沉积物的输送都具有极其重要的作用，控制了沉积物输送的方向与沉积砂体的厚度；通过对黄珏-马家嘴地区戴南组两个层段的重矿物、岩矿组分的分析，对沉积物的物源方向进行了面上的划分，认识到物源主要来自南、北、西三大方向；结合物源输送通道的研究，认为物源输送的具体细节是由构造活动背景下形成的沟谷、坡折带输送体系决定的，具有“构造控制沉积输送方向”的特点。基于点-线-面-体-时的研究过程和抓住重点、不放疑点的思想，对黄珏-马家嘴地区戴南组沉积特征进行研究。通过对黄珏-马家嘴地区戴南组沉积特征的分析研究，认为黄珏-马家嘴地区戴南组沉积具有“水体涨落控制沉积相类型”的特点。具体归纳为黄珏-马家嘴地区戴一段湖平面上升，发育了近源的近岸水下冲积扇沉积、湖泊沉积、滑塌-浊积扇沉积；戴二段水体逐步退去，发育了退积型扇三角洲沉积、湖泊沉积、滑塌-浊积扇沉积；在沉积构造与水动力条件关系研究的基础上，进一步分析了这些沉积砂体的成因机制。研究区戴南组地层中主要发育了牵引流和重力流影响下的沉积砂体。对比他人研究成果，对一些存疑的特殊沉积构造进行再研究，识别出了古震和古风暴作用的痕迹，很好地解释了黄珏-马家嘴湖区深凹中新发现的滑塌-浊积扇岩性油藏砂体的成因，认为“重力失衡、外力激发是滑塌-浊积扇发育的促因”，为该地区今后岩性油藏勘探开发提供了方向。通过单井剖面、联井剖面、平面、模式等的综合研究，对黄珏-马家嘴地区的沉积进行了详细的研究。抛开地层单位的局限，将黄珏-马家嘴地区储层按埋深进行研究，通过对黄珏-马家嘴地区戴南组储层物性特征和储层成岩演化阶段的研究，发现储层物性特征与储层所处的深度具有明显的相关性，储层物性与所处层段的关系并不强，由于黄珏-马家嘴地区戴南组各个层段所处的埋深不同，造成储层所处的温压场和地层水化学作用不同，储层所经历的成岩阶段也不尽相同；纵向上，处于成岩早A期-早B期的储层由于压实及胶结作用，储层物性随深度逐渐变差，而进入成岩中A期的储层受次生溶蚀等作用能够改造储层，使因压实作用减少的孔隙得到一定的恢复，因此成岩演化体现出埋深较深的黄-马东部地区成岩作用阶段高于埋深较浅的西部，同理南北两侧的成岩阶段高于中间的特征。沉积相对储层物性平面分布上的影响比较突出，扇三角洲前缘、近岸水下冲积扇扇中等沉积亚相发育的储层具有比其它亚相更好的物性特征。体现了“沉积相控制储层、深度控制成岩作用”。以早A、早B、中A、中B期四个成岩阶叠合Ⅱ、Ⅲ类储层类型对研究区储层进行“成岩-物性相”的研究和划分；其中有利储层主要为Ⅱ类储层，构成良好储集性能的储积体，这类储层在早、中成岩阶段都有出现。通过对盖层封闭能力和储、盖系统时空分部的分析，认为黄珏-马家嘴地区的多套储集层和盖层组合具有良好的匹配关系，形成了多套良好的储-盖组合。对整个凹陷内烃源岩层系进行了排查比对，认为阜四段烃源岩是凹陷戴南组主要的烃源岩层系，有机质类型为Ⅰ、Ⅱ型，为极好的烃源岩；结合油源对比资料的基础上，认为邵伯次凹发育的阜四段烃源岩是为黄珏-马家嘴地区戴南组油气藏的供烃的主要烃源岩层系；通过对阜四段烃源岩Ro%、氯仿沥青“A”、HC、TOC、S1+S2等参数的研究，认为研究黄珏-马家嘴地区阜四段烃源岩具有有机质类型好、丰度高、有机质演化程度高的特点，是研究区戴南组的主力供烃来源。油气成藏的特征的研究围绕着油气输导和保存的问题开展，输导体系，尤其是断层输导体系在断陷盆地油气成藏过程中扮演了重要的角色。通过对骨架砂体、断层、不整合面以及三者的组合形式所形成的油气输导体系进行了分析和评价。各级断层在油气输导中起到不同的作用：一、二级断层活动时沟通烃源岩层系，静止期起到封堵作用；三、四级断层具有一定的控藏能力；静止期的三、四级断层封堵油气，活动期的三、四级断层调节再平衡油气分布。有利相带中沉积砂体的时空展布控制了油气藏的平面展布。可将油气成藏过程概括为“大断层切穿源岩主力输导，小断层阻断运移进行封闭；砂体约束油气平面展布、活动断层进行重新分配”。通过研究，认为发育于深湖区的滑塌-浊积扇有着良好的烃源岩-储层-盖层匹配关系，扇三角洲前缘以及近岸水下冲积扇扇端沉积在重力作用下失稳，发生滑落、崩塌及在古震-风暴激发下形成的“滑塌-浊积扇”将成为未来寻找岩性油气藏的重点和希望所在。更多还原

【Abstract】 Gaoyou sag in Subei basin has the largest amount of petroleum resources，which has great industrial values. In recent years of exploration, the number of newlyexplored structural oil and gas traps decreased while the number of foundedlithological traps increased gradually. The key point of exploration is varying fromstructural traps to subtle ones. Finding favorable sands by the methods ofsedimentology and understanding the characters and laws of hydrocarbonaccumulation in the sag became more and more important.Gaoyou sag in subei basin is a terrestrial rift-subsidence lacustrine basin formedfrom Late Cretaceous Period to Paleocene. Huangjue-majiazui district, with theconsistent tectonic evolution characteristics of the whole depression, lays on the westpart of Gaoyou sag, but has a much more complicated tectonic evolution processcaused by the two big controlling faults(Zhengwu&Hanliu fault zone) passedthrough this district. The research target is a small fault-complicated fault-blockoil-gas field, with properties of broken blocks, complicated sand and hydrocarbonaccumulation distribution. Exploring and developing process was plagued by thosefactors above.Even though Huangjue and Majiazui district were geographically nearby, theresearch work of the two districts were separated for decades, while the research onstructure, sedimentary, reservoirs, oil and gas accumulations are unrelated. But thispaper discussed the provenance, sedimentary facies, and genetic mechanism of sandbodies based on tectonic evolution by the integration geological materials of cores,well-logging data, seismic data, and tectonic evolution information and so on as awhole. The genesis of reservoir evolution is discussed after those researches. With thedistribution of sedimentaries, source rocks, hydrocarbon transport system,hydrocarbon accumulating process, and the distribution of petroleum were studied.Normal research on provenance was mainly based on mineral indexes, anddivided the provenance directions. In this paper, the methods of provenance researchis not only based on minerals but also combined with structural geology ways todescribe the details of provenance. With explained seismic profiles and planecombination forms of faults, fault troughs, fault accommodation zones and incisedvalley transportation systems were recognized. Fault-step slopes and steep slopes transportation systems were found as well. All those transportation systems had greatability on transporting debris, and also controlled the direction of transportationdirections and the thickness of sediments. According to stable heavy minerals andmineral compositions, three directions were described, which came from south, northand west. With the structural researches, the details of provenance were depicted.Architectural patterns of structure determined the paths of provenance.The sedimentary characters were studied based on the process of“points-lines-surfaces-bodies”. With the idea of keep the importance and not let go thesuspects, we believed that the sedimentary facies has the attributes of controlling byrise and fall of water surface. In E2d1period, lake-level rose, it developed near-shoresubaqueous alluvial fan, lacustrine, and slump-turbidity fans facies. Up to E2d2period,lake-level fell; it developed fan deltas, lacustrine, and slump-turbidity fan facies.Based on the relationship of hydrodynamic conditions and tectonics, the causes andmechanism of sands were researched. Sands under the influence of tractive currentand gravity flows developed in the area of Dainan formation. Compared with theresults of previous studies, some suspected sedimentary structures were studied.Paleo-earthquakes and paleo-storms were identified. Those phenomenons andessences explained the sands found in deep-lake muds. It is considered that gravityimbalance and external excitation caused the slump-turbidity fans forming. A newdirection for oil and gas exploration was provided.Despite the limitations of formations and layers, the reservoirs were studied. Bythe characters and digenesis process, we found the physical property of reservoirs isnot determined by formations but mainly by the burial depth they lay. Differentchemical action caused by temperature field and formation water chemical acts causedby different burial depth of different formation in Huangjue and Majiazui district; thedigenesis of reservoirs were different. In vertical dimension, compaction andcementation which happened in early diagenesis stage A to B decreased the porosityand permeability until middle diagenesis stage A, and then secondary dissolutionbegan to enlarge the pores and improve permeability. With the different buried depth,it shows the phenomenon that diagenesis stage in the east is higher than the west, thenorth and south are higher than the middle. Sedimentary facies controlled the physicalproperties on ichnography. Reservoirs of those subfacies, such as Fan Delta Front,Near-shore Subaqueous Alluvial Fan Middle, have better physical properties than onthe other subfacies. All those above cases were concluded the feature of “sedimentary controlled reservoirs” and “buried depth controlled diagenesis”. Using physicalproperties “styleⅡ and Ⅲ” coupled with diagenesis stages “EA, EB, MA, MB”,“styleⅡ” are the favorable reservoirs and this kind of reservoirs appeared at early tomiddle stages. Reservoirs and seals well matched in research area, formed severalgood reservoir-seal combinations.Based on the previous data investigation and comparison of source rocks, E1f4formation is considered to contain the best source rocks in Gaoyou sag and is the besthydrocarbon provider for Dainan formation with the organic matter of typeⅠand typeⅡ. After oil-and-source-rock-correlation research, source rocks in Shaobo Sub-sagwas confirmed as the main source rocks for Dainan formation in research area, whichdeveloped nearest at research area. They were considered of the best type of organics,high in organic matter, and evolution, after studied the index of “Ro”,“chloroformbitumen “A””,“HC”,“TOC”,“S1+S2”, et.al.The research of hydrocarbon accumulation is mainly about oil and gastransporting system and oil-gas preservation. Transporting system, especially the faulttransporting system, played a very important role in petroleum transporting of a faultbasin. Oil and gas transporting system made of skeleton sand bodies, faults,unconformities and their combination forms were studied and evaluated. Faults ofdifferent level have different effect ions. Level1and2faults connected source rocksand reservoirs when they were activated while static period they sealed the oil and gas.Level2and3faults have certain capability on controlling oil and gas accumulations.They adjusted and rebalanced oil and gas distributions when active or sealed whenmotionless. Space-time distributions of favorable facies belts controlled thehydrocarbons. It can concluded that faults of high level cut through source rocks andtransferred hydrocarbons, small and low-level faults seal while sand-bodies restrainedthe plane distribution and rebalanced existed hydrocarbon reservoirs.Slump-turbidity fans developed in deep lake zone produced the play ofsource-rocks, reservoirs, and seals through the research, those sandstones originatedfrom fan delta front or near-shore subaqueous alluvial fan middle, under the externalforce of earthquakes or hurricanes or internal force of gravity, will one day becomethe new hope and focal point for further exploration on lithological reservoirs.更多还原