南鄱阳坳陷致密油成藏特征及其勘探前景

通过对南鄱阳坳陷所发现原油的储层孔渗特征、烃源岩地球化学特征、"源-储"接触关系、原油物理性质及原油显示特征进行分析,初步证明了所发现原油为致密油,确认了南鄱阳坳陷致密油的存在。结合南鄱阳坳陷致密油成藏地质要素、油源对比及流体包裹体成藏年代学研究,揭示了南鄱阳坳陷致密油的主要烃源岩为乐平组老山段含煤泥页岩,致密油为喜马拉雅早期成藏,总结了官山段致密油的成藏过程。在南鄱阳坳陷油气显示特征研究的基础上,初步总结出沉积相、烃源岩及断层为南鄱阳坳陷致密油的成藏主控因素。结合南鄱阳坳陷致密油的成藏条件及主控因素分析,总结了官山段致密油的富集规律,阐述了南鄱阳坳陷具备广阔的致密油勘探前景。     

盐城凹陷天然气成藏条件分析

盐城天然气属于高成熟源岩的裂解产物，主要来自古生界海相高成熟腐泥型源岩，朱家墩气藏主要的产气层系为阜宁组，泰州组碎屑岩储层，其中阜一段砂岩以Ⅱ类储层为主，Ⅰ类储层为次；泰州组以Ⅲ类储层为主，Ⅱ类储层为次，阜二段，阜一段中上部泥岩，泥灰岩，泰二段的泥岩和浦口组中上部含膏泥岩，在全区分布稳定，是良好的区域性盖层。盐城朱家墩地区主要分3个成藏层段，一是以阜宁组一段底部砂岩为主的构造气藏；二是以泰州组的较致密砂岩和玄武岩为主的岩性气藏；三是以中，古生界为主的气藏，盐城凹陷朱家墩天然气藏在具有良好盖层的储层段聚集成藏。朱家墩气藏成藏时期较晚，但与古生界二次生烃高峰时期一致，气源相对充足，而且储盖组合较好，但分布受控于深大断裂的发育以及储层的储集物性。     

辽河坳陷兴隆台油田成藏特征与成藏模式

利用地球化学、地质资料对辽河坳陷兴隆台地区的成藏特征进行了系统研究,认为研究区具有多油源供烃、多类型输导、多期次充注的特点。油源对比研究表明,油气主要来源于清水洼陷,其次为陈家洼陷,其中清水洼陷沙三段为主要烃源岩。含氮化合物指示油气沿着断层、砂体、不整合面等多种输导体,从生烃洼陷向构造高部位进行运移。流体包裹体与烃源岩生烃史显示研究区发生了多期成藏,主要成藏期为东营末期。综上,建立了以下3种成藏模式:潜山油气藏的"单源供烃、断层-不整合输导、早期成藏模式",沙三段油气藏的"自生自储、断层-浊积砂输导、早期成藏模式"和浅层沙二段、沙一段、东营组油气藏的"多源供烃、断层-砂体输导、晚期成藏模式"。     

济阳坳陷潜山油藏形成机理与成藏模式

在对济阳坳陷古生界潜山分布和油藏类型分析的基础上,通过对几个地区典型油气藏的解剖,研究了潜山油藏的成藏机理和成藏模式。综合分析认为潜山的成藏条件与所处的区域应力场环境、油气源条件、油气运移通道、反向断层的封堵及储集空间密切相关。依据潜山位置与烃源岩系接触关系及运移通道特征,把济阳坳陷潜山油藏成藏模式可归纳为它源（自源）-断块式潜山成藏模式、它源（自源）-褶皱式潜山成藏模式和它源-残丘式潜山成藏模式3种基本类型,分别论述了其基本特征、油气藏类型及典型实例,这对类似地区潜山的勘探具有理论和实际指导意义。     

胶莱坳陷莱阳组碎屑岩的成岩作用

莱阳组由砾岩，砂岩，泥岩，页岩等岩石组成。砂岩中出现赤铁矿，粘土矿物，方解石，石英及斜长石等五种主要的胶结物，它们形成于不同的成岩作用阶段。早期成岩阶段形成赤铁矿，粘土矿物，方解石和石英，晚期成岩阶段形成斜长石，而表生成岩阶段则再次沉淀出赤铁矿。     

济阳坳陷孤北低潜山煤成气成藏条件及特征

以往济阳坳陷所探明的天然气几乎均为油型气,为了打开济阳坳陷煤成气勘探局面,通过研究已获煤成气流的孤北低潜山成藏特征,在综合运用录井、岩心、地化分析、测井及地震等资料基础上,分析构造演化特征,结果显示：孤北低潜山上古生界经历了印支期抬升剥蚀、燕山期中生界沉积后的抬升剥蚀等多次改造,至喜山期受埕南及孤北断层控制大幅沉降沉积后在馆陶组沉积时期开始大量二次生气;而埕南、孤北断层明化镇组沉积早期停止活动更为气藏的保存提供了保障,该低潜山气源充足、储层条件好、盖层条件优越,具有形成煤成气藏的条件。结果认为：本区气藏具有自生自储、上生下储和上生侧储3种运聚方式,除孤北低潜山的上古生界气藏之外,该区的下古生界风化壳和该区以南孤岛凸起的下古生界也是煤成气藏勘探的重要领域。     

临清坳陷东部构造类型及成藏规律分析

临清坳陷东部为一中新生代大陆裂谷盆地,实测并系统分析了盆地内７种与油气聚集有关的基本构造类型及其叠加形式,探讨其成因机制和分布规律,最后结合生、储、盖层条件分析油气聚集的基本规律,指出了有利的勘探方向。     

松南气田登娄库—泉头组天然气成藏特征分析

松南气田位于松辽盆地南部长岭断陷中央隆起带达尔罕断凸带腰英台深层构造高部位.通过分析解剖烃源岩、输导等,认为松南气田登娄库—泉头组天然气藏具有双向供烃的特征;达尔罕断裂是控制气藏规模的主断裂,它的开启与封闭直接决定天然气藏的形成保存及破坏散失.在典型气藏解剖的基础上,综合油气成藏条件,总结了成藏规律：多期生烃,北、西次凹供烃、近距离运移,长期运移指向、聚集,深层储盖组合匹配.     

南黄海盆地南部坳陷二叠系龙潭组—大隆组沉积相

南黄海盆地位于下扬子地块的东部,中、古生界研究程度较低,迄今为止尚未系统开展过龙潭组-大隆组沉积相研究,从而制约了研究区的油气勘探。本次研究结合陆上下扬子的研究成果,通过实际的钻井、地震资料分析,开展了南黄海盆地南部坳陷龙潭组-大隆组沉积相研究。结果表明:龙潭组-大隆组沉积时期研究区发育海相碎屑岩沉积,沉积体系整体呈NE向展布;自NW向SE方向水体逐渐变深;研究区的东北部发育河流相,向SE方向过渡为三角洲相、沼泽-澙湖相和前滨-临滨相,东南部为陆棚相;该套地层泥岩和煤层发育,属于良好烃源岩。     

苏北盆地盐城组天然气藏成藏条件及控制因素探讨

苏北盆地天然气资源丰富,已经在盐城组发现两个气田———周庄气田和溪桥气田。盐城组天然气藏埋藏浅(<1000m),研究盐城组天然气的成藏条件及控制因素,对苏北盆地的下步勘探具有非常现实的指导意义。全面阐述了苏北盆地盐城组的成藏条件,探讨了其成藏的控制因素。通过研究,认为苏北盆地盐城组本身虽不具备生烃条件,但储盖条件较好,下部烃源岩生成的天然气沿断层向上运移,在盐城组圈闭配置理想的条件下形成气藏。天然气藏受气源、生气强度、断裂和盖层4个因素控制。     

Influence of natural fractures on gas accumulation in the Upper Triassic tight gas sandstones in the northwestern Sichuan Basin,China

The Upper Triassic Xujiahe Formation in the northwestern Sichuan Basin, China, is a typical tight gas sandstone reservoir that contains natural fractures and has an average porosity of 1.10% and air permeability less than 0.1 md because of compaction and cementation. According to outcrops, cores and image logs, three types of natural fractures, namely, tectonic, diagenetic and overpressure-related fractures, have developed in the tight gas sandstones. The tectonic fractures include small faults, intraformational shear fractures and horizontal shear fractures, whereas the diagenetic fractures mainly include bed-parallel fractures. According to thin sections, the microfractures also include tectonic, diagenetic and overpressure-related microfractures. The diagenetic microfractures consist of transgranular, intragranular and grain-boundary fractures. Among these fractures, intraformational shear fractures, horizontal shear fractures and small faults are predominant and significant for fluid movement. Based on the Monte Carlo method, these intraformational shear fractures and horizontal shear fractures improve the reservoir porosity and permeability, thus serving as an important storage space and primary fluid-flow channels in the tight sandstones. The small faults may provide seepage channels in adjacent layers by cutting through layers. In addition, these intragranular and grain-boundary fractures increase the connectivity of the tight gas sandstones by linking tiny pores. The tectonic microfractures improve the seepage capability of the tight gas sandstones to some extent. Low-dip angle fractures are more abundant in the T₃X³ member than in the T₃X² and T₃X⁴ members. The fracture intensities of the sandstones in the T₃X³ member are greater than those in the T₃X² and T₃X⁴ members. The fracture intensities do not always decrease with increasing bed thickness for the tight sandstones. When the bed thickness of the tight sandstones is less than 1.0 m, the fracture intensities increase with increasing bed thickness in the T₃X³ member. Fluid inclusion evidence and burial history analysis indicate that the tectonic fractures developed over three periods. The first period was at the end of the Triassic to the Early Jurassic. The tectonic fractures developed during oil generation but before the matrix's porosity and permeability reduced, which suggests that these tectonic fractures could provide seepage channels for oil migration and accumulation. The second period was at the end of the Cretaceous after the matrix's porosity and permeability reduced but during peak gas generation, which indicates that gas mainly migrated and accumulated in the tectonic fractures. The third period was at the end of the Eogene to the Early Neogene. The tectonic fractures could provide seepage channels for secondary gas migration and accumulation from the Upper Triassic Xujiahe Formation into the overlying Jurassic Formation.     

歧口凹陷东北环天然气成藏条件与勘探领域

歧口凹陷是渤海湾盆地重要的生气凹陷,存在石炭-二叠系和古近系沙河街组两套生气层系,凹陷东北环紧邻歧口凹陷主洼,具备形成大型天然气田的物质基础。在古近纪沉积时期受三个方向物源的影响,储盖组合较发育,沙河街组的超压又较好的保存了储层物性。通过对构造特征、沉积体系和油气运移条件分析,认为凹陷东北环深层构造圈闭、沙垒田凸起西翼倾没端地层圈闭和深层岩性圈闭是该区天然气勘探的重要领域和方向。     

四川盆地西南地区下三叠统嘉陵江组沉积相研究

通过对钻井岩心和测井等资料的研究,认为川西南地区下三叠统嘉陵江组存在着混积潮坪、开阔台地、局限台地和蒸发台地4种沉积相类型。嘉一期主要发育混积潮坪相和开阔台地相,嘉三期主要发育开阔台地相,嘉二、嘉四、嘉五期主要发育局限台地和蒸发台地相。选取并研究地层厚度、灰岩厚度、白云岩厚度和颗粒岩厚度等四种能反映沉积环境和沉积相的地质因素,指出了每个层段的沉积相平面分布特征。     

天然气水合物的形成与识别

探讨了天然气水合物矿藏的形成条件和机理、水合物矿藏的聚集方式。天然气水合物的形成除了必要的气体和水,还需要一定的温压和地质条件;其形成机理可用高渗漏系统和弱渗漏系统来解释;天然气水合物在沉积物中主要以构造聚集和地层聚集的方式存在。综述了天然气水合物矿藏的识别方法。     

Hydrothermal dolomite reservoir in the Precambrian Dengying Formation of central Sichuan Basin,Southwestern China

The Precambrian Dengying Formation is maximum buried carbonate reservoir in the Sichuan Basin. Reservoir types are thought to be dominated by sedimentary facies or karst controlled. Precursory sedimentary fabrics have been intensively superimposed by medium-to coarse-grained dolomite in most areas. Dolomitized intervals contain planar and saddle dolomite, quartz, and few hydrothermal replacive minerals. Fluid inclusion analyses of dolomite suggests that rocks are formed at temperatures ranging from 132.6°C to 218.7°C in the presence of dense brines, while the dolomite phases are demonstrated by negative δ¹⁸O and δ¹³C VPDB values. Strontium isotopes enriched in ⁸⁷Sr, and the fluid source could support the conclusion. The dolomites of the Dengying Formation in central Sichuan Basin that formed around basement-rooted wrench faults, in turn mainly oriented towards the North-South and East-West strike-slip faults, are detectable. Lastly, the grabens take the form of negative flower structures-the result of an intra-cratonic rift that took place during the Sinian and early Cambrian period through tensional faulting.Our primary contention is that basement fault, which resulted in the magmatic or deep clastic fluids migration, was key for the formation of the obvious high-temperature coarse dolomite and saddle dolomite replacement. Subsequently, hot fluids that circulated within the matrix dolomite were aided by fractures or vugs and (1) leached into the dolomite, producing vugs and pores; (2) precipitated saddle dolomite, and (3) led to hydrofracturing, fractures enlargement, and further brecciation. The dolomite eventually formed porous hydrocarbon reservoirs through diagenesis. This model better illustrates how fluids that originated from deep basin migration along strike-slip transfer faults and fractures flowed out to structures in Precambrian basement-rooted faults, inheriting the rift in the Cambrian. The data involved offers a fresh perspective pertinent to deep hydrocarbon exploration of dolomite reservoirs in Southwestern China.     

川东板东构造长兴组生物礁及其地震特征研究

根据板东构造板东4井等长兴组钻探资料,对长兴组的生物礁进行了研究。研究表明板东构造长兴组储集岩有生物（屑）泥晶灰岩-含生物（屑）泥晶灰岩、礁灰岩和白云岩。综合储集岩物性特征、区域钻、测井资料及野外剖面,总结了生物礁的形成与演化模式及模式各部位所对应的岩性和物性。通过地震响应特征、反演等技术建立了长兴组储层识别模式,利用对应速度、Landmark属性提取的储层有效厚度经计算机网格化编制出了长兴组储层厚度分布预测图,与钻测井厚度对比,证实板东4井生物礁为点礁。     

琼东南盆地深水区L18气田上新统地层圈闭气田形成条件及成藏模式

近期在琼东南盆地超深水区发现了L18气田上新统地层圈闭气田,但在聚气背景、烃源岩、储层沉积成因及天然气输导体系等气田形成条件和成藏模式认识存在争议。通过对该气田形成条件的综合分析,认为上新世轴向古洼槽内地层圈闭、陵水凹陷东洼下渐新统崖城组浅海相烃源岩、上新统限制型重力流砂岩储层和渐新统-中新统断裂垂向沟源通道是形成上新统地层圈闭气田的4个基本条件。中中新世以来盆地中央继承性发育轴向古洼槽和限制型重力流沉积,随着后期地层沉积迁移、差异压实作用,上新统莺歌海组砂岩顶面在轴向洼槽内起伏,并被周边泥岩封盖、封堵,形成了地层圈闭;约3.4 Ma BP,陵水凹陷东洼下渐新统崖城组浅海相烃源岩生成了成熟天然气,沿渐新统-中新统断裂向上运移到上新统莺歌海组重力流沉积砂岩中,再侧向运移至地层圈闭中聚集成藏,具有"烃源岩、圈闭、断裂+砂岩输导层"三要素控藏的上新统地层圈闭成藏模式。     

西湖凹陷Y构造花港组气藏特征及成藏主控因素

以常规和非常规油气成藏理论为指导,结合储层、流体等测试分析结果,开展西湖凹陷Y构造花港组气藏特征及成藏主控因素研究。结果表明：① 花港组垂向上符合中下部致密砂岩气、上部常规天然气藏的分布序列;② 常规气藏气水关系正常,受断盖配置对沿断裂运移油气的封闭作用和断层侧向封堵能力影响,油气主要在区域盖层之下的断背斜顶部富集;③ 致密气藏具叠覆跨越源储组合关系,含气饱和度低,无明显气水界面,属先致密后成藏类型,不同部位含气性受构造幅度和储层物性共同控制。本次研究丰富和完善了西湖凹陷常规-非常规天然气序列成藏规律,并为致密砂岩气的勘探提供理论指导。     

An inland facies-controlled eogenetic karst of the carbonate reservoir in the Middle Permian Maokou Formation,southern Sichuan Basin,SW China

Carbonate karst is one of the research highlights in the field of carbonate reservoir geology. Here, we report on a new type of karst formed in the Middle Permian Maokou Formation, southern Sichuan Basin, SW China, i.e., inland facies-controlled eogenetic karst, which is different from the previously defined telogenetic karst. This karst is eogenetic as the formation was buried at shallow depths prior to being subaerially exposed for a period of 7–8 Myr, in the paleo-continental region of the Upper Yangtze Uplift. Subaerial exposure may have been caused by a sea level regression during the Tungwu Orogeny, which gave rise to a depositional hiatus over a broad area. The top of the Maokou Formation is commonly marked by a weathered crust and an unconformable relationship with overlying layers. Below the surface, the Maokou Formation contains sediments deposited by an underground drainage. The geological setting can be inferred from an inland karst far from coastline. The subsurface karst interval consists mainly of coarse-grained limestone and micrite, with the former occurring in shoal facies deposited in a high-energy depositional environment, and the latter in non-shoal facies deposited in a low-energy environment. Both of them were interbedded with in variable thicknesses. The coarse-grained limestone layers with high porosity and permeability acted as inception horizons, more favourable for the development of karst than the micritic layers with low porosity and permeability. Therefore, in places where both coarse-grained limestone and micrite are present, the karst is considered to be facies-controlled. The primary permeability of the coarse-grained limestone, combined with the permeability provided by faults and fractures, provides sufficient channels for karst water. Formation of the karst system was characterized by contemporaneous development at multiple levels, as controlled by the stratigraphic position of coarse-grained shoal facies. The karst reservoir therefore developed in both karst highland and karst transitional zone (area between the karst highland and karst basin). According to this model of karstification, hydrocarbon exploration should focus on karst highlands located on palaeohighs and in synclines located far from fault zones.