渤海新近纪古湖发育的直接证据

通过渤海5口钻井的沉积有机质分析,以沉积有机质中浮游藻类丰度和类型、无定形有机质含量变化以及地层序列中富藻沉积层发育程度。作为指示湖相沉积环境发育的标志,确定渤海新近纪湖相沉积层的分布特征及渤海古坳陷湖的发育特征。分析表明,浮游藻类和无定形有机质含量高的层段在馆陶组和明下段都有分布,但发育最好的是在明下段下部。这是渤海新近纪湖相沉积地层存在的直接证据。从湖相沉积发育的差异看,馆陶组和明化镇组时期的古湖有着不同的特征,馆陶组早期渤海的湖泊可能很小,馆陶组中、晚期为湖泊扩张期,从含浮游藻类和无定形有机质沉积层纵向变化频繁出现可以看出浅湖沉积环境的不稳定性。新近纪古湖的盛期是在明下段下部沉积时段,当时渤海淡水湖泊普遍存在。     

北部湾盆地涠西南凹陷W区流沙港组储层非均质性研究及应用

基于沉积微相研究和测井精细解释数据统计分析,开展了涠西南凹陷W区古近系始新统流沙港组储层非均质性研究.W区储层为流一段和流三段,沉积微相研究表明,流沙港组主要为正常三角洲相和扇三角洲相沉积.储层夹层岩性主要为泥岩、粉砂质泥岩,主要成因为分流水道间、水下分流河道与砂坝、砂坝与砂坝、辫流坝与辫状水道、辫状水道间的泥质沉积物...     

北部湾盆地涠西南凹陷C洼烃源岩热史及成熟史模拟

北部湾盆地涠西南凹陷C洼流沙港组烃源岩热史及成熟史研究,对C洼深水油气勘探具有指导意义。在恢复涠西南凹陷C洼地史和热史的基础上,利用EASY%Ro模型计算了流沙港组烃源岩的成熟度史。研究结果表明,在涠西南凹陷发展的裂陷阶段初始期热流值较高,最大值约为77mW/m2,其后热流值逐渐减小,现今热流值约为54mW/m2;涠西南凹陷C洼流沙港组烃源岩开始生烃(Ro=0.5%)时间为51MaBP,达到生烃高峰(Ro=1%)时间为42MaBP,达到高成熟演化阶段(Ro=1.3%)时间为17MaBP;对比涠1井流沙港组烃源岩演化特征,处于C洼深水勘探区的流沙港组烃源岩成熟度较高,生烃能力较强,拥有广阔的油气勘探前景。     

乌石凹陷含油气远景

乌石凹陷是北部湾盆地的一个以下第三系沉积为主的生油凹陷。主要生油层流沙港组泥页岩生油指标高、厚度大、分布面积广,具有丰富的油气源;在早第三纪已形成的四个局部构造带为有利的油气聚集场所。凹陷东部流沙港组存在高压异常,而凹陷西部存在流沙港组与涠洲组两套烃源岩。     

南海北部北部湾盆地迈陈凹陷中南部X井油气成藏地质条件

根据X井钻遇的古近系和新近系有机质镜质体反射率分析,确定X井生烃门限深度在2 600m以下,那么该井钻遇始新统流沙港组泥岩有机质丰度较高的井段（2 100~2 285m）尚未达成熟门槛,而生烃门限以下的烃源岩有机质丰度较低,生烃潜力差,不能提供充足的烃源供给,故导致X井勘探失利。X井位于北部湾盆地迈陈凹陷东3洼南部边缘,钻遇流沙港组厚度达568.5m,且泥岩厚度占该组地层的62.3%,其中单层泥岩最大厚度高达115m,表明流沙港组沉积时期水体环境偏深,沉积可容空间大,可见X井钻探结果与前人＂迈5号同生断裂始新世活动弱,沉积可容空间小,导致东3洼缺少油气形成的物质基础＂的结论存在较大偏差。由于X井处在东3洼陷边缘,流沙港组顶部剥蚀强度较大,推测靠近东3洼沉降中心的始新统流沙港组湖相泥岩沉积厚,埋深亦加大,完全能够达到有机质成熟生烃门槛,故应具有较好的油气成藏地质条件和勘探潜力。     

涠西南凹陷C洼油气成藏动力学过程与充注历史

以油气成藏体系及成藏动力学理论为指导,在成藏基本地质要素分析的基础上,综合各种地质、地球物理、地球化学等资料,采用盆地数值模拟与油气地质综合分析相结合的研究方法,分析了涠西南凹陷C洼的流体动力场特征,动态重建了油气成藏动力学过程,恢复了流体充注历史。结果表明:C洼地区具有较高的地温梯度,流沙港组二段发育有异常超压,古今流体势分布具有较大的继承性;该区沉积充填与构造沉降具幕式变化特征,流二段烃源岩目前处于成熟—高成熟阶段,具有较高的生排烃速率,主要生排烃过程发生于中新世以来;C洼地区经历多次油气充注过程,其中东北部以早期为主,西南部以晚期充注为主。     

北部湾盆地北部坳陷古近纪原型结构分析

北部湾盆地北部坳陷古近纪受多期次构造运动的影响,后期改造强烈.从现今构造格局出发,通过剥蚀量恢复并结合断裂活动特征,进行了北部湾盆地北部坳陷古近纪原型结构重建及成凹机制探讨.认为北部湾盆地北部坳陷古近系沉积沉降中心在时空上呈现由西向东和由北向南的迁移特征;始新世流沙港组沉积时期涠西南凹陷D次凹与海中凹陷的西洼为同一沉积单元;断裂和隆起联合控制了洼陷的基本形态,特别是涠西南低凸起的活动对北部坳陷古近纪统一湖盆的分割起关键作用.     

白令海北部陆坡23 ka以来古生产力变化及其对海冰扩张的响应

本文基于白令海北部陆坡ARC6-B11岩心的沉积物粒度、颜色反射率、有机碳/氮含量和高分辨率化学元素XRF扫描数据,结合底栖和浮游有孔虫AMS14C测年资料,重建了研究区23 ka以来至中全新世的沉积记录,重点研究了海冰的扩张变化对生产力和沉积物输入的影响。研究结果显示,末次盛冰期白令海北部陆坡受到海冰南向扩张的影响而生产力较低,沉积物中砂粒级和冰筏碎屑（IRD）含量较高。HS 1时期由于受到常年冰的覆盖,沉积物中砂粒级和IRD含量存在低值,沉积物中较高的总有机碳（TOC）含量受陆源有机质的影响较大,异常的TOC含量峰值主要受到低海平面和海冰形成过程产生的富氧水团控制下的高浓度细粒物质携带的陆源有机质的快速沉积作用的影响,难以作为反映白令海古生产力的替代指标。B/A暖期和全新世生产力较高,在B/A暖期存在Ca/Ti峰值现象,Ca/Ti峰值现象的产生与碳酸盐补偿深度增加有关,水体通风条件的改变可能起到一定的作用,也不能忽视颗石藻对其产生的潜在影响。     

南海中部海区浮游有孔虫的溶解——碳酸盐溶解作用初探

深海碳酸盐溶解作用是海洋沉积学研究的重要内容之一。众所周知有孔虫遗壳是深海底质碳酸盐沉积的主要来源,浮游有孔虫壳的存在与沉积物中碳酸钙的含量密切相关。了解浮游有孔虫的被溶蚀情况,对了解深海碳酸盐溶解作用具有重要意义。 本文根据南海中部海区表层沉积物中浮游有孔虫的分布和碳酸钙含量的分析,对该海区的碳酸盐溶解作用和主要界面的深度作初步探讨。     

广东省典型海湾表层沉积有机质的来源和分布

于2009年对广东省3个典型海湾湛江港、深圳湾和流沙湾表层沉积物的稳定碳同位素进行了分析。结果显示,湛江港表层沉积物δ13C值的范围为25.9‰—23.9‰,平均值为25.2‰;深圳湾表层沉积物的δ13C值的范围为25.9‰—23.2‰,平均值为25.1‰;流沙湾表层沉积物的δ13C值的范围为23.2‰—20.0‰,平均值为20.9‰。根据经典二元模式计算,湛江港陆源有机质的贡献比例范围为0.57—0.90,平均为0.78;深圳湾陆源有机质的贡献比例范围为0.45—0.90,平均为0.76;而流沙湾表层沉积有机质中海洋有机质的贡献比例较大,陆源有机质的贡献比例很小。湛江港和深圳湾表层沉积有机质主要来源于陆架,可能是C3(光合作用最初产物为三碳化合物)植物和海洋浮游微藻的混合有机质,但起主导作用的是陆架C3植物;而流沙湾表层沉积有机质主要来源于大型海藻和贝类的排泄物。各海湾沉积有机质的分布没有明显的规律性,主要受大陆径流、航运和潮汐的影响,同时也受海域初级生产力和水产养殖业的影响。     

Petroleum geochemistry and depositional setting of lacustrine source rocks

Lacustrine sequences are increasingly being recognised as hosts for commercial reserves of petroleum. Petroleum source rocks in lacustrine sequences have organic carbon contents ranging from <1% to >20% and kerogen types range from Type I to Type III. The organic matter can be of land plant, algal or bacterial origin. Most undegraded lacustrine oils are extremely paraffinic and waxy, but a few are asphaltic and rich in sulphur. The crude oils and source rocks contain a wide diversity of biological marker compounds reflecting different source inputs. The diversity of chemistries displayed by lacustrine source rocks and crude oils reflect the wide variety of organic source materials and depositional conditions operative in lakes.Lacustrine sequences preserved in the geological record represent sediments deposited in fluvial lakes on humid flood plains and tectonic lakes in humid, semi-arid and arid environments. Preservation of organic matter in lakes is dependent on the formation of anoxic or micro-oxic bottom waters. This is favoured by stratification of lake waters brought about by temperature and salinity contrasts. Organic material preserved in oligotrophic lakes is largely of land plant origin which has been extensively modified by bacteria under mildly oxidizing conditions and supplemented by the bacterial remains. Source rocks of this type are found in: (1) fluvial - lacustrine settings (e.g. Jurassic of Eromanga Basin, Australia) and (2) the oligotrophic phase of larger tectonic lakes (e.g. early stages of Green River Formation, Uinta Basin USA). As these freshwater lakes become productive, algal remains are contributed to the sediment and anoxic bottom waters can become more firmly established. The green algae Pediastrum and Botryococcus appear to be particularly important although land plant detritus is still significant (e.g. Cretaceous source rocks, Songliao Basin, China). Saline lakes conditions tend to restrict the diversity of the source biota although preservation may be enhanced through anoxia brought about by salinity stratification and inhibition of bacterial decay (e.g. later stages Green River Formation Uinta Basin, USA). Sulphate-rich, and hypersaline lacustrine systems result in the formation of sulphur-rich sources and oils (e.g. Jianghan Basin, China).Because of the diversity of organic matter types, maturation criteria for hydrocarbon generation in lacustrine sequences also vary. However in most cases, higher maturation levels are required for significant hydrocarbon generation. At present, it is uncertain the extent to which algal and bacterial organic matter contribute to the source for the waxy hydrocarbons which are characteristic of lacustrine oils. Organic-rich rocks formed in large freshwater and saline lakes are the most productive type of lacustrine source rock, although sources formed in lakes of flood plains and deltas are also widespread.     

Influence of refractory organic matter on source rock hydrocarbon potential: A case study from the Second White Specks and Belle Fourche formations,Alberta, Canada

Dilution by inert, refractory organic carbon can have a significant impact on the hydrocarbon potential of source rocks. In this study, a correction of total organic carbon, based on petrographic observations, is proposed to give a better indication of hydrocarbon generation potential. This correction shows that although the Second White Specks Formation is an excellent hydrocarbon source rock, hydrogen index and total organic carbon are influenced by dilution from refractory organic carbon of various sources. The results show that a higher degree of dilution occurs within the Belle Fourche Formation than the Second White Specks Formation. This dilution can have a significant impact on the hydrocarbon potential of the rock.Volumetric calculation of the inert carbon fraction using organic petrographic methods provides a semi quantitative method to correct total organic carbon values for the refractory organic carbon dilution effect. Incorporation of the dilution corrected organic carbon value in hydrogen index calculations allows a greater understanding of source rock hydrocarbon potential. This method provides better differentiation of the small scale variation between micro-facies and formation, as observed in the Second White Specks and Belle Fourche formations, than traditional bulk geochemical methodologies and previously proposed correction methodologies. Degree of dilution, either through transport of recycled allochthonous or autochthonous reworking of organic matter in-situ is highly variable and represents a significant challenge in the characterization of heterogeneous source rocks.This study investigates the organic petrology and geochemistry of a sediment core from the thermally immature area of the Upper Cretaceous Second White Specks Formation and Belle Fourche Formation. Reflectance and relative abundance of three maceral groups (bituminite, alginite, and refractory organic carbon macerals) showed significant organic matter compositional differences between micro-facies in the Second White Specks Formation. A change is also observed in organic matter composition from the upper part of the Belle Fourche Formation to the Second White Specks Formation. These compositional changes represent shifts in sediment source, sea floor oxygen levels, and depositional energy levels. These changes can be episodic, as observed between micro-facies, or longer time scale trends, as observed between the studied formations.     

东海西湖凹陷浙东中央背斜带烃源岩生排烃史研究

为了深化西湖凹陷浙东中央背斜带油气成藏过程的研究，优化勘探目标选择，在烃源岩特征分析的基础上，应用动态数值模拟技术，定量恢复了研究区主要烃源岩层系的生排烃历史，研究表明，浙东中央背斜带主要发育4套烃源岩系，其中始新统平湖组泥岩与煤层为主力烃源岩，具较高的有机质丰度=生烃强度与排烃效率，烃类排出具阶段性、多期次幕式排烃的特点汉平湖组为源岩的油气系统应是本区油气勘探的主要目标。     

西湖凹陷中-下始新统宝石组油气地质与勘探潜力

西湖凹陷是东海陆架盆地油气勘探潜力最好的凹陷之一。通过西湖凹陷宝石一井中下始新统宝石组井震资料,厘定了影响油气资源计算结果较大的关键参数,如烃源岩厚度、有机质油气产率、排聚系数等;建立了构造、沉积、孔隙度与油气生、运、聚模型,编绘了西湖凹陷宝石组生油岩厚度图、有机碳、Ro、生油气强度等值线图;采用BASIMS 4．5盆地综合模拟系统重现了西湖凹陷宝石组的地史、热史、生烃史、排烃史和运聚史,分析了宝石组空间展布特征与生、储、盖、圈、运、保等地质条件,提出并建立了宝石组合油气系统。利用多种方法定量计算的宝石组生烃量和资源量与西湖凹陷已证实的主力烃源岩系平湖组相似,认为宝石组是西湖凹陷又一重要烃源岩及油气勘探目的层系,拥有巨大的油气勘探潜力。     

Depositional environment of oil shale within the Eocene Jijuntun Formation in the Fushun Basin (NE China)

The non-marine Fushun Basin in NE China is a fault-controlled basin filled with Eocene sediments. It hosts the largest opencast coal and oil shale mine in Asia. A single thick oil shale layer overlying sub-bituminous coal occurs within the Middle Eocene Jijuntun Formation. Based on mineralogy, inorganic and organic geochemistry, organic petrography, stable isotope geochemistry, and vitrinite reflectance measurements, the depositional environment and the oil shale potential of the oil shale-bearing succession were investigated. The Jijuntun Formation is subdivided into a lower and an upper unit characterized by a low and high quality oil shale, respectively. The thick oil shale layer of the Jijuntun Formation developed under long-lasting stable conditions in a deep freshwater lake, after drowning of a swamp. The organic matter in the lower unit is characterized by landplant-derived macerals. The sediments containing a type II kerogen (HI: ∼400 mgHC/gTOC) were deposited during warm and humid conditions. Lacustrine organisms predominant in the upper unit are forming kerogen type I (HI: ∼700 mgHC/gTOC). High bioproductivity and excellent preservation conditions resulted in high TOC contents up to 23.6 wt.% in the upper unit. The organic matter preservation was controlled by photic zone anoxia originating in a temperature stratified water column in the deep lake, without significant changes in bottom water salinity. Mid-Eocene cooling during deposition of the upper unit of the Jijuntun Formation is reflected by clay mineral composition. A hot and arid climate favoring brackish conditions in a shallow lake prevailed during accumulation of the overlying carbonate-rich Xilutian Formation. Individual geochemical parameters in the Fushun Basin have to be used with caution, e.g. the maturity proxy T_max is affected by kerogen type, the redox proxy Pr/Ph ratio is probably biased by different sources of isoprenoids. This demonstrates the importance of multi-proxy studies.     

太湖五里湖沉降通量及其有机质分解率研究

为了进一步探索重富营养化湖泊水质形成机理,１９９６年７月１９日－９月２日,在太湖北端湖湾重富营养化水体－－五里湖中层水体进行了试验。通过对微分方程的积分与数理统计分析,确定了该湖区该时段平均沉降通量为４０５ｇｄ＾－１ｍ＾－２,其中有机质沉降通量是无机沉降通量的３倍,有机质初始分解率为０．０１２５１ｈ＾－１,长期分解率为０．００６６２ｈ＾－１,１个月的时间就有８０％的有机质分解掉。这种作用造成许多重     

北部湾盆地涠西南凹陷与海中凹陷古近纪沉积关系探讨

涠西南凹陷与海中凹陷相邻,油气勘探成果及石油地质条件认识程度不同。通过对地层原始产状的恢复,讨论了涠西南低凸起对两凹陷古近纪沉积环境的阻隔作用,并对古新世和始新世沉积可容空间原型进行了恢复,认为古新世两凹陷局部连通,始新世和渐新世两凹陷全部连通;3号断层作为两凹陷区划边界的一部分,其活动强度控制了沉积可容空间的分布和容积的大小,始新世3号断层活动强度最大,其形成的沉积可容空间也最大,由于两凹陷沉积连通,因此两凹陷始新统生烃能力可以进行类比分析。