鄂尔多斯盆地长6油层组深水沉积特征与致密油藏分布

为了拓宽勘探领域,预测有利砂体及油藏展布,指导下一步勘探部署,在大量岩心、野外露头观察的基础上,结合铸体薄片、图像粒度等分析化验手段,对鄂尔多斯盆地长6油层组深水沉积类型及致密油藏分布进行了系统研究。结果表明:长6油层组岩心中发育大量的深水沉积构造,包括有粒序层理、底部印模构造以及准同生变形构造等,据此将其划分为深水三角洲前缘、砂质碎屑流、浊流以及滑塌重力流等多种深水沉积类型。其中,分布于东北部的深水三角洲前缘砂体以及湖盆中部的砂质碎屑流砂体是区内的主要储集砂体,而西部和深水沉积中心的滑塌、浊积砂体为次要储集砂体。致密油藏在区内东北部大面积复合连片,而在西南部则以相对孤立的形式发育。     

加拿大东部斯科舍盆地塞布尔次盆下白垩统深水重力流沉积研究

针对加拿大东部斯科舍盆地重力流沉积演化研究不足的问题,综合岩心、测井、地震及磁异常等资料,明确斯科舍盆地塞布尔次盆下白垩统重力流沉积单元,揭示其沉积演化并探讨发育控制因素。研究结果表明：斯科舍盆地塞布尔次盆下白垩统密西沙加组和洛根峡谷组发育规模性重力流沉积,可以识别出块体搬运、重力流水道、天然堤及朵叶体等沉积单元;密西沙加组沉积初期（距今147 Ma）研究区西部发育小型重力流沉积,沉积末期（距今130Ma）研究区中部发育大型坡底扇;洛根峡谷组沉积初期（距今113 Ma）研究区普遍发育小型重力流沉积,沉积末期（距今101 Ma）研究区东南部发育大型坡底扇。陆架边缘三角洲进积及陆坡窄、陡,分别为重力流发育提供了物质基础和动力条件。     

从中国沉积盆地的结构看塔里木盆地找油方向

从勘探实践证明,一般箕状断陷发育的中期为其主导的成油期,多层结构的沉积盆地台型构造层是最佳成气期。塔里木盆地是典型的“台、断、拗”多层结构的含油气盆地,所以其台型构造层同样为最佳成气期(与四川、鄂尔多斯盆地所不同的是热流值较低致使凝析油比例较大),箕状断陷发育阶段也同样是最佳成油期。以这一地质规律为鉴,除目前重点勘探区外,应运用地震新方法(即同时加垂直反射主剖面测线的折射地震排列)相继开辟中生界一下第三系发育的库车、西南断陷的地震勘探工作,为下步找油工作准备出目的层准确的构造高点。     

沉积过程对莺歌海盆地烃源岩生气的控制作用

东方区与乐东区是莺歌海盆地2个主要天然气探区,2 个区中新统烃源岩有机质成熟度存在较大差异,表现为相同埋深时东方区有机质演化程度比乐东区高。在莺歌海盆地构造演化、温压场与烃源岩地球化学特征研究的基础上,通过沉积过程分析与盆地模拟相结合探讨有机质热演化差异的成因。研究认为：新近纪至第四纪盆地沉积沉降中心由东方区向乐东区迁移,导致二者在不同时期的沉积速率不同。尽管盆地的高温高压场对有机质热演化产生一定影响,但造成东方区与乐东区有机质热演化差异的主要原因是2个区不同的沉积速率。而有机质热演化差异造成了生气过程的差别：东方区生气时间早、持续时间长,而乐东区表现为晚期快速生气的特点,更有利于天然气的聚集成藏。乐东区中新统烃源岩生烃过程中有机酸的形成时间也较晚,有助于该储层次生孔隙的发育,因此乐东区成藏条件更优越,勘探前景良好。该成果不仅对莺歌海盆地天然气勘探具有重要的指导作用,同时对其他区域也具有较为广泛的借鉴作用。     

加蓬盆地深水盐下构造—沉积演化及其对油气成藏的影响

为了揭示加蓬盆地深水盐下油气成藏条件和成藏关键因素,有效指导油气勘探,在综合现有勘探研究成果的基础上,系统分析了深水盐下构造—沉积演化特征及其对油气成藏的影响。研究结果表明,加蓬盆地盐下经历了断陷期(早白垩世纽康姆期—巴列姆早期)、断拗期(巴列姆晚期—阿普特早期)和过渡早期(阿普特中期)3个构造—沉积演化阶段。断陷期控制了盐下烃源岩的发育。受区域南强北弱裂谷作用的影响,北加蓬次盆湖相烃源岩主要局限分布于内裂谷带;南加蓬次盆湖相烃源岩广泛分布。烃源岩的差异性分布是目前北加蓬次盆外裂谷带勘探失利而南加蓬次盆外裂谷带获得油气发现的主要原因。断拗期和过渡早期控制盐下主力储层的发育。受沉降中心向外裂谷迁移和构造沉降作用南强北弱的继承性影响,断拗期Dentale组在内裂谷带和中部隆起带广泛发育河流相沉积,而在南加蓬次盆深水区(外裂谷带)过渡为三角洲前缘—浅湖相沉积;过渡早期Gamba组沉积于准平原化背景之下,在内裂谷带和中部隆起带发育河流—三角洲平原沉积,而在外裂谷(现今深水区)过渡为以三角洲前缘—浅湖相沉积为主。二者均存在储层物性向深水区变差的风险。沿N’Komi断裂带发育的物源长距离输送通道,对外裂谷带深水区Dentale组和Gamba组储层发育具有十分重要的意义。     

车镇凹陷北部陡坡带断裂结构及其对沉积和成藏的控制

车镇凹陷北部陡坡带边界断裂长期活动，构造复杂，是扭张和拉张等多期构造应力共同作用的产物。根据边界断层几何学和运动学的差异，将车镇凹陷北部陡坡带的断裂结构分为简单和复式2类及板式、铲式、阶梯式和坡坪式4种。断裂结构对盆地的沉积充填样式、储层发育规模和油气藏类型具有较强的控制作用。研究结果表明，铲武断裂结构中发育的低位湖底扇或滑塌浊积扇以及坡坪式和阶梯式断裂结构中断阶潜山或滑脱潜山为最重要的勘探目标。     

国外致密油储层微观孔隙结构研究及其对鄂尔多斯盆地的启示

致密油储层微观孔隙结构是致密油储层研究的重点和难点,也是制约致密油勘探、开发的关键问题,主要表现在：致密油储层微观孔隙结构表征难、分类评价难、预测难,并且孔隙结构与油气赋存和渗流的关系复杂等。国外在致密油储层微观孔隙结构研究方面取得了一些进展：发现了纳米孔喉储集类型并研究了其成因;逐级深入,形成了微观尺度分析测试系列方法;发展了数字岩心技术;定量分析了矿物成分及其在微观渗流中的作用;有效识别和表征了微裂缝;对比分析了储层中各类孔隙及流体分子的尺度。根据国外的经验,探讨了鄂尔多斯盆地致密油储层微观孔隙结构研究的思路和方法,指出要在致密油储层微观孔隙结构测试手段上有所突砘要证实致密油储层中纳米级孔隙的存在与否及其贡执要揭示致密油储层中孔隙和喉道的配置关系;要认识致密油储层中微裂缝发育及分布规律;要探讨致密油储层改造及储层保护的手段．     

莺-琼盆地高温超压对有机质热演化的影响

剖析影响莺-琼盆地10口高温高压井的实测镜质体反射率数据的因素,结合热模拟实验结果,探讨高温、超压对第三系腐植型有机质热演化与生烃的影响。认为：高地热场为腐植型有机质向天然气转化提供了有利的条件,特别是莺歌海盆地泥底辟带存在短暂的深源热流体上侵,可能使浅层沉积中的有机质转化成低成熟原油;超高压对有机质热演化的抑制作用是次要的,即便有少许抑制作用,也往往被高温效应掩盖。图4表1参17     

鄂尔多斯盆地南缘长10—长9油层组沉积特征

鄂尔多斯盆地三叠系延长组是主要勘探目标之一。以鄂尔多斯盆地南缘露头剖面详细勘探为基础,结合前人成果,对岩性和岩石组合、沉积相特征及时空演化进行系统分析。结果表明:鄂尔多斯盆地南缘长10—长9油层组可划分9种岩相类型,发育曲流河、曲流河三角洲及辫状河三角洲3种沉积相,曲流河相发育河床滞留沉积、边滩、天然堤及决口扇4种微相,曲流河三角洲发育水下分流河道、水下天然堤、分流间湾、河口坝及远沙坝5种微相,辫状河三角洲发育水下分流河道、分流河道间2种微相;长10—长9油层组垂向上具有粗—细—粗的复合韵律特征;曲流河砂体、三角洲前缘砂体是油气运移聚集的主要场所。     

渤海湾盆地垦东凸起构造演化及对沉积的控制作用

为了深入研究垦东地区的构造特征与油气聚集规律,寻找有利的油气圈闭,讨论了垦东地区的构造演化史和垦东地区构造演化对沉积的控制作用.通过对本区地质、地球物理的综合研究,得出以下结论:构造发展史表明,垦东凸起及北部斜坡带经历了裂谷期前、裂谷期和裂谷期后三大发育阶段,纵向上呈三层结构分布;垦东凸起及邻区的沉积受构造演化影响明显...     

THERMAL MATURITY AND HYDROCARBON GENERATION IN ROCKS FROM THE SEDIMENTARY BASINS OF MADAGASCAR

Oil exploration in Madagascar has been concentrated on the Morondava Basin in the SW of the island, which is well-known for its large deposits of tar sand and heavy oil at Bemolanga and Tsimiroro. Petroleum shows have frequently been encountered in exploration wells, but source-rock identification has remained inconclusive. Thus, the present study of a wildcat was originally related mostly to geochemical prospect appraisal. Due to the uniform organic matter type and wide range of thermal evolution stages sampled, the case history has more general implications, however, as regards relationships between thermal maturation and hydrocarbon generation. Evaluation of eleven rock samples taken at depths of between 1,100 and 2,500m by Rock-Eval, solvent extraction and vitrinite reflectance (R_r) methods revealed only poor source rocks for oil with marginal through to post-mature Type III kerogens (R_r between 0.5% and 1.4%). Discrepancies in yield profiles of total C₁₅₊ -hydrocarbons peaking at higher R_r in the Morondava and Douala Basin (Cameroon) wells than in a Deep Basin (West Canada) well are tentatively attributed to their different geothermal histories. However, yield trends of specific saturated and aromatic hydrocarbon families, as determined by capillary gas chromatography, did not testify to the suspected effect of geothermal rate variations on generation curves, which hence remain unproven. Based on systematic changes with depth in the distribution of methylated di- and tri-aromatics, the interpretation of maturation levels with respect to hydrocarbon generation was refined. When converted to vitrinite reflectance equivalents (R_r), molecular parameters such as the Trimethylnaphthalene Ratio (TNR 1) and the Methylphenanthrene Index (MPI 1) were able to disclose gradual maturity changes. In contrast to the large Morondava Basin, the smaller Majunga Basin in NW Madagascar has been the site of little exploration activity until recently. Based on organic-geochemical analysis of seven rock samples from two exploration wells by the above-mentioned methods, it was found that good source rocks for oil are absent. Some of the samples may have a considerable gas generation potential, which at best has been partially realised. Certainly, maturities inadequate for substantial gas generation are indicated by aromatic parameters.     

THERMAL MATURITY AND HYDROCARBON GENERATION IN ROCKS FROM THE SEDIMENTARY BASINS OF MADAGASCAR

Oil exploration in Madagascar has been concentrated on the Morondava Basin in the SW of the island, which is well-known for its large deposits of tar sand and heavy oil at Bemolanga and Tsimiroro. Petroleum shows have frequently been encountered in exploration wells, but source-rock identification has remained inconclusive. Thus, the present study of a wildcat was originally related mostly to geochemical prospect appraisal. Due to the inform oraganic matter type and wide range of thermal evolution stages sampled, the case history has more general implications, however, as regards relationships between thermal maturation and hydrocarbon generation. Evaluation of eleven rock samples taken at depths of between 1,100 and 2,500m by Rock-Eval, solvent extraction and vitrinite reflectance (Rr) methods revealed only poor source rocks for oil with marginal through to post-mature Type III kerogens (Rr between 0.5% and 1.4%) Discrepancies in yield profiles of total C15+ -hydorcarbons peaking at higher R_r in the Morondava and Dauala Basin (Cameroon) wells than in a Deep Basin (West Canada) well are tentatively attributed to their different geothermal histories. However, yield trends of specific saturated and aromatic hydrocarbon families, as determined by capillary gas chromatography, did not testify to the suspected effect of geothermal rate variations on generation curves, which hence remain unproven. Based on systematic changes with depth in the distribution of methylated di- and tri-aromatics, the interpretration of maturation levels with respect to hydrocarbon generation was refined. When converted to vitrinite reflectance equivlents (Rc), molecular parameters such as the Trimithylnaphthalene Ration (TNR 1) and the Methylphenanthrene Index (MPI I) were able to disclose gradual marurity changes. In contrast to the large Morondava Basin, the smaller Majunga Basin in NW Madagascare has been the site of little explortion activity until recently. Based on organic-geochemical analysis of seven rock samples from two exploration wells by the above-mentioned methods, it was found that good source rocks for oil are absent. Some of the samples may have a considerable gas generation potential, which at best has been partially reasised. Certainly, maturities inadequate for substantial gas generation are indicated by aromatic parameters.     

盆地深部形成油气藏的有利因素

本文主要阐述了形成深部油气藏的三个因素:即Ⅰ型干酪根在高成熟阶段具有一定的生烃潜力;碳酸盐岩生油岩的成熟作用慢于泥岩生油岩,晶包有机质转化及释放烃类是在高成熟阶段,碳酸盐岩生油岩生油下限的R。值在1.5％以下,液态窗的深度比泥岩大500～1000m;较高的压力是形成深部油藏的另一个重要因素。生油岩的高压生烃模拟实验揭示了高压可以使生油期滞后及提高产油率。地温梯度较低的塔里木、准噶尔盆地腹部,由于压力较高,生油的下限可达7000m。在快速沉降的新生代盆地,由于泥岩快速生油而又难以排放,形成局部异常高压带。异常高压区生油的深度可以向下延伸1000多米,封隔层之下的高压区是深部形成大规模油气藏的广阔场所。     

陆源盆地的生油

本文重点讨论了陆生植物遗体作为石油生成的母源问题。以脂肪酸为例,阐明了成煤和成油的热力学过程,以及沉积物中各种有机物质碳、氢成分的演变和热解机理。最后,文中讨论了石油中各种陆源生物标记等问题。     

PETROLEUM POTENTIAL, THERMAL MATURITY AND THE OIL WINDOW OF OIL SHALES AND COALS IN CENOZOIC RIFT BASINS, CENTRAL AND NORTHERN THAILAND

Oil shales and coals occur in Cenozoic rift basins in central and northern Thailand. Thermally immature outcrops of these rocks may constitute analogues for source rocks which have generated oil in several of these rift basins. A total of 56 oil shale and coal samples were collected from eight different basins and analysed in detail in this study. The samples were analysed for their content of total organic carbon (TOC) and elemental composition. Source rock quality was determined by Rock‐Eval pyrolysis. Reflected light microscopy was used to analyse the organic matter (maceral) composition of the rocks, and the thermal maturity was determined by vitrinite reflectance (VR) measurements. In addition to the 56 samples, VR measurements were carried out in three wells from two oil‐producing basins and VR gradients were constructed. Rock‐Eval screening data from one of the wells is also presented. The oil shales were deposited in freshwater (to brackish) lakes with a high preservation potential (TOC contents up to 44.18 wt%). They contain abundant lamalginite and principally algal‐derived fluorescing amorphous organic matter followed by liptodetrinite and telalginite (Botryococcus‐type). Huminite may be present in subordinate amounts. The coals are completely dominated by huminite and were formed in freshwater mires. VR values from 0.38 to 0.47%R_o show that the exposed coals are thermally immature. VR values from the associated oil shales are suppressed by 0.11 to 0.28%R_o. The oil shales have H/C ratios >1.43, and Hydrogen Index (HI) values are generally >400 mg HC/g TOC and may reach 704 mg HC/ gTOC. In general, the coals have H/C ratios between about 0.80 and 0.90, and the HI values vary considerably from approximately 50 to 300 mg HC/gTOC. The HI_max of the coals, which represent the true source rock potential, range from ～160 to 310 mg HC/g TOC indicating a potential for oil/gas and oil generation. The steep VR curves from the oil‐producing basins reflect high geothermal gradients of ～62°C/km and ～92°C/km. The depth to the top oil window for the oil shales at a VR of ～0.70%R_o is determined to be between ～1100 m and 1800 m depending on the geothermal gradient. The kerogen composition of the oil shales and the high geothermal gradients result in narrow oil windows, possibly spanning only ～300 to 400 m in the warmest basins. The effective oil window of the coals is estimated to start from ～0.82 to 0.98%R_o and burial depths of ～1300 to 1400 m (～92°C/km) and ～2100 to 2300 m (～62°C/km) are necessary for efficient oil expulsion to occur.     

我国近海沉积盆地多重动力成因和油气聚集

近年来在深部和区域地质方面所获得的新的发现进一步支持了我国近海沉积盆地经历了多期热事件的认识。近海盆地的成因与深部作用地幔柱构造不可分割,表现出与亚洲东部特殊的地质背景的相关性和统一性。多幕动力作用决定了盆地具有多个含油气系统,其中超压系统多期破裂产生并驱动的含烃热流体的多期活动成藏和重就位是基本的成藏动力学特征。而现今作为含烃流体场动态演化的一个切面,油气藏是盆地流体场中的特殊异化点,因此盆地水文系统的温、压、化学场以及成岩场的特征是判别油气藏分布的重要标志。     

新疆三大沉积盆地油气藏形成与分布

新疆三大盆地油气生成、运移有四大高峰期,且与圈闭形成高峰期相对应,因而造就了盆地成藏的四大高峰期.那些在多期成藏过程中不断获得油气供给的圈闭,可形成大型油气藏.油气分布受大型隆起带、断裂背斜带与斜坡带的控制,形成隆起被覆背斜型、前陆掩冲带型与斜坡断阶带型三大复式油气聚集组合.     

新疆三大沉积盆地油气藏形成与分布

新疆三大盆地油气生成、运移有四大高峰期,且与圈闭形成高峰期相对应,因而造就了盆地成藏的四大高峰期.那些在多期成藏过程中不断获得油气供给的圈闭,可形成大型油气藏.油气分布受大型隆起带、断裂背斜带与斜坡带的控制,形成隆起被覆背斜型、前陆掩冲带型与斜坡断阶带型三大复式油气聚集组合.     

中国西北地区压性叠加盆地成油特征

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