地质条件下湖相烃源岩生排烃效率与模式

烃源岩排烃研究是油气地球化学研究中最薄弱的环节,而排烃效率又是准确评价常规油气与非常规页岩油气资源的关键参数。目前对于烃源岩排烃效率的认识差异很大,尚未建立完整的各种类型有机质湖相烃源岩在地质条件下生排烃效率与模式。本文以中国渤海湾、松辽等4个大型湖相含油气盆地以及酒泉青西凹陷、泌阳凹陷等9个中小型湖相富油盆地/断陷为对象,通过15000余个湖相烃源岩样品在自然热演化过程中热解生烃潜力指数的变化研究,揭示了湖相烃源岩在地质条件下的生排烃特征,构建了湖相烃源岩在地质条件下的生排烃效率与模型。无论是大型湖相沉积盆地还是中小型断陷盆地,甚至是盐湖相沉积盆地,烃源岩生排烃特征基本一致。随着成熟度的增高,湖相烃源岩排烃效率逐渐增高,在低成熟阶段排烃效率较低,在成熟与高成熟阶段具有高或很高的排烃效率。Ⅰ型、Ⅱ型有机质类型烃源岩排烃模式相似,相对排烃效率在低成熟阶段小于45%,成熟生油高峰时达85%~90%,至生油窗下限时达90%以上;累积排烃效率在低成熟阶段小于10%,生油高峰时达50%~60%,生油窗下限时达75%~85%,主要的排烃阶段在镜质组反射率0.7%~1.2%之间,生油窗阶段生成并排出了绝大部分烃类。湖相Ⅲ型有机质烃源岩排烃效率明显低于Ⅰ、Ⅱ型有机质烃源岩,生油窗阶段累积排烃效率仅为50%左右,主要生排烃阶段在镜质组反射率0.8%~2.0%之间。控制湖相烃源岩排烃量和排烃效率的主要因素是有机质丰度、类型和成熟度,而盆地类型、断裂发育程度、烃源岩沉积环境、相邻输导层孔渗条件等因素均不影响烃源岩排烃与排烃效率。     

雪峰山西侧震旦系陡山沱组烃源岩生烃潜力及油气地质意义

通过对雪峰山西侧地区震旦系陡山沱组烃源岩的系统观测、采样和有机地球化学研究总结了烃源岩分布规律、有机质母质类型,烃源岩的形成与沉积环境的关系、有机质成熟度及生烃史.陡山沱组黑色页岩分布及有机炭含量变化与陡山沱台盆相间的沉积模式有较大关系,陡山沱烃源岩主要分布于黔北、黔东等及上扬子东南缘等地区,黔北、黔东等地黑色页岩厚度20～70m,有机碳高值区(2.0％以上)主要分布在黔北、黔东及上扬子东南缘如石门—桃源—安化等地.有机显微组成分析表明该地区陡山沱组黑色页岩有机质类型为Ⅰ型,族组成质量分数均有饱和烃＞非烃＞芳烃的特点,盆地和斜坡相饱/芳一般要高于局限台地,不仅反映陡山沱组黑色岩系为腐泥型生油岩,而且反映陡山沱组沉积时期各地沉积母质类型与沉积环境具有一定的关系.陡山沱组不同地区沉积环境干酪根δ13Corg值不仅表明海洋浮游生物、海洋性自养菌及海生藻类为主的有机质来源在各地种类及丰度差别较大,对于特定生源(海生藻类、海洋浮游生物或海洋性自养菌)沉积有机质,沉积水体越深干酪根δ 13Corg一般越低,沉积形成的烃源岩有机质含量越高,表明烃源岩有机质含量是由有机质生产力、沉积母质类型和沉积环境共同决定.等效镜质体反射率为1.78％～3.05％,甲基菲指数MPI1值计算遵义松林陡山沱组有机成熟度Rc为1.96％,湄潭梅子湾Rc为2.06％～2.10％,反映大部分样品达到过成熟阶段,少量处于高成熟湿气阶段.生烃史模拟结果表明张家界地区陡山沱组烃源岩早志留世晚期(434Ma)进入生油阶段,中三叠世早期(244Ma)到达生油高峰并于中三叠世晚期Ro(％)达到1.3进入凝析油及湿气阶段,该结果反映陡山沱组烃源岩沉积背景为裂谷盆地晚期,古地温梯度较高生油门限深度较低,生油时间较早,有利于震旦系灯影组油气早期成藏.     

中国断陷盆地主要生油岩中的火山活动及其意义

通过对断陷盆地主力生油岩中普遍存在的基碱性火山岩的分析,认为水下火山喷溢环境是优质生油岩赖以形成的主导因素。岩浆、火山的高温无机气液具有加温、加氢、催化作用,是生油岩有机质在浅埋藏的低成熟阶段形成油气的主要动力。这种沉积有机质在火山作用下形成的油气称为有机一无机混合成因的油气。重视油源岩系的火山活动研究,发展多源成烃学说,可以开拓油气勘探新领域。     

玛湖凹陷风城组烃源岩特征与生烃模式

基于最新油气勘探成果及烃源岩有机地化分析数据和热模拟实验结果，评价了准噶尔盆地玛湖凹陷下二叠统风城组烃源岩的生烃能力，并进一步建立其生烃模式。研究区风城组发育一套沉积环境、岩性复杂多变的碱性湖泊相烃源岩，沉积水体盐度、碱度及成岩环境等变化快，致使源岩岩性复杂多变。其残余有机质丰度不高，类型为Ⅰ—Ⅱ型，大部分处于成熟阶段，热演化进程较慢。该组三个地层段均发育中—好烃源岩，少部分为很好烃源岩。风城组碱性湖泊相源岩生烃能力、模式与正常湖相源岩基本一致，为单峰式生油高峰，但其特点为生油持续时间长、总产油率远高于产气率、转化率高，主体处于生油阶段。油气勘探实践也证实玛湖凹陷是以含油为主的油气系统，在浅层或深层均以形成油藏为主。     

中口子盆地侏罗系煤系烃源岩地球化学特征及生烃潜力评价

甘肃-内蒙古交界处的北山盆地群侏罗系是我国西北地区潜在的油气勘探新领域。为加深对该盆地群资源潜力的认识,以有机地球化学分析数据为基础,探讨了其中煤系烃源岩的沉积环境、有机质来源,建立了该烃源岩生烃潜力评价标准。研究结果表明,中口子盆地侏罗系烃源岩干酪根类型以Ⅱ₁-Ⅱ₂型为主,生烃母质主要是陆生植物,含少量的藻类和水生生物,主要形成于三角洲平原沼泽或湖侵期的间湾湖泊等氧气量适中的弱氧化-弱还原沉积环境。生烃潜量和氢指数是衡量煤系源岩有机质丰度、生烃潜力和生油潜力最有效的指标,根据生烃潜力评价标准：黑帐房凹陷侏罗系暗色泥岩多属于中-差烃源岩,南泉凹陷暗色泥岩生烃潜力级别优于黑帐房凹陷,主要为中-好烃源岩;南泉凹陷炭质泥岩大多数属于中等-好油源岩,煤岩大多属于差油源岩。     

松辽盆地石炭-二叠系烃源岩研究

松辽盆地石炭-二叠系是烃源岩，沉积埋藏史可划分出持续深埋型、平衡埋藏型和短暂浅埋型3种类型。早白垩世晚期，石炭—二叠系烃源岩地温又一次达到并超过90℃，开始第二期生烃，油、气并生。这一时期，有效供烃区位于盆地东南部农安地区、西北部黑鱼泡地区，生气强度超过了生油强度。通过对石炭—二叠系沉积埋藏史、有机质热演化史和生烃史研究，无论对于深层找气，还是对盆地中新生代地层的油气勘探都具有十分重要的地质意义。     

鸡西盆地早白垩世烃源岩沉积有机相划分和评价

鸡西盆地早白垩世烃源岩的岩石类型是湖相泥岩、碳质泥岩和煤。根据其有机岩石学、沉积学和有机地球化学的特征,将该区沉积有机相划分为3种类型：高位沼泽有机相、滨浅湖-沼泽有机相和半深湖-深湖有机相。其中滨浅湖-沼泽有机相分布面积广泛,是最重要的生烃相带,有机质以Ⅲ型为主,生烃性能变化大,既可生油又可生气;半深湖-深湖有机相有机质为Ⅱ型,部分Ⅲ型,生烃性能良好并以生油为主,但分布面积局限;高位沼泽有机相由于处于盆地边缘,对生烃贡献不大。     

塔里木盆地奥陶系海相烃源岩中两类生烃母质（摘要）

对塔里木奥陶系海相烃源岩生烃母质的已有认识，一方面，普遍认为奥陶系烃源岩生源单调，均为富氢的菌藻类；另一方面，国外许多学者认识到全球范围内奥陶系烃源岩及生成原油特征上的相似性，他们认为这与粘球形藻(GloeocapsamorPha Prisca)作为主要生油母质有关。塔里木盆地中一上奥陶统台缘斜坡灰泥丘相生油岩由于有机质的双重来源，不同于国外奥陶系典型的Kukersite型生油岩(有机质主要来源于粘球形藻)。     

西藏南羌塘坳陷泥质烃源岩评价及有利生烃区预测

羌塘盆地是中国特提斯域面积最大、最具有含油气远景的沉积盆地，盆地内沉积有多套泥质烃源岩层，其中上三叠统土门格拉组、中—下侏罗统曲色—色哇组以及上侏罗统安多组三个层段生烃潜力巨大。本文在充分收集前人资料基础上，通过有机地球化学分析对南羌塘坳陷中生界上述三套泥质烃源岩层进行了综合评价研究，并对它们的生烃有利区进行了预测，探讨了优质烃源岩形成的主控因素。结果显示土门格拉组烃源岩有机质丰度中等偏低，有机质类型主为Ⅱ型，热演化程度较高，整体为差—中等生油岩，主力生烃坳陷位于分布在双湖多普勒乃—查郎拉和安多达卓玛—土门一带；曲色—色哇组有机质类型较好（Ⅱ1型），但有机质丰度偏低，且处于高成熟—过成熟阶段，属差生油岩，有利生烃区主要位于西部昂达尔错、中部扎曲乡和东部达玛尔地区，同时在双湖毕洛错地区发育一个相对局限的优质烃源岩区；安多组有机质丰度高，且有机质类型好（Ⅱ1型），处于生油高峰的成熟阶段，为好生油岩，但分布局限，主要位于安多114道班地区。沉积环境是南羌塘坳陷优质泥质烃源岩形成的主控因素：土门格拉组时期，温暖、潮湿的气候条件以及海—陆过渡环境相对较高的沉积速率，为该套优质泥质烃源岩的形成提供了条件；对于曲色—色哇组，广海边缘外陆棚体系不利于有机碳的沉积和埋藏，而相对局限的障壁—潟湖沉积环境则是优质烃源岩的有利形成区；上侏罗统安多组深水台沟相低能、静水的还原环境，以及浅水区稳定的有机质供给促进了该区富有机质黑色岩系的形成。这些研究对进一步明确羌塘盆地主力烃源岩特征与分布及下一步油气勘探具有重要参考价值。     

塔里木盆地奥陶系烃源岩二次生烃研究

为研究海相烃源岩二次生烃规律和塔里木盆地生排烃规律,以塔里木盆地奥陶系烃源岩为研究对象,首先通过构造-热演化史和生烃史研究得出,塔里木盆地典型构造单元奥陶系烃源岩具有二次生烃的特征,并且起始成熟度和生烃期次不同。然后选取自然条件下演化至不同起始成熟度的奥陶系海相烃源岩,采用热压模拟实验方法系统研究其二次生烃规律。研究表明：塔里木盆地奥陶系海相烃源岩二次生烃的主控因素是起始成熟度,二次生烃产率随起始成熟度增加规律性减小;低成熟和中成熟烃源岩具有大量生排油气潜力,出现相对延迟的生油高峰,高成熟烃源岩没有大量生油和生气的能力;两次不连续生烃量与一次连续生烃量的差值也受起始成熟度控制,具有阶段性;起始成熟度在低成熟到成熟阶段时,二次不连续生烃过程会增加烃源岩的生烃量,使生烃潜力增加,而高成熟阶段以后,二次不连续生烃过程就会减少烃源岩的生烃量,使生烃潜力减小。     

沉积盆地深部流体的地球化学特征及油气成藏效应初探

以济阳坳陷东营凹陷和塔里木盆地塔中地区为例，在前人深部流体研究的基础上，应用同位素地球化学、有机地球化学及热力学定量模型，对沉积盆地深部流体的活动特征及其油气成藏效应进行了初步的探讨。研究表明，在东营凹陷不仅存在着幔源富二氧化碳流体（H2O＋CO2）的活动，而且还存在着幔源富氢流体（H2O＋CH4＋H2）的活动。塔里木盆地塔中地区也发现了幔源富二氧化碳的活动。深部流体上升过程中热能传递的定量研究表明，幔源流体是良好的热能载体。东营凹陷和塔中地区的有机质异常热变现象证实了深部流体的热效应。有机质热演化生烃不仅需要热，而且是个缺氢的过程，富氢流体注入沉积盆地势必对油气的生成产生影响。加氢热模拟实验结果表明，加氢可大幅度提高烃源岩的产烃率；对腐泥型干酪根而言，加氢生烃效应最显著的阶段是在生烃高峰之后，产率可增加147％以上；腐植型干酪根的加氢生烃效应在各个阶段都较显著。在东营凹陷和塔中地区分别发现了深部流体促进烃源岩生烃的现象。因此，深部流体在能量上和物质上对油气的生成均可构成重要的影响。     

海相烃源岩二次生烃潜力定量评价新方法

烃源岩二次生烃的演化过程是残余干酪根热解演化与残留油热裂解转化两个既相互联系又完全不同的物理化学反应过程的叠加。本文利用自制高压釜热压生烃模拟实验装置,采取分阶段连续递进模拟实验方式,以海相烃源岩样品为例分别评价了残余干酪根的生烃潜力与残留可溶有机质转化油气潜力,建立了一套不同起始与终止成熟度海相烃源岩二次生烃潜力的定量评价方法,并首次明确提出了干酪根生油指数KIo、干酪根生气指数KIg、干酪根生烃指数KIh等评价烃源岩生烃潜力的参数,弥补了ROCK EVAL热解评价方法无法分别评价烃源岩在不同生烃演化阶段所生成的“油”或“烃气”潜力的不足。     

沉积盆地深部流体活动及油气成藏效应

沉积盆地深部流体包括幔源深部流体和壳源岩浆等,它们对成矿和油气成藏具有广泛而明显的影响。深部流体的油气成藏效应主要表现在四个方面:(1)形成与深部流体活动有关的无机成因气藏;(2)通过物质和能量交换,参与烃源岩的干酪根热解生烃;(3)通过溶蚀或交代,改变储层的岩石成分或孔渗结构进而改善其储集性能;(4)通过增温,驱动油气快速运移。论述了沉积盆地深部流体对油气成藏效应的研究进展及对油气勘探的重要意义。     

湖相富有机质泥质白云岩生排烃模拟及其对页岩油勘探的启示

富有机质湖相白云质泥岩、泥质白云岩及其贫有机质粉砂岩、白云岩夹层是我国陆相盆地页岩油勘探的重要领域,但目前针对湖相富有机质白云质泥岩或泥质白云岩在近地质条件下的生排烃一体化模拟研究尚属空白.以典型低熟富有机质泥质白云岩为例,开展了近地质条件下的生排烃一体化模拟实验,揭示了其呈现四阶段生排烃演化模式.结果表明,R_o ≤ 0.74%时为缓慢生油伴生烃气、排油能力有限阶段,0.74% < R_o ≤ 0.84%时为快速生油伴生烃气、排油能力逐渐增高阶段,0.84% < R_o ≤ 1.28%≈1.30%时为生烃气伴生油与油初始裂解、高效排油阶段,1.30% < R_o ≤ 2.00%时为油裂解烃气兼干酪根生烃气阶段;同时,R_o < 0.68%时滞留油主要以有机质吸附态赋存,而0.68% ≤ R_o ≤ 2.00%时滞留油主要以游离态赋存于矿物基质微-纳米级孔缝系统内.综合分析提出湖相泥质白云岩烃源层系有利页岩油勘探的成熟度范围为0.84%~1.30%.      

中国双相沉积盆地、古老结晶基底与东北地区深层潜在油气藏

基于我国双相沉积盆地与东北地域深部岩性地层潜在油气的必然前景,故必须把握全区沉积建造、结晶基底的起伏,火山岩分布和油、气盆地在浅部与深部不同岩相的空间展布;特别要在新的理念导向下,突破已有框架,重新进行油气远景的剖析和区划,深化认识油气形成和储集空间展布的深层动力过程.为此,揭示不同构造地域"透明"沉积建造、古老结晶基底和壳、幔深层动力学响应,必将成为我国在深部发现大型和超大型潜在油气藏的关键所在.通过国内外油气能源分布状况的研究指出,中国在多元共享世界能源的同时,必须立足于本土并强化安全、可靠与可持续供给的能源战略后备基地的建设.在剖析和研究我国沉积盆地中油气储层、沉积建造和结晶基底的基点上发现,在沉积盆地地域陆相地层下面仍普遍存在着海相地层,即盆地应为双相沉积盆地(陆相 海相);基底不应专指中、新生代沉积地层的底部,而应为古老的变质岩基底,即结晶地壳的顶部.基于这样的理念和对几个双相沉积盆地层序实例的分析提出:我国油气能源勘探在深部尚具有广阔的空间;在我国东北地域应全面进行双相沉积建造、火山岩分布、古老结晶基底的高精度探查;油气和沉积盆地形成的深层过程、动力学响应乃东北大庆、吉林等油气田及深部和周边地域发现新的油气藏、大幅度提升油气藏深部潜在空间的必须.基于双相沉积盆地和古老变质岩基底的研究,对在东北地域查明双相沉积建造、古老结晶基底、火山岩分布和第二深度空间(5 000～10 000 m)油气藏地球物理勘探与整体规划提出了布署和建议.     

Secondary hydrocarbon generation potential from heavy oil, oil sand and solid bitumen during the artificial maturation

Secondary hydrocarbon generation potentials from natural bitumen, oil sand and heavy oil, representing different residual oil accumulations, were determined by artificial maturation in a closed pyrolysis system. Simulated results indicate that their thermal behavior and reactivity are similar to those of kerogen, and that they can generate hydrocarbons once subjected to suitable geological processes. Overall differences in oil and gas generation potentials among the samples result from differences in the chemical structure of precursor components, physical compaction status, and mineral matrices. Hydrogen rich precursors, such as oil sand and heavy oil, have greater potential to generate hydrocarbons than hydrogen poor ones. Naturally compacted oil sand has slightly higher conversion efficiency than artificially compacted heavy oil as indicated by lower residual bitumen content. However, total gas and liquid oil recovery from oil sand is lower than from heavy oil due to the poor release of pyrolytic products from well compacted and cemented networks in the experiments. Mineral matrices of previous oil deposits also affect further hydrocarbon generation potential. Carbonate matrices inhibit total oil and gas generation, which consequently retains high gas potential at the postmature stage. Traditional oil generation models mainly consider the thermal alteration of kerogen; this study provides supplemental information for superimposed basins where previous oil accumulations may have been destroyed and reburied to serve as secondary sources of oil and gas. Consideration of previous oil residues as potential source rock allows better estimates of available oil resources and the risks associated with their exploration.     

深部流体中氢的油气成藏效应初探

深部流体对含油气盆地内油气成藏的影响已不断得到认识 ,人们在越来越多的油气田中发现了深部流体参与油气成藏的证据。氢是深部流体中重要的还原组分 ,许多沉积盆地都有氢异常的报道。深部来源的氢至少可能通过两种途径进入沉积盆地内 :一种是地球深部的氢直接通过深部脱气进入沉积盆地 ,通道为切穿盆地基底的深大断裂或伴随的火山活动 ;另一种来源是超基性岩的次生蚀变 ,如橄榄岩的蛇纹石化也可以放出氢。氢与沉积盆地内的有机质发生作用将会大大提高烃类的产率。加氢反应和合成反应是两种不同的机制。模拟实验表明在沉积盆地中存在加氢反应的条件 ,加氢反应可能是含油气盆地中广泛存在的一种生烃机制。在中国东部地区裂谷型盆地广泛地分布 ,并具有众多切穿基底的深大断裂 ,研究证实存在相当多的无机成因天然气 ,这预示着研究深部流体中氢的成藏效应不仅具有理论意义 ,而且也具有重要的现实意义。     

Differences in the Tectonic Evolution of Basins in the Central‐Southern South China Sea and their Hydrocarbon Accumulation Conditions

To reveal the causes of differences in the hydrocarbon accumulation in continental marginal basins in the centralsouthern South China Sea,we used gravity-magnetic,seismic,drilling,and outcrop data to investigate the tectonic histories of the basins and explore how these tectonic events controlled the hydrocarbon accumulation conditions in these basins.During the subduction of the Cenozoic proto-South China Sea and the expansion of the new South China Sea,the continental margin basins in the central-southern South China Sea could be classified as one of three types of epicontinental basins:southern extensional-foreland basins,western extensional-strike slip basins,and central extensional-drift basins.Because these basins have different tectonic and sedimentary histories,they also differ in their accumulated hydrocarbon resources.During the Cenozoic,the basin groups in the southern South China Sea generally progressed through three stages:faulting and subsidence from the late Eocene to the early Miocene,inversion and uplift in the middle Miocene,and subsidence since the late Miocene.Hydrocarbon source rocks with marine-continental transitional facies dominated byⅡ-Ⅲkerogen largely developed in extremely thick Miocene sedimentary series with the filling characteristics being mainly deep-water deposits in the early stage and shallow water deposits in the late stage.With well-developed sandstone and carbonate reservoirs,this stratum has a strong hydrocarbon generation potential.During the Cenozoic,the basin groups in the western South China Sea also progressed through the three developmental stages discussed previously.Hydrocarbon source rocks with lacustrine facies,marine-continental transitional facies,and terrigenous marine facies dominated byⅡ2-Ⅲkerogen largely developed in the relatively thick stratum with the filling characteristics being mainly lacustrine deposits in the early stage and marine deposits in the late stage.As a reservoir comprised of self-generated and self-stored sandstone,this unit also has a high hydrocarbon generation potential.Throughout those same three developmental stages,the basin groups in the central South China Sea generated hydrocarbon source rocks with terrigenous marine facies dominated byⅢkerogen that have developed in a stratum with medium thicknesses with the filling characteristics being mainly sandstone in the early stage and carbonate in the late stage.This reservoir,which is dominated by lower-generation and upper-storage carbonate rocks,also has a high hydrocarbon generation potential.     

The effect of oil expulsion or retention on further thermal degradation of kerogen at the high maturity stage: A pyrolysis study of type II kerogen from Pingliang shale,China

High maturity oil and gas are usually generated after primary oil expulsion from source rocks, especially from oil prone type I/II kerogen. However, the detailed impacts of oil expulsion, or retention in source rock on further thermal degradation of kerogen at the high maturity stage remain unknown. In the present study, we collected an Ordovician Pingliang shale sample containing type II kerogen. The kerogens, which had previously generated and expelled oil and those which had not, were prepared and pyrolyzed in a closed system, to observe oil expulsion or oil retention effects on later oil and gas generation from kerogen. The results show that oil expulsion and retention strongly impacts on further oil and gas generation in terms of both the amount and composition in the high maturity stage. Gas production will be reduced by 50% when the expulsion coefficient reaches 58%, and gas from oil-expelled kerogen (less oil retained) is much drier than that from fresh kerogen. The oil expulsion also causes n-alkanes and gas compounds to have heavier carbon isotopic compositions at high maturity stages. The enrichment of ¹³C in n-alkanes and gas hydrocarbons are 1‰ and 4–6‰ respectively, compared to fresh kerogen. Oil expulsion may act as open system opposite to the oil retention that influences the data pattern in crossplots of δ¹³C₂–δ¹³C₃ versus C₂/C₃, δ¹³C₂–δ¹³C₃ versus δ¹³C₁ and δ¹³C₁–δ¹³C₂ versus ln(C₁/C₂), which are widely used for identification of gas from kerogen cracking or oil cracking. These results suggest that the reserve estimation and gas/source correlation in deep burial basins should consider the proportion of oil retention to oil expulsion the source rocks have experienced.     

Research Progress in the Petroleum and Natural Gas Geological Theory of China

The Chinese landmass, as a composite region, consists of multiple small continental blocks, such as Sino-Korea, Yangtze, Tarim, etc., and orogenic belts. Because of its distinctive tectonosedimentary evolution, China’s oil/gas-bearing regions differ remarkably from that elsewhere in the world. For instance, in comparison to the Middle East oil/gas-bearing regions which are characterized by Mesozoic-Cenozoic marine oil/gas-bearing beds, early oil and gas discoveries in China are distributed mainly in Mesozoic-Cenozoic continental sedimentary basins. Generation of oil from terrestrial organic matter, or terrestrial oil generation, and the formation of large oil/gas fields in continental sedimentary basins were previously the major characteristics of petroleum geology of China. However, in the past 20 years, a series of major oil and gas discoveries from marine strata have been made. Marine oil/gas fields in China are mainly distributed in the Tarim, Sichuan, and Ordos basins, which are tectonically stable and covered with Mesozoic-Cenozoic deposits. In these basins, hydrocarbon-bearing strata are of old age and the oil/gas fields are commonly deeply-buried. Cumulatively, 995 oil/gas fields have been found so far, making China the fourth largest oil-producing country and the sixth largest gas-producing country in the world. In terms of petroleum and natural gas geology, theories of hydrocarbon generation from continental strata, such as terrestrial oil generation and coal-generated hydrocarbons, etc., have been established. Significant progress has been made in research on the sequence stratigraphy of continental strata, formation mechanisms of ultra-deep clastic reservoirs, and hydrocarbon accumulation in the continental subtle reservoir. Regarding research on the marine petroleum geology of China, with respect to the major characteristics, such as deeply-buried reservoirs, old strata, and multiple phases of transformation, important advances have been made, in areas such as the multiple-elements of hydrocarbon supply, formation of reservoirs jointly controlled by deposition, tectonic activities, and diagenetic fluid-rock reactions, and oil/gas reservoirs formed through superimposed multi-stage hydrocarbon accumulation. As more and more unconventional hydrocarbon resources are discovered, unconventional oil and gas reservoirs are under study by Chinese petroleum geologists, who endeavor to come up with new discoveries on their formation mechanisms.