基于钻井、地震、测井、测试以及实验分析等新资料，针对中西部叠合盆地深层—超深层海相碳酸盐岩层系成储、成藏和油气藏高效开发面临的关键科学问题开展持续攻关。研究表明：①断裂主导形成的储集体和古老层系白云岩储层是深层—超深层海相碳酸盐岩两类重要的储层；以断裂为主导形成的规模储集体，根据成因可进一步分为3种类型：断裂活动过程中构造破裂形成的缝洞储集体、致密碳酸盐岩受断裂和流体双重改造形成的储集体与早期丘滩等高能相带受断裂和流体改造形成的储层；优势丘滩相、早期白云石化和溶蚀、酸性流体环境、膏盐岩封盖和超压是优质白云岩储层形成和保持的关键。②中国中西部叠合盆地海相碳酸盐岩层系富有机质页岩主要发育于被动陆缘深水陆棚、碳酸盐缓坡等环境中，构造-热体制是控制深层—超深层油气藏赋存相态的重要因素，改造型动力场控制中西部叠合盆地深层—超深层海相碳酸盐岩油气成藏与分布。③普光等高含硫酸性气田开发过程中硫析出堵塞井筒，采用井筒溶硫剂配合连续油管解硫堵效果明显；基于沉积模拟的双重介质建模数模一体化技术可以精细刻画水侵前缘空间展布及变化，并据此提出气井全生命周期调、排、堵控水对策。④超深断控缝洞油气藏开发过程中，储层应力敏感，渗透率随压力下降而显著降低，产量递减较快；凝析气藏相态变化快，压降显著影响凝析油采出程度；据此提出“注水+注天然气”重力驱油藏开发方法和“高注低采”天然气驱凝析气藏开发方法；采用分层次约束、逐级地质建模和流-固-热耦合的复合介质数值模拟有效提高了油气藏开发生产动态模拟的预测精度。

以塔里木盆地海相碳酸盐岩层系为重点,研究烃源岩发育与油气藏之间的关系,探讨中国高热演化程度、低TOC值（小于0.5%）海相碳酸盐岩层系作为烃源岩的可能性及其生烃机理。通过对塔里木盆地烃源岩分布与塔河油田油气藏的匹配关系、烃源岩成烃生物组合及其与油气藏的地球化学特征对比分析,建立海相碳酸盐岩烃源岩成烃物质评价方法。研究得出塔里木盆地塔河油田原油并非来自泥质烃源岩,而具有来源于碳酸盐岩烃源岩的明显特征,进一步揭示高热演化碳酸盐岩中被低估的生烃物质（有机酸盐）及碳酸盐岩中优质成烃生物组合是高热演化碳酸盐岩可以作为烃源岩的关键,有机酸盐具有高温裂解成烃、主体成气和成烃转化率高的生烃特征。塔里木盆地寒武系—中下奥陶统有效碳酸盐岩烃源岩的发育模式以陆棚模式为主。图6表1参85

The marine carbonates of the Tarim Basin are taken to study the relationship between source rock and oil and gas reservoirs and discuss the possibility and mechanisms of mature and low-TOC (less than 0.5%) marine carbonates being source rock. By studying the matching relationship between source rocks in Tarim Basin and hydrocarbon reservoirs in Tahe oilfield and analyzing the hydrocarbon-generating organism combination and its correlation with geochemical characteristics of oil and gas reservoirs, this study established a method to evaluate hydrocarbon generation substance of marine carbonate source rocks. It is concluded that the crude oil of the Tahe oilfield in the Tarim Basin is not derived from muddy source rocks, but has the obvious characteristics derived from carbonate source rocks. It revealed that the underestimated hydrocarbon-generating substance (organic acid salts) in the highly evolved marine carbonate rocks and high quality hydrocarbon-generating organism are the key to high-evolution carbonate rocks being as source rock. Organic acid salts have high hydrocarbon conversion rate and are mainly cracked into natural gas at high temperature. The development model of the source rocks of the Cambrian-Lower Ordovician carbonate source rocks in the Tarim Basin is dominated by the shelf model.

近年来，在塔里木、四川、鄂尔多斯三大盆地海相碳酸盐岩层系中相继发现了一批以地层-岩性油气藏为主体的大油气田，虽然单个油气藏储量丰度低，但由于油气藏呈集群式分布，因此总体油气储量规模大。为了揭示海相碳酸盐岩大油气田形成条件和分布规律，本文从盆地的构造演化、烃源灶的分布范围、有效储层的发育条件以及油气成藏模式等方面，来分析和探讨中国三大克拉通盆地海相碳酸盐岩层系油气藏大型化成藏条件与特征。研究表明，大范围分布的烃源灶及其晚期规模生烃是大油气田形成的资源基础;大面积呈似层状分布的礁滩体及受不整合面控制的岩溶储集体为大油气田的形成提供了有效储集空间;“退火”地温场与递进埋深的耦合是大范围油气成藏的重要机制;下侵式、扬程式、转接式成藏模式是油气大范围成藏的重要途径。古隆起及其斜坡带、台缘带礁滩体、与蒸发岩共生的台内滩、深大断裂带具备形成碳酸盐岩大油气田地质条件，是油气勘探的有利区带。

In recent years, a series of large oil-gas fields dominated by stratigraphic-lithological reservoirs have been found in marine carbonate reservoirs in three large onshore basins in China, i.e., Tarim Basin, Sichuan Basin, and Ordos Basin. Despite low abundance of reserves in each of these oil-gas reservoirs, their overall scale is large due to cluster distribution. In order to reveal accumulation factors and distribution patterns of large-scale oil-gas fields in marine carbonate reservoirs, this study analyzed and discussed large-scale hydrocarbon accumulation factors and characteristics of marine carbonate reservoirs in the three large cratonic basins from four aspects: (1) tectonic evolution of cratonic basin; (2) distribution of hydrocarbon source kitchen; (3) development conditions of effective reservoirs; and (4) model of hydrocarbon accumulation. Results show that widely distributed hydrocarbon kitchens and their late large-scale accumulation are resource base of large oil-gas fields. A large area of reefs and shoals in stratoid distribution and karst reservoirs controlled by unconformity surface provide effective reservoir space for formation of large oil-gas fields. Coupling of annealing geothermal field and progressive burial is an important mechanism of large-scale hydrocarbon accumulation in marine carbonate reservoirs in the cratonic basins. Downward invasion model, lift model, and switching model are important pathways for petroleum accumulation. This study indicates that palaeouplifts and associated slope zones, reefs and shoals in platform margin zone, intra-platform shoals symbiotic with evaporites, and deep faults meet geological conditions for large-scale oil-gas field formation in carbonate reservoirs, and thus are favorable zones for oil-gas exploration.

含油气盆地深层系指埋深超过4 500 m的地层领域。截至2010年,全球已发现200个埋深超过4 500 m的含油气盆地,发现了1 477个深层油气藏。塔里木盆地在深层和超深层发现的石油天然气储量所占比率已从2000年的66 % 上升到2013年的92 %,勘探前景广阔。近20年来,在含油气盆地深层构造与地质环境、深层碎屑岩有效储层和碳酸盐岩有效储层、深层油气来源与评价方法、深层油气成藏与分布规律、深部油气相态特征与油气藏保存6个方面的研究取得了重要进展。目前深层油气勘探面临系列挑战,突破当前困局需要开展7个方面的研究,包括:提高深层资料品质、增加深层信息探测手段和数据处理技术、强化构造过程与温压场演化历史研究、开展储油气层演化动力学过程研究、加强油气地球化学与油气资源评价研究、揭示高温高压和低孔低渗等非常规条件下油气藏成因机制研究、建立深层油气地质学与深层油气勘探新理论并研发配套新技术。

Deep strata of petroliferous basin refer to the formations with the buried depth more than 4 500 m. Till 2010, a total of 200 petroliferous basins have been discovered with the buried depth more than 4 500 m in the whole world, as well as 1 477 deep hydrocarbon reservoirs. In Tarim Basin, the proportion of discovered deep and ultra-deep hydrocarbon reserves was increased from 66 % in 2 000 to 92 % in 2013, indicating a huge exploration prospect. Over the past two decades, important achievements have been made in research of the following six subjects, i.e., deep structure and geological environment of petroliferous basin, effective reservoirs of deep clastic and carbonate rocks, origin and assessment method of deep hydrocarbons, deep hydrocarbon accumulation and distribution laws, deep hydrocarbon phase characteristics and reservoir preservation. At present, the exploration of deep hydrocarbon is facing a series of challenges. The research on seven aspects should be carried out to break through the current dilemma, including the improvement in the quality of deep data, the increase in deep information detection methods and data processing technologies, the enhancement of study on tectonic process and the evolutionary history of pressure and temperature field, the research on the dynamic process of hydrocarbon reservoir evolution, the enhancement in the research of hydrocarbon geochemistry and resource assessment, the studies with the aim to reveal the genetic mechanism of hydrocarbon reservoir under high temperature and high pressure, low porosity-low permeability and other unconventional conditions, the establishment of new theories for deep hydrocarbon geology and exploration, as well as the development of new matching technologies.

Identification of natural gas genesis and source for high-matured multiple natural gases is a great challenge in the exploration of deep-ultra deep and unconventional natural gases. In this paper, the genesis identification method system of multiple natural gases is enriched through new experimental techniques and comprehensive analysis of geological data. New indexes and charts of genesis identification for multiple natural gases were determined to distinguish the sapropelic kerogen degraded gas and crude oil cracking gas, accumulated and scattered liquid hydrocarbon cracking gas in different evolution stages, nitrogen, carbon dioxide of organic and inorganic origins, inert gases of crustal and mantled origins, coal-formed gas and oil-type gas by helium, nitrogen, carbon dioxide and mercury content in natural gas. These indexes and charts have been successfully applied in the Sichuan, Tarim and Songliao basins to identify the natural gas genesis and source for complicated gas reservoirs. The research results have provided effective support for the natural gas exploration in the Sinian-Cambrian ancient carbonate formations in the Sichuan Basin, deep formations in the Kuqa depression of the Tarim Basin, and deep volcanic formations in the Songliao Basin.

通过对天然气碳同位素、氢同位素和干燥系数关系的分析,划分歧口凹陷的烷烃类天然气成因类型，拓展研究区天然气勘探领域，明确今后勘探方向。歧口凹陷的烷烃类天然气包括生物气、生物—热成因混合气和热成因气3个大类，热成因气是凹陷的主力天然气类型，其探明储量占总储量的95%以上。热成因气按母质类型又划分为陆相油型气和煤成气，油型气按成熟度分为低熟气、成熟气和高熟气，主要来自第三系湖相泥岩；埕海潜山天然气属于高熟煤成气，主要来自石炭系—二叠系煤系烃源岩。今后，歧口凹陷天然气勘探应坚持以中深层为主要层段，以潜山和深层碎屑岩为主要勘探领域，同时加强煤成气资源潜力的研究。

Genetic types of hydrocarbon gases of Qikou sag are divided according to the relationships among carbon isotope,hydrogen isotope and dry coefficient.This study has extended gas exploration field of the study area,makes the future exploration direction clear.Hydrocarbon gases in Qikou sag are divided into three types,which are biogenic gas,mixture of biogenic and thermogenic gas,and thermogenic gas.Thermogenic gas is the main gas type in Qikou sag,with its proven natural gas reserves more than 95% of the total.Thermogenic gas can be further divided into continental oil-type gas and coal type gas.Oil-type gas,including low mature gas,mature gas and high mature gas,mainly comes from Tertiary lacustrine mudstone.Gas in buried hill of Chenghai is coal-high mature gas,which mainly comes from Permo-Carboniferous coal-measure source rocks.Further natural gas exploration in Qikou sag should mainly focus on the middle-deep layers in exploration sections and the buried hill and deep clastic reservoir in exploration fields.And besides,research on coal-formed gas resource potential should be strengthened.

以地震、钻井和实验分析为基础,对塔里木盆地古城地区奥陶系鹰山组三段滩相白云岩气藏特征及成藏主控因素进行研究。结果表明,古城地区白云岩气藏类型为“滩-断双控”的岩性气藏,其形成主要受以下因素控制：①持续发育的古构造背景是天然气聚集的有利指向区;②台缘缓坡环境沉积的大面积中—高能颗粒滩是白云岩储集层形成的物质基础;③大气淡水淋滤、白云石化作用叠加断裂带流体溶蚀改造是优质白云岩储集层形成的关键因素;④天然气来源于古油藏裂解和烃源岩分散有机质生烃,北北东向走滑断裂是天然气垂向运移的优势通道;⑤鹰山组一、二段灰岩盖层为气藏形成提供了直接遮挡条件。在此基础上综合分析,指出古城地区鹰山组三段近南北向发育的3个颗粒滩带和北北东向展布的7条走滑断裂带共同控制了滩相白云岩气藏的发育。

下古生界碳酸盐岩是塔里木盆地台盆区重要的勘探领域,累计探明油气地质储量超过22×10⁸ t,但古城地区至今没有大规模发现,烃源条件、储集层规模及油气富集规律不清楚是制约油气勘探的关键。通过系统梳理下古生界碳酸盐岩油气地质条件,得到以下几点认识：①古城地区发育寒武系—下奥陶统斜坡-盆地相烃源岩;②奥陶系鹰山组下段云化滩储集层规模大,储盖组合好,气源断裂发育,是近期增储上产的重要领域,油气富集受储集层和气源断裂控制,中部云化滩带是勘探主攻方向;③寒武系台缘礁滩体规模大,物性好,紧邻烃源岩,有望形成整装气藏,盖层与保存条件是成藏关键,其中Ⅰ、Ⅱ期台缘礁滩体北部保存条件较好,是下步勘探主攻方向;④奥陶系鹰山组上段灰岩断溶体,储集层受断裂控制,规模较小但储盖组合条件好,是值得探索的领域;⑤奥陶系一间房组灰岩颗粒滩发育,含气性好,但暴露溶蚀时间较短,储集层非均质性强,是潜在的勘探领域。图14表2参52

近年来在塔里木盆地台盆区顺南—古城地区中—下奥陶统(6 000~7 200m)、塔中中深井区中—下寒武统(6 400~7 000m)及麦盖提斜坡罗斯2井奥陶系蓬莱坝组(5 800m)深层相继获得天然气发现，气源对比显示天然气主要来源于寒武系。台盆区深层天然气干燥系数(C₁/C_1-4)基本>0.95，以干气为主；天然气甲烷碳同位素值(δ¹³C₁)主要分布在-39.0‰~-33.5‰之间，部分13</sup>C₂)在-39.0‰~-32.0‰之间，与干酪根热模拟实验结果吻合较好，相当于玉尔吐斯组烃源岩在20℃/h升温速率热模拟条件下550~600℃产物。中深1井∈₂a及中深5井∈₁w受寒武系干酪根裂解气晚期充注影响较小，热演化程度相对较低，以低成熟度原油伴生气为主。台盆区海西期以来寒武系过成熟干酪根裂解气对深层油气藏的持续充注，是造成目前台盆区深层天然气干燥系数偏高及碳同位素组成偏重的主要原因。不同地区深层天然气藏受储层物性、构造断裂活动及寒武系过成熟干酪根裂解气差异充注影响，导致不同层段天然气性质差异较大。

In recent years,many natural gas reservoirs have been discovered in the platform-basin region of the Tarim Basin.For example,Shunnan-Gucheng area in the Middle-Lower Ordovician (6 000-7 200m),Tazhong area in the Middle-Lower Cambrian (6 400-7 000m) and Markit Slope Well LS2 in Ordovician Penglaiba Formation (5 800m),the natural gas is mainly from the Cambrian source rocks by the results of gas-source correlation.In the platform-basin region,the dryness coefficient of natural gas (C1/C1-4) was mainly greater than 0.95 and it is defined as dry gas;the isotopic value of methane (δ13C1) was mainly distributed from -39.0‰ to -33.5‰,partly less than -40.0‰;while the isotopic values of ethane (δ13C2) are distributed from -39.0‰ to -32.0‰,which was in accordance with the results of kerogen thermal simulation experiments at 550℃ to 600℃(at 20℃/h).With little influence from the charging of Cambrian kerogen pyrolysis gas and low degree of thermal evolution,the interval of Well ZS1 ∈2a and Well ZS5 ∈1wcontain low maturity of oil associated gas.The impact of the charging of post-mature kerogen pyrolysis gas from Cambrian source rock,led to the deep natural gas with the characteristics of high dryness coefficient and heavy carbon isotope values.The characteristics of deep natural gas in different areas of Tarim Basin vary greatly,the main reasons include physical properties of reservoirs,tectonic fault activity,and differential filling of Cambrian over-mature kerogen pyrolysis gas.

以四川盆地德阳—安岳裂陷槽两侧（裂陷东侧高石梯—磨溪地区和川中古隆起北斜坡；裂陷西侧威远地区和大探1井区）震旦系灯影组天然气藏为研究对象，在充分对比不同地区灯影组天然气地球化学参数（组分、同位素组成）的基础上，明确裂陷槽两侧灯影组天然气地球化学特征差异及其成因。研究表明：①裂陷槽两侧灯影组气藏以原油裂解气为主，成熟度高，为典型的干气；②受较强的硫酸盐热化学还原反应（TSR）改造，裂陷东侧灯影组气藏的H₂S、CO₂含量高，δ¹³C₂偏重（平均值大于?29‰）；威远地区灯影组气藏受TSR影响小，遵循水溶气析出成藏模式，δ¹³C₁较裂陷东侧稍重，部分碳同位素组成发生倒转；大探1井灯影组气藏基本不受TSR影响；③裂陷西侧大探1井区及威远地区基底花岗岩广泛发育且断裂垂向输导高效，灯影组气藏He含量显著高于裂陷东侧；④受烃源岩沉积期的古水介质盐度控制，裂陷西侧灯影组气藏的δ²H_CH4较东侧稍轻；⑤大探1井区灯影组天然气除了来自寒武系筇竹寺组烃源岩外，还有震旦系灯影组三段及陡山沱组烃源岩的贡献。

<p>Leikoupo Formation has become an important target in natural gas exploration of the Sichuan Basin in recent years. Some disputes are remained on both the natural gas source and its generation potential for the Leikoupo Formation. It is indicated that the mean TOC for the argillaceous marl and dolomite arrived at 0.72%, with a comparative high capacity of gas generation. The natural gases are dominated by hydrocarbon component with a low amount of heavy hydrocarbons (round 1%) and have a dryness index of 0.99. Unlike the natural gases found in other marine sequence, the natural gases investigated in this paper contain relatively low concentration of no-hydrocarbons (abundances of CO₂ and N₂less than 10% and H2S in trace amount (&lt;0.01%)). The methane is isotopically somewhat heavy (-31.5&permil; to -36.3&permil;), whereas the ethane has relatively light values mostly less than -28&permil; (-27.7&permil; to -36.6&permil;), with isotopic reversals in partial gas samples, suggesting a post-mature marine gas. Natural gases in Leikoupo Formation are distinguished in isotopic compositions of alkane hydrocarbons from typical terrestrial gas in Xujiahe Formation and marine gas in Feixianguan-Changxing Formation, indicating a different gas source. In conjunction with the character of hydrocarbon source and distribution of source rocks, the close similarity of light hydrocarbons with marls of Leikoupo Formation indicate that the natural gases in Leikoupo Formation are likely from the source rock within this sequence. Through the integrated investigation for the gas accumulation in the Leikoupo Formation, it is found that the source rock occurrence controlled the gas enrichment. Namely, natural gas was only accumulated in &ldquo;lithologic traps&rdquo; (constituted by shoal dolomite and/or fractured limestone) which located near the source rock.</p>

四川盆地中三叠统雷口坡组天然气勘探近年来取得重要突破后继而成为业内关注的热点，但对气源的认识存在较大的分歧。基于天然气地球化学特征开展的成因鉴别和气源对比研究表明，雷口坡组天然气既有主要来自下伏上二叠统龙潭组/吴家坪组烃源岩（磨溪雷一段气藏），断裂下盘须一段烃源岩有一定贡献（中坝雷三段气藏）或供烃条件（川西雷四段气藏），也有主要来自须家河组烃源岩，雷口坡组自身烃源岩有一定贡献（元坝和龙岗雷四段气藏）。雷口坡组气藏具有3种不同的源储组合，其天然气勘探方向具有差异。上二叠统龙潭组烃源岩作为主力烃源岩构成下生上储型，切穿龙潭组至雷口坡组的深断裂周缘的正向构造是寻找雷口坡组规模性气藏的最有利区。上三叠统须家河组底部烃源岩和雷口坡组顶部储层可以构成旁生侧储型，岩溶残丘或岩溶斜坡局部构造高点是这类组合较有利的发育部位。雷口坡组自身构成自生自储型，这类组合往往作为辅助参与气藏形成。

Natural gas exploration in the Middle Triassic Leikoupo Formation (T₂ l) in the Sichuan Basin has achieved great breakthrough in recent years and thus attracts wide attention, however, there is no consensus on the gas source. The genetic identification and gas-source correlation based on the geochemical characteristics of natural gas indicate that, natural gas in the Leikoupo Formation is mainly from the underlying Upper Permian Longtan/Wujiaping Formation (P₃ l/P₃ w) source rocks (Moxi), with assistance (Zhongba) or hydrocarbon supply condition (Chuanxi) by the source rocks in the 1st Member of the Upper Triassic Xujiahe Formation (T₃ x), or mainly from the T₃ x source rocks with certain contribution by the T₂ l source rocks (Yuanba and Longgang). The T₂ l gas pools display three types of source-reservoir assemblages, and they suggest different exploration directions. The P₃ l source rocks as main source rocks can constitute the lower-generation and upper-accumulation pattern, and the positive structures around the deep faults connecting the P₃ l and T₂ l are the most favorable areas to explore large-scale T₂ l gas pools. The source rocks at the bottom of T₃ x and the reservoirs at the top of the T₂ l can constitute the side-generation and side-accumulation pattern, which is favorably developed in the karst residual hills or the local tectonic high position of the karst slope. The T₂ l can constitute self-generation and self-accumulation pattern, which tends to participate assistantly in the formation of gas pools.

鄂尔多斯盆地中东部奥陶系天然气资源丰富，随着深层天然气勘探的进一步深入，在奥陶系盐下地层也相继发现了可观的天然气资源，但盐下天然气的成因类型及来源仍有较大争议。基于天然气的组分、稳定碳同位素等资料，结合实际地质背景，对鄂尔多斯盆地中东部奥陶系马家沟组盐下天然气成因类型及来源进行了系统的分析。研究表明：鄂尔多斯盆地中东部马家沟组盐下天然气以干气为主，非烃含量较低，甲烷碳同位素（δ¹³C₁）值主频分布在-40‰~-32‰之间，乙烷碳同位素（δ¹³C₂）值主频分布在-40‰~-28‰之间，主要表现为腐泥型气特征。综合天然气组分、碳同位素与平面分布特征，将奥陶系盐下天然气细分为油型气、煤型气和混合气，其中油型气分布范围较广，来源于奥陶系马家沟组盐下碳酸盐岩烃源岩，部分天然气发生TSR反应；煤型气和混合气分布范围小，集中在靠近盐下地层尖灭线边缘部位，主要来源于上古生界烃源岩，奥陶系烃源岩也有少量贡献。

The Ordovician natural gas resources are abundant in the middle and eastern of Ordos Basin. With the further exploration of deep natural gas， a mass of natural gas resources have been found in the Ordovician subsalt strata， but the genetic types and sources of subsalt natural gas are still controversial. Based on the data of natural gas composition and stable carbon isotope， combined with the actual geological background， this paper systematically analyzes the genetic types and sources of subsalt natural gas in Majiagou Formation， central and eastern Ordos Basin. The natural gas in the middle and east of Ordos Basin is mainly dry gas， and the gaseous non-hydrocarbon component content is less. The methane carbon isotopes composition （δ¹³C₁） is chiefly between -40 ‰ and -32 ‰， and that of ethane （δ¹³C₂） is between -40 ‰ and -28 ‰， which is characterized by sapropelic origin. According to the composition， carbon isotope and plane distribution characteristics of natural gas， the Ordovician subsalt natural gas can be divided into oil type gas， coal type gas and mixed gas. Oil type gas is widely distributed and comes from the subsalt carbonate source rock of the Ordovician Majiagou Formation， and some natural gas has TSR reaction. The distribution range of coal type gas and mixed gas is small， and they are concentrated near the edge of subsalt formation pinch out line. They mainly come from the Upper Paleozoic source rocks， and the Ordovician source rocks also make a small contribution.

鄂尔多斯盆地的天然气勘探进程与油气地球化学研究进展关系密切，通过对鄂尔多斯盆地中东部地区一批古生界天然气样品的地球化学系统分析，结合前人有关地球化学数据的搜集整理，对古生界天然气进行了地质—地球化学相关分析，着重对产于下古生界奥陶系的天然气组分、碳氢同位素组成等进行分层、分区对比，进一步明确奥陶系各层位天然气的主要来源。结果显示不同层系天然气地球化学特征与成因存在明显差异，奥陶系上组合天然气甲、乙烷碳同位素组成相对略重，且存在部分δ13CCH4>δ13CC2H6的倒转，δDCH4值大多低于-180 ‰；中—下组合天然气碳同位素组成相对偏轻，δDCH4值主体高于-180 ‰；综合认为上组合是上古生界石炭系—二叠系煤型气与下古生界油型气复合，油型气有很大贡献，中—下组合天然气来自奥陶系海相烃源岩自生自储或更深更古老烃源。天然气地球化学特征证明了下古生界具有生烃能力，存在形成规模油气的烃源岩，具有成为未来勘探重点的潜力。

The characteristics of the marine carbonate source rocks and the accumulation and potential of self-sourced natural gas in the Ordovician Majiagou Formation of the Ordos Basin are investigated based on recent exploration progress by using geochemical and gas-source correlation methods. Massive source rocks are developed around the salt depression, east of the paleo-uplift in the Ordovician Majiagou Formation during the Caledonian; and the natural gases produced by argillaceous dolomite and dolomitic mudstone are the major sources of the Ordovician gas field. Besides widespread carbonate weathering crust karst, internal grainstone dolomite is also well-developed in the Majiagou Formation, and both can act as favorable reservoirs. The natural gas of the Majiagou Formation is mainly self-sourced oil-type gas generated by in-situ source rock and accumulated near the source area. There is only limited local accumulation of natural gas produced in the upper strata and stored below. The Majiagou Formation around the salt depression has favorable conditions for large scale natural gas generation and accumulation, has the advantage of collecting large area natural gas of self-generation and self-preservation and the frontier depression areas of the paleo-uplift to the west, north and south of Jingbian gas field are the potential Ordovician exploration targets in the future.

鄂尔多斯盆地是中国第二大沉积盆地,至2002年底已发现4个储量为10¹¹m³以上的大气田.上古生界与煤系有关的烃源岩形成了苏里格、榆林、乌审旗3个位于碎屑岩中的煤成气大气田,在下古生界奥陶系马家沟组碳酸盐岩中发现了靖边气田(其气源仍存在争议).对4个大气田125个气样烷烃气碳同位素分析成果的研究表明,上古生界大气田烷烃气碳同位素组成较重,数值分布域小,表现了煤成气特征,其δ¹³C_iC4>δ¹³C_nC4,各个气田仅发现单项性碳同位素倒转.下古生界靖边气田δ¹³C₁频率主峰值和δ¹³C_B,δ¹³C_T与上古生界具有相似性,也表现出煤成气为主的特征.但靖边气田具有多项性碳同位素倒转,δ¹³C₁,δ¹³C₂,δ¹³C₃数值分布域大,δ¹³C₂较轻,表现出了以煤成气为主油型气为辅的混合气特征.煤成气和油型气的气源均来自上古生界的石炭-二叠系煤系和太原组含煤地层中有机碳丰度高的石灰岩,否定了有机碳含量约为0.20%的马家沟组碳酸盐岩是油型气烃源岩的结论.

The Ordos Basin is the secondary biggest sedimentary basin of China. Four giant gas fields had been proven in the basin, including Sulige, Yulin, Wushenqi and Jingbian gas fields with proven reserves over 100 billion cubic meters for each gas field to the end of 2002. The hydrocarbon source rocks of the Sulige, Yulin and Wushenqi gas fields are coal measures of the Upper Paleozoic. The Jingbian gas field was found in the carbonates of Majiagou Formation in the Ordovician of the Lower Paleozoic. There are still existing arguments about the gas sources of Jingbian gas field. The alkane carbon isotopes analyses of 125 gas samples collected from the above-mentioned four gas fields show that the carbon isotopes of giant gas fields in the Upper Paleozoic are heavy, and the range of values is narrow. The gases are characterized by coal-formed gas. The δ¹³C_<i>i</i>C4 value is bigger than the δ¹³C_<i>n</i>C4 value. Reversal of carbon isotope values in single type appears in the Upper Paleozoic gas fields. In the Lower Paleozoic Jingbian gas field, the δ¹³C₁ dominant peak values, the δ¹³C_B values and the δ¹³C_T values are similar to those in the Upper Paleozoic. However, there are still some different characteristics in Jingbian gas field from other three gas fields. The reversals of carbon isotope values are of multiple types. The values of δ¹³C₁,δ¹³C₂ and δ¹³C₃ are ranged widely, and the δ¹³C₂ value is smaller. These characteristics show that the gases are mixed from mainly humic and some sapropelic sources. It is suggested that the humic and sapropelic sources are all from C-P coal measures and the Taiyuan Formation carbonates with a high abundance of organic matter in the Upper Paleozoic rather than the conventional idea suggested that sapropelic gases are mainly from the Majiagou Formation carbonates with the total organic content of 0.20 %.

元坝气田是迄今为止我国埋藏最深的大型海相气田，有关其海相层系礁滩相储层特征与成藏主控因素的研究取得了重要进展，但对其及邻区长兴组&mdash;飞仙关组天然气成因的认识仍存在分歧。地球化学特征研究表明，元坝气田长兴组&mdash;飞仙关组天然气以烃类气体为主，其中甲烷占主导，干燥系数均高于0.995，非烃气体CO₂和H₂S平均含量分别高达8.55%和6.47%;&delta;¹³C₁值和&delta;¹³C₂值分别介于-31.2&permil;~-27.9&permil;和-29.9&permil;~-25.0&permil;之间，且普遍具有正序特征;&delta;¹³C_CO2值普遍高于-8&permil;，&delta;D₁值介于-156&permil;~-107&permil;之间。元坝气田长兴组&mdash;飞仙关组天然气普遍经历了硫酸盐热化学还原作用的改造，其主体为原油裂解气，主要为龙潭组烃源岩生成的原油后期发生裂解所形成。气藏中的CO₂主体为无机成因，来自酸性流体与碳酸盐岩储层的相互作用。

<p>Yuanba Gasfield is a large gas field in the marine strata with the largest burial depth in China till now,and the studies on the characteristics of reef flat reservoirs in the marine strata and the main controlling factors of hydrocarbon accumulation have achieved significant progresses.However,there is no consensus on the origin of natural gases reservoired in the Changxing-Feixianguan Formations in Yuanba and adjacent area.The study on geochemical characteristics indicates that,the natural gases reservoired in the Changxing-Feixianguan Formations in the Yuanba Gasfield are mainly composed of alkane gases which are dominated by methane with dryness coefficients generally higher than 0.995,and the CO₂ and H₂S display an average content of 8.55% and 6.47%,respectively.The&nbsp;&delta;¹³C₁and&nbsp;&delta;¹³C₂ values are in the range of -31.2&permil;--27.9&permil; and -29.9&permil;--25.0&permil;,respectively,displaying the positive carbon isotopic series.The&nbsp;&delta;¹³C_CO2values are generally higher than -8&permil;,and the &delta;D₁ values are in the range of -156&permil;--107&permil;.The identification of gas origin and gas-source correlation indicate that,the natural gases reservoired in the Changxing-Feixianguan Formations in the Yuanba Gasfield have been altered by thermalchemical sulfate reduction,and they are mainly composed of oil cracked gases derived from the secondary cracking of oil generated by the sapropelic-prone source rocks in the Permian Longtan Formation.The CO₂ in the gas pools are mainly inorganic and were derived from the interaction between acidic fluid and carbonate reservoirs.</p>

硫酸盐热化学还原反应(TSR)是指硫酸盐与烃类作用,将硫酸盐矿物还原生成H2S等酸性气体的过程,是高含H₂S天然气形成的重要机制。由于硫酸盐热化学还原反应是热动力驱动下烃类和硫酸盐之间的化学反应,因此伴随着烃类的氧化蚀变,烃类气体的组分和碳同位素则会发生相应的变化。对四川盆地东北部下三叠统飞仙关组和渤海湾盆地古生界高含硫化氢气藏中烃类气体组分和碳同位素的研究发现,在硫酸盐热化学还原反应消耗烃类的过程中,重烃类优先参与了该反应,从而导致天然气的干燥系数增大。同时,在硫酸盐热化学还原反应过程中,¹²C—¹²C键优先破裂,¹²C更多地参与了该反应,而¹³C则更多地保留在残留的烃类中,使反应后残留的烃类中相对富集¹³C,烃类气体碳同位素值增重2.0&#8240;~4.0&#8240;,且重烃类碳同位素的增重幅度大于甲烷。

The thermochemical sulfate reduction (TSR) refers to the process of sulfate reaction with hydrocarbons,which is the important mechanism for generating natural gas with high content of H₂S and CO₂.Because TSR is the reaction between hydrocarbons and sulfate under the driving of thermal force,the composition of hydrocarbons gas and the carbon isotope maybe vary correspondingly along with the oxidation and alteration of hydrocarbons.The composition of hydrocarbons gas and the carbon isotope of gas reservoirs with high content of H₂S in the Feixianguan Formation of the lower Triassic (T₁f) in the northeastern area of Sichuan Basin and the formation of Paleozoic Erathem in Bohai Bay Basin were studied.It is proved that the heavy hydrocarbons preferentially participated in the reactions of TSR and led to the drying coefficient of natural gas to increase during the process of hydrocarbon depleted by TSR.In the process of TSR,the bond of ¹²C-¹²C ruptured preferentially and more ¹²C participated in the reactions of TSR,while more ¹³C remained in the residual hydrocarbons,which causes the abundant ¹³C distributed in the residual hydrocarbons.Therefore,the drying coefficients of hydrocarbons gas increased after the alteration of TSR.Meanwhile,the increased values of carbon isotope of hydrocarbons gas are from 2.0‰ to 4.0‰. Also,the increasing extent of carbon isotope for heavy hydrocarbons is greater than that of methane.

目前，四川盆地是我国发现含硫化氢气藏数目最多、储量最大的含油气盆地。该盆地产硫化氢的层位众多，从老到新分别有震旦系、石炭系、二叠系及三叠系等。平面上，川东气区硫化氢含量最高，其次为川西气区和川中油气区，川南气区硫化氢含量最低。纵向上，不同层位的含硫化氢气藏内硫化氢的含量存在较大差异。三叠系飞仙关组硫化氢含量最高，其次为二叠系长兴组和三叠系雷口坡组，二叠系茅口组气藏中硫化氢的含量最低。震旦系灯影组和石炭系黄龙组硫化氢含量比较稳定。嘉陵江组气藏中不同层段的硫化氢含量差别较大，其中嘉五段和嘉四段硫化氢含量最高。通过沉积相、埋藏史、热史、包裹体均一温度、硫同位素以及天然气组分等的分析，认为川东气区飞仙关组和长兴组高硫化氢型气藏、川东气区和川南气区的嘉陵江组气藏(除了嘉一段)、川南气区威远震旦系灯影组气藏、川西气区中坝气田雷口坡组气藏以及川中油气区磨溪气田雷口坡组气藏中的硫化氢为硫酸盐热还原反应(TSR)成因；川东气区石炭系黄龙组气藏和川南气区二叠系茅口组气藏硫化氢为含硫有机质热解成因。

At present, Sichuan basin is a petroliferous basin which has the biggest number of H₂S-bearing gas reservoirs and of which the H₂S-bearing gas reserves is also the biggest in China. Reservoirs producingH₂S-bearing natural gas are distributed in Sinian, Carboniferous, Permian, and Triassic. Transversely, the East Gas District(EGD) has the highest content of H₂S, followed by the West Gas District(WGD) and the Middle Oil-Gas District(MOGD), and the South Gas District(SGD) has the least. Vertically, the content of H₂S is various among the different reservoirs and even in different members of the same strata or well. TheH₂Scontent of natural gas in Triassic Feixianguan Formation is the highest, followed by those in the Permian Changxing Formation and in the Triassic Leikoupo Formation, and that in the Permian Maokou Formation is the least. The differences of the H₂S content among different wells in the Sinian Dengying Formation are slight, and the similar phenomenon also exists in Carboniferous Huanglong Formation. SignificantH₂S content differences have been observed in the natural gas from different members of Jialingjiang Formation, in which the gas from the fifth and the forth members have the highest H₂S content. According to the comprehensive analysis of the sedimentary facies, burial history, thermal history, homogenization temperature of the fluid inclusions, as well as the sulfur isotope ratios and the components of the natural gas, it can be concluded that theH₂S of the Feixianguan Formation and the Changxing Formation in EGD, the Jialingjiang Formation(except the first member) in EGD and SGD, the Dengying Formation gas pool of Weiyuan gas reservoir in SGD, the Leikoupo Formation gas pool of Zhongba gas reservoir in WGD and the Leikoupo Formation gas pool of the Moxi gas reservoir in MOGD were generated by the thermochemical sulfate reduction(TSR), while that in the Huanglong Formation in EGD and the Maokou Formation in SGD were generated by the cracking of the organic matter(kerogen or oil ) which contains sulfur.

含硫化氢天然气在全球分布广泛。我国目前已在四川、渤海湾、鄂尔多斯、塔里木和准噶尔等含油气盆地发现了含硫化氢天然气。其中四川盆地川东北气区、华北赵兰庄气田和胜利油田罗家气田为高含硫化氢气田。在对国内外硫化氢研究现状分析和对硫化氢成因机理、成因类型和高含硫化氢气田地质特征研究的基础上,认为上述3个高含硫化氢气田的硫化氢均主要为硫酸盐热化学还原成因(ThermochemicalSulfateReduction,TSR)。

<p>Reservoirs of hydrogen sulfide bearing gas are distribute d widely in globally. The natural gas with H₂S content have been discovered in&nbsp; several petroliferous basins of China which include Sichuan, Bohai bay, E rdos, Tarim and Zhungaer, etc. Among them, the north-eastern gas area of Sichua n basin and the Zhaolanzhuang gas field located in North China, together with th e Luojia gas field located in Shengli oil field of eastern China, are all belong&nbsp; to gas fields with high H₂S contents. According to the analysis and summary o f the current research status of H₂S at home and abroad, based on the probing&nbsp; into the genetic mechanism of H₂S and its classification and combining the geo logical features of the gas fields with high H₂S content, it can be concluded&nbsp; that the above three gas fields were originated mainly from the thermochemical s ulfate reduction (TSR).</p>

塔里木盆地顺北地区4号断裂带发育典型凝析油气藏，凝析油气成因机制与富集主控因素不明制约了勘探向外围的拓展。基于有机地球化学特征与区域地质背景综合分析，明确了顺北4号断裂带凝析油气成因机制与富集主控因素，主要取得以下3点认识：①顺北4号断裂带发育原生的凝析油气藏，凝析油气藏的形成主要受到有机质差异演化，多期成藏以及次生作用影响。②顺北4号断裂带凝析油气藏整体次生作用较弱，但是中段和南段所经历的次生作用相对强于北段；次生作用包括原油裂解作用、气侵作用以及TSR作用。③顺北4号断裂带北段凝析油气藏富集程度明显高于中段和南段；凝析油气富集高产主要受到输导条件以及储层规模控制，断裂活动强度越大，输导条件越好，储层规模越大，膏盐岩越薄也越有利于油气沿走滑断裂向上运移，从而导致油气高产富集。

Typical condensate reservoirs are developed in the No.4 fault zone in Shunbei area of the Tarim Basin. The exploration expansion is restricted by the unclear genetic mechanism and main controlling factors of condensate accumulation.Based on the comprehensive analysis of organic geochemical characteristics and regional geological background， the genetic mechanism and main controlling factors of condensate accumulation of the No.4 fault zone in Shunbei area are identified，and the following understandings are mainly obtained：（1）the condensate oil and gas reservoirs in the No.4 fault zone in Shunbei area are mainly primary condensate reservoirs， and the formation of condensate reservoirs is mainly affected by the differential maturation of organic matter， multi-phase accumulation and secondary alteration； （2） the overall secondary effect of condensate oil and gas reservoirs in the Shunbei No.4 fault zone is relatively weak， but the secondary effect experienced by the middle and southern sections is relatively stronger than that of the northern section； secondary processes include oil cracking， gas invasion， and TSR； and （3） the enrichment degree of condensate oil and gas reservoirs in the northern section of the Shunbei No. 4 fault zone is significantly higher than that in the middle and southern sections； the enrichment and high production of condensate oil and gas are mainly controlled by transport conditions and reservoir size. The stronger the fault activity， the better the transport conditions， the larger the reservoir size， and the thinner the gypsum salt rock， which is more conducive to the upward migration of oil and gas along strike slip faults， resulting in high production and enrichment of condensate.

塔里木盆地海相原油被认为主要来自寒武系-下奥陶统和中-上奥陶统2套烃源岩，但何者为主长期以来存在争议。在前人研究工作的基础上，通过生物标志物对比、馏分碳同位素对比、单体烃同位素对比和碳同位素质量平衡模拟的综合研究，证实了塔北地区海相原油以中-上奥陶统烃源岩贡献为主，最大可达88%，不同地区贡献不同。然而，目前钻井证实的高丰度中-上奥陶统烃源岩分布局限，难以解释塔北地区已发现的广泛分布的特大型海相油田油气资源规模。通过干酪根元素随埋深变化、生烃潜力变化、古TOC恢复等多方面地质地球化学证据证实，塔里木盆地台盆区深部低TOC烃源岩发生过大量生排烃，并根据排烃门限、烃源岩地球化学和测井特征综合判识了有效低丰度烃源岩。在此基础上，采用生烃潜力法评价了塔里木盆地台盆区各成藏体系中-上奥陶统高丰度和有效低丰度烃源岩的排烃量。台盆区中-上奥陶统低丰度烃源岩排烃量为494.4&#215;10⁸t，高丰度烃源岩排烃量为1 353&#215;10⁸t，高、低丰度烃源岩的相对贡献比率分别为73.2%和26.8%。其中，塔北隆起轮南-英买力成藏体系中-上奥陶统烃源岩排烃量为327.7&#215;10⁸t，高、低丰度烃源岩的相对贡献比率分别为59.8%和40.2%，表明低TOC烃源岩对塔里木盆地发现的特大型海相油田的形成具有重要贡献。

The marine crude oil in Tarim Basin is considered to be mainly originated from two sets of source rocks, i.e., Cambrian-Lower Ordovician and Middle-Upper Ordovician, but which is a dominant contributor has been in dispute for a long term. Based on previous research works, through a comprehensive study based on the comparison of biomarkers, fraction carbon isotopes, n-alkane carbon isotopes and the mass balance simulation of carbon isotope, the marine crude oil in Tabei area is confirmed to be mainly contributed by the Middle-Upper Ordovician source rocks (up to 88%), and different regions make different contributions. However, confirmed by current drillings, the high-abundance Middle-Upper Ordovician source rocks show limited distribution, based on which it is difficult to explain the scale of hydrocarbon resource from the giant marine oil field widely distributed in Tabei area. Based on the geological and geochemical evidences including the kerogen elements changing with burial depth, the variation of hydrocarbon generation potential and the paleo-TOC recovery, it is validated that a large scale of hydrocarbon generation and expulsion have occurred in the deep present-day low-TOC source rocks of the platform area, Tarim Basin. In addition, the effective present-day low-TOC source rocks are comprehensively identified according to the hydrocarbon expulsion threshold, source rock geochemistry and logging features. On this basis, the hydrocarbon-generation potential method is adopted to evaluate the hydrocarbon expulsion quantity in the Middle-Upper Ordovician high-abundance and effective low-abundance source rocks of various accumulation systems in the platform area, Tarim Basin. The hydrocarbon expulsion quantity of Middle-Upper Ordovician low-abundance source rocks in the platform area is 494.4&#215;10⁸t, and that from the high-abundance source rocks is 1 353&#215;10⁸t. The relative contribution ratios of high-abundance and low-abundance source rocks are 73.2% and 26.8% respectively. Among them, the hydrocarbon expulsion quantity of Middle-Upper Ordovician source rocks in Lunnan-Yingmaili accumulation system, Tabei uplift is 327.7&#215;10⁸t, and the relative contribution ratios of high-abundance and low-abundance source rocks are 59.8% and 40.2% respectively, indicating that the low-TOC source rocks make an important contribution to the formation of giant marine oilfield discovered in Tarim Basin.

深层—超深层是当前和未来油气勘探的重要方向，明确高演化阶段天然气的生气途径、机制和潜力，将有助于发展天然气成因理论和指导深层油气勘探。结合大量模拟实验和动力学计算，探讨了不同母质和途径生气的成熟度和温度界限（生气时限）及贡献，建立了深层多途径复合生气模式。提出I/II型有机质或干酪根直接热降解（初次裂解）生气下限可延至R_O=3.5%，最大生气量可达120~140 m³/t_TOC，R_O>2.0%阶段的生气量可达20~40 m³/t_TOC。系统认识了原油全组分裂解动力学过程，提出在2 ℃/Ma地质升温速率条件下，液态烃大规模裂解的地质温度为190~220 ℃，对应的成熟度为R_O=2.0%~2.3%；源内残留烃和源外液态烃裂解生气贡献分别为约80 m³/t_TOC和200 m³/t_TOC，乙烷裂解温度要高于230 ℃。硫酸盐热化学还原作用（TSR）导致液态烃裂解温度降低20~40 ℃，加速高含硫化氢（H₂S）天然气藏的高效聚集；无机流体和矿物参与的加氢生气作用可提高天然气生成潜力20%~30%，是深层高—过成熟天然气生成的途径之一。多途径生气过程构成了天然气形成的完整演化序列，揭示在传统油气“死亡线”之下，深层—超深层仍具有天然气勘探潜力。

Deep to ultra-deep formations are important breakthroughs in oil and gas exploration at present and in the future. Understanding of the generation pathway， mechanism and potential of natural gas at high thermal maturation stages is beneficial to develop natural gas generation theory and to guide petroleum exploration in deep formations. Combined with extensive pyrolysis experiments and kinetic calculations， the maturity and temperature stages （gas generation time-limit） as well as potential of gas generation from various sources and pathways were discussed， and a multi-path gas generation model was established. The gas generation from thermal degradation of type I/II kerogens （kerogen primary cracking） can extend to R_O of 3.5% with the maximum yield of 120-140 m³/t_TOC， the potential of kerogen cracking gas at R_O>2.0% can reach 20-40 m³/t_TOC. The kinetics for the cracking of whole oil components were also addressed. It is proposed that intensive cracking of liquid hydrocarbons at a heating rate of 2 ℃/Ma mainly occurs at 190-220 ℃ with the corresponding maturity of R_O=2.0%-2.3%. The contributions of gas derived from thermal cracking of residual hydrocarbons in source rocks and hydrocarbons outside the source are ~80 m³/t_TOC and 200 m³/t_TOC， respectively. The onset temperature for ethane cracking is higher than 230 ℃. Thermochemical sulfate reduction （TSR） leads to a decrease of 20–40 ℃ in temperature for the occurrence of oil cracking， accelerating the efficient accumulation of natural gas with high content of hydrogen sulfide （H₂S）. Besides， gas generation via hydrogenation involving inorganic fluids and minerals promotes gas potential for about 20%-30%， and is one of the pathways for the generation of high-over mature gas in deep formations. The multi-path gas generation process constitutes an integrated evolution sequence of natural gas formation， revealing that there is large-scale gas exploration potential under the traditional “deadline” of oil and gas in deep to ultra-deep formations.

近年来，绵阳—广安浅水陆棚及周缘地区长兴组勘探获得重大突破，但不同礁滩体天然气地球化学特征及含气性差异大，天然气成因来源及主力烃源不清, 油气富集规律及成藏模式不明，制约了有利圈闭评价及勘探部署。基于天然气组成、碳同位素、氢同位素、氮同位素、储层沥青与烃源岩等分析实验数据，系统研究了天然气成因、混源气的混源比例，结合地质研究成果，建立了长兴组气藏成藏模式。研究结果表明：（1）长兴组天然气是以烃类气体为主且干燥系数大于0.98的干气，主要属于原油裂解气，部分为中—高含H₂S气藏。（2）研究区主要发育上二叠统龙潭组/ 吴家坪组Ⅱ₁—Ⅲ型和下古生界筇竹寺组Ⅰ型、龙马溪组Ⅰ—Ⅱ₁型3套烃源岩，长兴组天然气地球化学特征差异与主力烃源岩发育程度及通源断裂断开层位相关。源于上二叠统烃源岩的天然气碳同位素重，δ¹³C₂值主要重于-28.0‰；有下古生界烃源混入时，混合气的碳同位素变轻，采用端元气δ¹³C₂值估算的下古生界源岩贡献比例为53.9%～77.0%。（3）长兴组气藏具有单源供烃、双源供烃和三源供烃3类聚集模式，明确了不同聚集模式的主力烃源岩。研究认为，以上二叠统龙潭组/吴家坪组为烃源的区域，规模滩相储层叠加现今构造是有利勘探区；存在下古生界混源的区域，通源断裂与规模滩相储层的有效匹配，使油气富集程度整体较高，可为四川盆地下步勘探部署决策提供地质依据。

In recent years, significant breakthroughs have been made in the exploration of the Upper Permian Changxing Formation in the Mianyang-Guang’an shallow-water shelf and its adjacent areas. However, the geochemical characteristics and gas-bearing properties of different reef-shoal bodies vary greatly, the genesis and main source rocks of different gas reservoirs remain unclear, and the laws of oil and gas enrichment and the accumulation models are not yet well understood. These factors have restricted the evaluation of favorable traps and the deployment of exploration. Based on the analysis and experimental data of natural gas composition, carbon isotopes, hydrogen isotopes, nitrogen isotopes, reservoir bitumen and source rocks, a systematic study was conducted on the origin of natural gas and the mixing ratio of mixed gases. Combined with geological research results, a gas accumulation model for the Changxing Formation was established. The research results show that: The study results show that: (1) The natural gas in the Changxing Formation is mainly composed of hydrocarbon gases with a dryness coefficient greater than 0.9841, and it is mainly pyrolysis gas from crude oil, with some being medium to high H₂S gas reservoirs. (2) In the study area, three sets of source rocks of two types, namely the Upper Permian Longtan Formation/Wujiaping Formation Type II₁-III and the Lower Paleozoic Qiongzhusi Formation and Longmaxi Formation Type I-II₁, are mainly developed. The geochemical differences of natural gas in the Changxing Formation are related to the development degree of the main source rocks and the stratigraphic level of the source-cutting faults. Natural gas from the Upper Permian source rocks has heavy carbon isotopes, with δ¹³C₂ values mainly heavier than -28.0‰. When Lower Paleozoic source rocks are mixed in, the carbon isotopes of the mixed gas become lighter. The contribution ratio of Lower Paleozoic source rocks estimated by the end-member gas δ¹³C₂ values is 53.9% - 77.0%. (3) The Changxing Formation gas reservoirs have three types of accumulation patterns：single-source，dual-source and triple-source hydrocarbon supply pattern. The main source rocks and their distribution for different accumulation patterns were clarified. It is believed that in the area where the source rocks are from the Upper Permian Longtan Formation/Wujiaping Formation, the superimposition of large-scale beach facies reservoirs and the current structure is a favorable exploration zone. In the area where there is a mixture of Lower Paleozoic sources, the effective matching of source-cutting faults and large-scale beach facies reservoirs leads to a higher overall degree of oil and gas enrichment，which can provide geological basis for the next exploration deployment decisions in Sichuan Basin.

四川盆地深层—超深层领域震旦系—寒武系已发现安岳、蓬莱两个超万亿立方米规模的特大型气田，为寻找接替领域，亟需明确其富集主控因素。在前人研究的基础上，综合应用地质、地球化学资料，对安岳、蓬莱气田天然气成因及成藏主控因素进行系统研究。研究认为，深层- 超深层特大型气田形成主要受控于四大主控因素：（1）晚震旦世-早寒武世发育德阳—安岳和万源-达州2个克拉通内裂陷，控制下寒武统优质主力烃源岩发育，裂陷内烃源岩厚度是邻区的3~4倍，生气强度是邻区的2~3倍；（2）晚震旦世—早寒武世发育安岳—奉节陆架镶边台地，控制震旦系灯影组二段和四段、寒武系沧浪铺组下段和龙王庙组台缘丘滩体或颗粒滩4套优质储层形成，台缘带储层厚度大，储集性能好；（3）桐湾期形成的高石梯—磨溪巨型古隆起长期继承性发育，控制古隆起核部大型构造—岩性和斜坡区岩性圈闭群形成，古隆起核部和斜坡区灯影组圈闭群面积分别达7500km²和5720km²；（4）大型古油藏原位裂解成藏，聚集效率高，不同宿主矿物中发现大量液态烃包裹体，丰度达10%~80%，天然气富集区储层沥青含量高，主要介于1%~8%。根据台地边缘丘滩体、台内滩、规模烃源岩、目的层构造与勘探程度，以及研究区具备立体成藏复式富集的地质条件等因素，评价提出3 类形成大型特大型气田的有利区，Ⅰ类区是已发现安岳、蓬莱气田的安岳—蓬莱台缘丘滩/台内滩发育区；Ⅱ类区是已有突破或具备规模勘探潜力的洪雅—乐山、仪陇—广元、川南荣昌—古蔺、巴中—达州、石柱—利川等台缘丘滩/台内滩发育区；Ⅲ类区是重庆—梁平、威远—泸州等台内滩发育区。研究成果对深层—超深层油气勘探有重要借鉴意义。

基于川中古隆起北斜坡震旦系&#x02014;寒武系天然气藏特征、油气充注史及成藏地质条件分析,研究其天然气成因、成藏演化、聚集模式及大型岩性气藏形成条件。通过天然气组成、碳氢同位素组成、流体包裹体、储集层沥青、岩相古地理及滩体刻画等综合分析,认为：①北斜坡震旦系&#x02014;寒武系天然气主要为原油裂解气,多套烃源岩贡献比例不同导致不同层系天然气地球化学特征差异。②北斜坡震旦系、寒武系气藏均为单斜背景下的岩性气藏,前者为常压,后者为高压;发育单源下生上储,双源下生上储、旁生侧储,双源下生上储、上生下储3类生储盖组合;二叠纪&#x02014;三叠纪是原油主要生成期,早&#x02014;中侏罗世是原油裂解气及湿气主要生成期,晚侏罗世&#x02014;白垩纪是干气主要生成期。③北斜坡震旦系&#x02014;寒武系大型岩性气藏形成的条件主要是斜坡背景下大面积分布的规模滩相储集体邻近源岩或处于古油藏范围,规模丘滩体储集层与滩间致密带封隔层有效匹配形成大型岩性圈闭,有利于近源聚集和古油藏裂解气&#x0201c;原位&#x0201d;规模聚集成藏。研究和勘探成果证实北斜坡发育多层系大型岩性气藏,天然气资源规模超过万亿立方米,勘探潜力大。

基于天然气组分、碳氢同位素、储层沥青、烃源岩条件和源储组合分析，明确了四川盆地开江—梁平海槽两侧长兴组—飞仙关组天然气的来源及其差异，并指出了龙潭组煤成气的有利勘探方向，取得如下认识：①长兴组—飞仙关组天然气主体上以烷烃气为主，均为典型干气；②海槽东侧长兴组—飞仙关组甲、乙烷碳同位素组成明显轻于海槽西侧，西侧的龙岗气田乙烷碳同位素组成要重于元坝气田，而甲烷氢同位素组成则要比元坝气田偏轻；③东岳寨气田、普光气田和元坝气田天然气主要来源于吴家坪组II₁—I型腐泥型有机质；龙岗气田则是煤成气和油型气的混合气，煤成气的比例稍高，来源于吴家坪组II₁—II₂型混合型有机质；④龙潭组内部可形成煤岩气、致密砂岩气和页岩气等多类型气藏。遂宁—泸州、阆中—广安—涪陵一带分别是煤岩气和海—陆过渡相页岩气勘探的有利区带；遂宁—合川、广安—南充一带长兴组礁滩发育区也是煤成气勘探的有利勘探区带。

Through the analysis of natural gas composition， carbon and hydrogen isotopes of alkane gases， reservoir bitumen， source rock conditions， and source-reservoir combination， the gas source differences and sources of natural gas in the Permian Changxing Formation-Triassic Feixianguan Formation on both sides of the Kaijiang-Liangping trough were clarified， and favorable exploration directions for the coal-formed gas generated by the Longtan Formation were pointed out in the Sichuan Basin. The following understanding was obtained： （1） The natural gas in the Changxing-Feixianguan formations is mainly composed of alkane gas， which is typical dry gas； （2） The carbon isotope values of methane and ethane in the Changxing-Feixianguan formations on the east side of the trough are lighter than those on the west side. The ethane carbon isotope in the Longgang Gas Field on the west side is heavier than that in the Yuanba Gas Field， while the value of methane hydrogen isotope is lower than that in the Yuanba Gas Field； （3） The natural gas from Luojiazhai， Puguang， and Yuanba gas fields mainly comes from the sapropelic organic matter of the Wujiaping Formation with kerogen type II₁-I； the Longgang Gas Field is a mixture of coal-formed gas and oil type gas， with a slightly higher content of coal-formed one， originating from the mixed organic matter of the Wujiaping Formation with kerogen type of II₁-II₂； （4） Multiple types of gas， such as coal rock gas， tight sandstone gas， and shale gas， can be formed within the Longtan Formation. The Suining-Luzhou and Langzhong-Guang'an-Fuling areas are favorable zones for the exploration of coal rock gas and marine-continental transitional shale gas， respectively. The reef and shoal development areas of the Changxing Formation in the Suining-Hechuan and Guang'an-Nanchong areas are also favorable exploration areas for coal-formed gas.

通过对中国海相超深层油气区域构造背景、石油地质条件分析及典型地区（古）油气藏解剖,研究海相超深层油气成藏演化过程及富集主控因素。中国海相超深层油气主要分布在四川、塔里木和鄂尔多斯3大克拉通盆地,界定其埋藏深度大于6 000 m,赋存层系为前寒武系及下古生界为主的古老海相层系。中国海相超深层烃源岩发育受全球超大陆聚、散旋回为背景的克拉通裂陷及克拉通坳陷控制,在四川盆地发育层系最多、塔里木盆地其次、鄂尔多斯盆发育规模有待进一步证实;储集层以碳酸盐岩为主,储集性能受早期高能滩体、后期叠加溶蚀及断裂作用共同控制;区域盖层包括膏盐岩、泥页岩与致密碳酸盐岩3大类。中国海相超深层普遍经历了两期油藏、古油藏裂解成气（或部分裂解）、裂解气（或高过成熟油气）晚期定型等演化阶段,油气富集受静态和动态地质要素耦合控制,主力生烃中心、高能相带叠加岩溶规模储集层、巨厚膏盐岩或泥页岩盖层、稳定保持圈闭条件是超深层油气富集关键因素。海相超深层具有克拉通内裂陷周缘、克拉通内坳陷周缘和克拉通边缘3个有利勘探方向。图11表1参42

塔里木盆地塔中地区奥陶系天然气烃类气体以甲烷为主，含量主要分布在75%~95%之间，重烃（C₂+）含量低，为3%~7%，干燥系数介于0.73~0.99之间；非烃气体以N₂和CO₂为主，具高N₂、低CO₂特征，含量分别为4%~8%和2%~6%。天然气&delta;¹³C₁值为-63.1&permil;~-37.7&permil;，&delta;¹³C₂值为-40.6&permil;~-24.8&permil;。天然气在平面上存在较明显差异，Ⅰ号带东段天然气干燥系数高，N₂含量高、CO₂含量低，&delta;¹³C₁值较低，以热裂解成因为主；Ⅰ号带西段干燥系数偏低，N₂含量低、CO₂含量较高，&delta;¹³C₁值较高，以热解成因的伴生气与混合成因气为主；Ⅰ号带中段及主垒带卡1区天然气&delta;¹³C₁值介于两者之间，但前者天然气组分变化比较大，以原油伴生气和腐泥型有机质热解生成的干气为主，而后者天然气干燥系数变化较大，以热解生成的原油伴生气为主。天然气性质上的区带性差别可能与断裂及裂缝的发育程度有关，天然气成藏受喜马拉雅期构造运动的影响，以晚期成藏为主。

基于四川盆地海相大中型气田基本特征分析,结合海相克拉通阶段主要成藏地质单元划分及其对关键成藏要素的控制作用研究,探讨盆地海相碳酸盐岩大中型气田分布规律,指出勘探方向。通过周期性拉张-隆升背景的分析,提出四川海相克拉通阶段发育形成了5个大型古裂陷、3个大型古隆起、5个大型古侵蚀面等大型地质单元,这些地质单元控制了大中型气田的关键成藏要素：①大型古裂陷控制了优质烃源岩生烃中心展布;②大型古裂陷边缘、古隆起高部位、古侵蚀面控制了优质储集层的展布;③大型古裂陷、古隆起、古侵蚀面和现今构造背景联合控制了多类大中型圈闭的形成;④大型地质单元内圈闭继承性演化控制天然气规模聚集。通过大中型气田展布特征与大型成藏地质单元的对比分析,提出单个或多个成藏地质单元与现今构造的叠合关系控制了大中型气田的分布,&#x0201c;三古&#x0201d;叠合区最为有利。德阳&#x02014;安岳古裂陷周缘、龙门山古裂陷东缘、开江&#x02014;梁平海槽及城口&#x02014;鄂西海槽边缘带、环川中水下古隆起高部位、川东&#x02014;蜀南地区茅口组顶界古侵蚀面、川中&#x02014;川西雷口坡组顶界古侵蚀面等,是四川盆地海相碳酸盐岩大中型气田勘探主要领域和方向。图6表2参59

Based on the analysis of the basic characteristics of medium- and large-sized marine gas fields in Sichuan Basin, combined with the division of major reservoir forming geological units in the marine craton stage and their control on key hydrocarbon accumulation factors, the distribution law of medium- and large-sized marine carbonate gas fields in the basin was examined and the exploration direction was pointed out. Through the analysis of the periodic stretching-uplifting background, it is concluded that five large scale paleo-rifts, three large scale paleo-uplifts, five large scale paleo erosion surfaces were formed in the marine craton stage of Sichuan Basin, and these geological units control the key reservoir forming factors of medium and large sized gas fields: (1) Large-scale paleo-rifts control the distribution of high-quality hydrocarbon generation centers. (2) The margin of large-scale paleo-rifts, high position of paleo-uplifts and paleo erosion surfaces control the distribution of high-quality reservoirs. (3) Large-scale paleo-rifts, paleo-uplifts, paleo erosion surfaces and present tectonic setting jointly control the formation of many types of large and medium-sized traps. (4) Natural gas accumulation is controlled by the inheritance evolution of traps in large geological units. Based on the comparative analysis of the distribution characteristics of medium- and large-sized gas fields and large geological units, it is proposed that the superimposition relationship between single or multiple geological units and the present structure controls the distribution of medium- and large-sized gas fields, and the "three paleo" superimposed area is the most advantageous. According to the above rules, the main exploration fields and directions of medium- and large-sized marine carbonate gas fields in Sichuan Basin include periphery of Deyang-Anyue paleo-rift, eastern margin of Longmenshan paleo-rift, margins of Kaijiang-Liangping oceanic trough and Chengkou-western Hubei oceanic trough, the high part of the subaqueous paleo-uplifts around Central Sichuan, paleo erosion surfaces of the top boundary of Maokou Formation in eastern and southern Sichuan Basin, paleo erosion surfaces of the top boundary of the Leikoupo Formation in central and western Sichuan Basin.

Two strike-slip faults, Fault ZG-44 and Fault ZG-10, which cut Well ZG-43 Area in Tazhong Lower Arch are significant to control of hydrocarbon draining. Hydrocarbon migrates upward along these two strike-slip faults from Middle-Lower Cambrian rocks and transport as a T-shaped filling way by both sides within Lower Ordovician Yingshan carbonate reservoir. As from the faults away to their lateral sides, the V/Ni ratios show a decreasing trend and the physical properties of hydrocarbon such as the crude oil density, viscosity, sulfur content and wax content show a progressively increasing trend with increasing the distance to the faults, which can proves migration of the hydrocarbon from the strike-slip faults to their both lateral sides. According to the data from water, oil and gas wells, the altitudes of water, oil and gas beds are below -4 700 m, -4 500~-4 600 m and above -4 500 m respectively. The average gas/oil ratio is relatively high (4 136 m3/m3) in the wells of oil and gas horizon altitude above -4 500 m, and the ratio is relatively low (794 m3/m3) in the wells of oil and gas horizon altitude below -4 500 m. Therefore, the oil, gas and water are in normal differentiation on the whole. The average connectivity radius of oil and gas exploitation to other wells is about 600 m in Well ZG-43 area. As it is less than the radius, significant differences may exist in the upper limit of the barrier layer´s physical properties in time scales of both hydrocarbon accumulation and exploitation.

中国海相碳酸盐岩大气田主要分布在四川、塔里木和鄂尔多斯三大克拉通盆地,层系上主要富集在中下三叠统、上二叠统、石炭系、奥陶系及震旦系5大层系。截至2010年底,12个碳酸盐岩大气田储量为1.69&times;10¹²m³,占全国45个大气田储量的27.2%。碳酸盐岩大气田由单个或多个相对独立的大中型气藏组成;储层总体以低孔为主,并有随储层时代变新其孔隙度增大的趋势,单个气藏储量&gt;10&times;10⁸m³的储层平均渗透率以&gt;1 mD为主;有效储层厚度一般为15~75 m,含气面积主要为10~100 km²;储量丰度除鄂尔多斯盆地靖边大气田为0.56&times;10⁸m³/km²外,其他多&gt;5&times;10⁸m³/km²,表现为中&mdash;高丰度特征;埋藏深度范围大(1 000~6 370 m),以超深层、深层&mdash;中深层为主;气藏压力系数除磨溪气田&gt;2.0外,其他多&lt;1.3,主要表现为常压;由构造、岩性(含古潜山)等圈闭所组成的复合型气藏是碳酸盐岩大气田的主要气藏类型。继承性大型古隆起、多套优质烃源岩的高强度充注、断裂及侵蚀沟槽的有效输导、大面积溶蚀孔洞型空间的规模聚集、膏盐岩及泥质岩的有效封盖等要素的时空有效配置造就了碳酸盐岩天然气的规模富集与成藏。高地温场背景下的古油藏原油裂解形成干气藏、煤成气与液态烃裂解气混合形成干气藏、低地温场背景下的油藏受到干气气侵作用形成凝析气藏是碳酸盐岩大气田的三类典型成藏模式。