中国西部叠合盆地油气藏形成、演化与分布预测

中国西部叠合盆地经历了多期构造变动和多旋回的油气成藏作用,研究叠合盆地油气藏的形成、演化和分布预测具有重要的意义。叠合盆地指不同时期形成的不同类型的沉积盆地或地层在同一地理位置上的叠加和复合,具有地层沉积不连续、地层构造不连续、地层应力应变作用不连续等三大标志性特征,依据构造剖面上地层年代的关联性,将叠合盆地分为五种类型,即连续沉积型叠合盆地、中晚期地层叠合盆地、早晚期地层叠合盆地、早中期地层叠合盆地、长期暴露型叠合盆地。叠合盆地普遍发育复杂油气藏,三种作用（剥蚀作用、断裂作用、褶皱作用）六种机制（渗漏、扩散、溢散、氧化、降解和裂解）形成复杂油气藏,依据成因特征分为五类,原成型油气藏,圈闭调整型油气藏,组分变异型油气藏,相态转换型油气藏,规模改造型油气藏。研究表明,复杂油气藏中天然气的地下产状特征和分布特征与地表产状特征和分布特征有很大差异。中国西部叠合盆地油气分布主要受烃源灶、古隆起、沉积相、断裂带、构造变动和区域盖层等六大因素的控制。其中烃源灶（S）、古隆起（M）、沉积相（D）和盖层（C）等四大要素控制着油气成藏的形成和分布,并建立了多要素匹配（T-CDMS）成藏模式,用以预测有利成藏领域。油气藏形成之后,多期的构造变动对早成的油气藏进行调整、改造和破坏,主要受构造变动强度、构造变动时间、构造变动次数、构造变动时盖层的封油气性能等四大要素控制,并以此建立了多期构造变动破坏油气藏后剩余潜力评价模型,利用这一模型可以预测出有利勘探区带并评价出有利勘探区带中的剩余资源潜力。油气藏经过改造,表现出晚期成藏效应,并受相势耦合作用的控制最后定位,利用晚期成藏效应和相势耦合理论可以预测有利勘探目标,并指出潜在有利勘探目标。     

论塔里木盆地构造体系控油作用

塔里木盆地是多构造体系复合的大型含油气区,盆内二级构造体系控制生油拗陷和油气富集带三、四级扭动构造控制油气田。多构造体系复合型盆地油气藏特征是多含油气系统、多油气藏类型、多成藏期和油气田(藏)县4个并存等。      

从油气运移探讨有机质在成矿中的作用

本文从盆地中有机质热演化成烃、烃类物质经过初次运移和二次运移形成油气藏以及油气藏破坏的烃类运聚演化过程探讨了有机质在成矿中的作用。来自于盆地中沉积地层的烃类物质和成矿流体具有相同的辅导体系，因而两者通常在同一种流体介质中运移。来自烃源岩的流体的盐度很低（20－30g/L），说明流体从烃源岩中萃取的成矿物质的量有限。在油气的二次运移阶段，烃类物质使流体保持酸性环境，从而加速了流体演变为成矿流体的速度。同时，有机质通过络合、还原和吸附作用参与了成矿物质的搬运，油气成藏的过程也是成矿 流体聚集的过程。油藏（reservoir0的破坏使流体发生剧烈的物化条件改变，从而导致了矿质沉淀形成矿床。     

再论陆相三级层序内四分方案及其在油气勘探中的应用

结合在陆相盆地中的实例研究,将一个发育完整的陆相三级层序细分为4个体系域：低水位体系域（LST）、水进体系域（TST）、高水位体系域（HST）和水退体系域（RST）,称为I型层序。或者一个层序可以不发育低水位体系域,而由水进体系域、高水位体系域和水退体系域组成,称为II型层序。低水位体系域发生在湖平面（基准面）快速下降时期;水进体系域出现在首次湖泛面到最大湖泛面之间;高水位体系域形成在高水位时期的湖平面相对静止期;水退体系域形成在湖平面缓慢下降期,在沉积物供给速率大于可容空间增加速率时形成。一般低水位体系域发育小型进积式准层序组,纵向沉积环境变浅,在盆地边缘形成河流下切作用;水进体系域发育退积式准层序组,沉积环境自下而上明显变深;高水位体系域发育加积型准层序组,纵向沉积环境变化不大,且多为静水沉积;水退体系域发育大型进积式准层序组,沉积环境自下而上明显变浅,沉积体系向盆地中心推进。结合对松辽盆地的实例研究,分别阐述了断陷盆地和坳陷盆地中各不同体系域的油气藏分布规律：低水位体系域主要在断陷盆地的陡坡侧和坳陷盆地的深水区发育透镜状岩性油气藏;水进体系域主要在断陷盆地的陡坡带发育上倾尖灭型岩性油气藏,在缓坡带和坳陷盆地的斜坡带发育地层超覆油气藏;高水位体系域主要以深水区的透镜状岩性油气藏为主;水退体系域在断陷盆地中主要发育地层不整合遮挡油气藏,在坳陷盆地中主要发育断块油气藏以及断层遮挡油气藏。从而,以理论与实践相结合的方式,阐明了陆相层序四分体系域的实用性。     

右江盆地含油气成矿流体性质及其成藏-成矿作用

右江盆地含油气成矿流体是一种多组分、多相态的不混溶体系,成藏流体具低温(多为90～160℃)和低盐度(多小于6wt%NaCl)的特征,其主要组分是有机质、CO2和H2O;金矿成矿流体以中低温(多集中于150～250℃)和低盐度(0.4～6.7wt%NaCl)为特征,其主要组分为H2O和CO2,次为烃类有机组分。盆地内古油藏与金矿床在空间上密切共存,在成藏和成矿流体活动时限上基本一致,在成因上一脉相承,表明两者均为盆地有机成矿流体演化的产物。加里东晚期至印支中期,"盆-台相间"的沉积构造格局为成矿和成藏奠定了物质基础,盆地有机成矿流体的活动使油气和金属分别聚集形成油气藏和金属矿床。印支晚期至燕山早期,伴随褶皱造山作用的盆地流体活动使油气的原始分布格局发生改变,并造成了油气和金属矿床的空间分带。燕山中晚期强烈的构造抬升剥蚀,使油气藏和金属矿床遭受强烈的破坏与改造。     

试论油气运移对砂岩型铀矿成矿作用的影响

以油气成藏动力系统和砂岩型铀矿成矿动力系统为单元，分析了砂岩型铀矿床与油气藏沉积体系、矿床（藏）聚集带特征及不同矿集带之间的联系。认为油气多次运移促使砂岩型铀矿成矿是一种普遍地质作用，指出油气运移成藏过程中散失部分对砂岩型铀矿成矿促进性表现形式为油气成分使铀矿化预富集或使层间氧化带型铀矿化中止与矿体封存，油气成藏后三次运移（微渗）使红色砂层中铀富集成矿。依据油气对砂岩型铀矿还原作用的结果初步建立了3种油气与砂岩型铀矿共存的基本模式，丰富了砂岩型铀矿成矿理论，为多能源综合开发提供参考。     

多种能源矿产同盆共存富集成矿(藏)体系与协同勘探-以鄂尔多斯盆地为例

以鄂尔多斯盆地为例,在盆地构造演化、各种能源矿产的时空分布以及相互联系等方面分析的基础上,探讨了盆地演化进程中多种能源矿产同盆共存富集的成藏（矿）体系及其分布规律,试图建立多种能源矿产协同勘探模式。研究表明,鄂尔多斯盆地砂岩型铀矿的形成与油、气、煤具有成生关系,典型矿床为东胜铀矿床。可以把同盆共存富集的各种等能源矿产概括为无机矿产（铀矿）和有机矿产（油、天然气、煤及煤层气）两类,在整个盆地演化过程中,共存系统中有机和无机矿产的形成过程相互关联,就位空间按照一定的规律分布,通常有机矿产分布于盆地内部,无机矿产则分布于盆地边缘或盆－山转换部位,但它们同属一个盆地的自然成矿（藏）系统。对于鄂尔多斯盆地,晚侏罗世-早白垩世的构造作用和后期改造,对多种能源矿产的共存成矿（藏）体系的形成及定位产生了重要影响。主要成藏（矿）演化过程可划分为成矿（藏）准备、主要成矿（藏）和后期保存等三个演化阶段。根据盆地油、气、煤、铀多种能源矿产的配置组合特征,将鄂尔多斯盆地划分为七个协同勘探区,可以分别采用不同的协同综合勘探方式。     

论盆地流体成矿/成烃作用的耦合关系

沉积盆地中的油气聚集和某些金属矿床都是盆地演化过程中盆地流体活动的产物,是同一地质-构造格架内同一自然过程留下的物质表象。油气是被封存起来的、以碳氢化合物为主的盆地有机流体,而固态的金属矿石则大多是以水溶液相为主的盆地流体在适当的部位将所溶解携带的成矿金属组分沉淀卸载的结果。碳氢化合物源干沉积有机质的演化;成矿金属元素则可能是盆地流体从沉积物颗粒通过流-岩反应萃取来的。有机组分在成矿金属元素的活化萃取、迁移、直至沉淀就位的全过程中均起了非常重要的作用。在成岩压实作用阶段(相当干油气的初次析出阶段),油气与粘土水一道从生烃层内被挤出。从这个意义上讲,油气与部分成矿水溶液具有共同的起源。但在往后的运移和聚集就位过程中,由于水和油的物理化学特征不同,二发生了分离。从而造成了金属矿床与油气藏在空间上既相互依赖,又相互分离的复杂关系。     

云南金顶超大型铅锌矿床沥青Re-Os法测年及地质意义

油气藏与金属矿床在世界许多沉积盆地内共存,油气成藏与金属成矿的动力学关系备受关注。云南兰坪金顶产有中国目前最大铅锌矿床,也是世界上唯一陆相沉积岩容矿、且形成于新生代的超大型铅锌矿床。矿床中常见沥青、重油等有机质,它们的形成早于或晚于铅锌硫化物成矿存在明显分歧,限制了对油气成藏与铅锌成矿关系的认识。本文针对金顶超大型矿区以古新统云龙组含砾砂岩和砂砾岩为主岩铅锌矿石中沥青,开展了Re-Os法同位素测年,获得68±5Ma的等时线年龄(MSWD=9.2,n=6),指示金顶古油气成藏形成于古新世,先于铅锌硫化物大规模成矿;烃类物质具有通过热化学还原硫酸盐提供铅锌成矿所需硫化氢的客观条件;油气成藏与铅锌成矿在云南金顶矿区很可能是一个先后发生的连续地质过程,成藏为成矿奠基,成矿伴随着油气藏的破坏。     

内蒙古二连盆地岩性油藏形成与分布的优势性特征

近几年在内蒙古二连盆地岩性油藏勘探方面的突破表明,岩性油气藏的形成和分布比构造油气藏更具优势性特征。岩性油气藏形成的优势性表现在：（1）岩性圈闭多期形成有利于多期捕集油气;（2）近源短距离运移有利于成藏;（3）低部位岩性圈闭比高部位构造圈闭成藏期要早;（4）相对有利的盖层条件。保存条件也比构造油气藏要更具优势：（1）抬升剥蚀对岩性油藏的破坏程度小于对构造油藏的;（2）断层破坏对岩性油藏的破坏程度小于对构造油藏的。岩性油气藏的空间展布范围也更广阔：（1）同构造油藏相比,其分布范围更宽,陡坡带、缓坡带和洼槽带均可分布;（2）岩性油藏分布的体系域更宽,低水位体系域和高水位体系域都有富集;（3）岩性油藏分布的压力场更宽,在各种压力场环境中都有发现。因此,提出二连盆地岩性油气藏形成和分布具有“优势性特征”的观点。     

有机烃新方法在金矿床快速定位预测中的应用:以陕西八卦庙特大型金矿床为例

有机质对金属元素的迁移、沉积和富集成矿有重要的作用，有机烃是有机质最终的裂解产物，具有很强的挥发性和穿透性。研究发现，八卦庙金矿床有机烃与金矿体品位呈密切相关关系，矿床的矿化富集中心也是有机烃的浓集中心。利用有机烃的这一特点可以进行隐伏金矿床的定位预测研究。     

Yanshanian–Himalayan geodynamic transformation of the northwestern Junggar Basin,southwestern Central Asian Orogenic Belt (CAOB), and its significance for petroleum accumulation

The northwestern Junggar Basin in the southwestern Central Asian Orogenic Belt is a typical petroliferous basin. The widely distributed reservoirs in Jurassic–Cretaceous strata indicate that the region records Yanshanian–Himalayan tectonic activity, which affected the accumulation and distribution of petroleum. The mechanism of this effect, however, has not been fully explored. To fill the knowledge gap, we studied the structural geology and geochemistry of the well-exposed Wuerhe bitumen deposit. Our results indicate that deformation and hydrocarbon accumulation in the northwestern Junggar Basin during the Yanshanian–Himalayan geodynamic transformation involved two main stages. During the Yanshanian orogeny, a high-angle extensional fault system formed in Jurassic–Cretaceous strata at intermediate to shallow depths owing to dextral shear deformation in the orogenic belt. This fault system connected at depth with the Permian–Triassic oil–gas system, resulting in oil ascending to form fault-controlled reservoirs (e.g., a veined bitumen deposit). During the Himalayan orogeny, this fault system was deactivated owing to sinistral shear caused by far-field stress related to uplift of the Tibetan Plateau. This and the reservoir densification caused by cementation formed favorable hydrocarbon preservation and accumulation conditions. Therefore, the secondary oil reservoirs that formed during the Yanshanian–Himalayan tectonic transformation and the primary oil reservoirs that formed during Hercynian–Indosinian orogenies form a total and complex petroleum system comprising conventional and unconventional petroleum reservoirs. This might be a common feature of oil–gas accumulation in the Central Asian Orogenic Belt and highlights the potential for petroleum exploration at intermediate–shallow depths.     

准噶尔盆地克-百地区中生界输导层及物性下限与成藏关系

渗透性地层称为输导层,它是油气运移的通道。输导层的油气输导能力与岩层物性有密切关系。物性越好,输导能力越强,物性越差,输导能力越差。通过克-百地区中生界输导层的研究,油气输导层的物性下限不是一个固定值,输导物性下限与埋深、原油性质和总体物性条件有关。输导层的分布直接控制油藏的分布,只有分布在有效输导层上的圈闭才能形成油藏。     

论油气成藏与金属成矿的关系及综合勘探

从油气藏及金属矿藏的来源、运移、成藏/成矿等方面对油气成藏和金属成矿之间的关系进行了论述,指出油气藏和沉积金属矿藏均来自于相同的烃源岩/矿源层。一些金属(铀、黄铁矿等)的存在,有可能对有机质向烃类的转化起到了积极的催化作用,而烃类中的有机酸对金属元素具有溶解、螯合作用,有利于金属元素随烃类和成矿流体的析出。烃类和成矿流体在水-油-岩共存体系,在近乎相同的运移机制和路径中,能够一起溶解、萃取其路径上的金属元素,有利于金属元素的运移。油气与成矿流体可以在圈闭中聚集、成藏或者由于物理化学条件的变化,金属矿物独立沉淀成矿。油气与金属的成藏/成矿在时间和空间上也具有某些相似性。因此油气成藏和金属成矿具有非常密切的关系,有利于对二者进行综合勘探和利用,具有非常重要的现实意义。     

北部湾盆地涠西南凹陷湖底扇的沉积特征

综合利用岩芯、测井、地震和粒度曲线等资料,研究了涠西南凹陷古近系流沙港组一段湖底扇的沉积特征。结果表明,湖底扇具有典型浊积岩的鲍马序列特征,且分为高能量型沉积和低能量型沉积两种,在沉积结构上,粒度概率图和C-M图具有浊流沉积独有的粒度分布特征,同时具有丰富的浊流沉积构造现象。涠西南湖底扇在陡峭的古地貌和充足的物源供应条件下形成,沉积在断裂坡折带或同沉积坡折带坡脚的深水区。湖底扇沉积于深水区,圈闭条件好,临近烃源岩,油源富足,易于形成油气藏,已有多口井钻获工业油流,勘探前景广阔。     

Genetic link between Mississippi Valley-Type (MVT) Zn-Pb mineralization and hydrocarbon accumulation in the Nanmushu,northern margin of Sichuan Basin,SW China

The coexistence of Zn-Pb deposits and oil/gas reservoirs demonstrates that a close genetic link between them. The Nanmushu is a large Mississippi Valley-Type (MVT) Zn-Pb deposit discovered on the northern margin of the Yangtze block in recent years. The deposit is hosted in the Ediacaran Dengying Formation dolostone, accompanied by large amount of bitumen in the orebodies. The MVT Zn-Pb deposit overlaps with the paleo-oil/gas reservoir horizontally, and sandwiched in the paleo-oil/gas reservoirs at depth. The Cambrian Guojiaba Formation may have provided not only the oil for paleo-oil/gas reservoirs, but also ore metals for the Zn-Pb mineralization. With increasing burial depth, the Guojiaba Formation may have become more mature to form metal-rich fluids, and the metals migrated and accumulated with hydrocarbons to form a paleo-oil reservoir. Large-scale Zn-Pb mineralization may have occurred in the destruction process of paleo-gas reservoir. With the deep burial of paleo-oil reservoir, the paleo-oil reservoir may have transformed into a paleo-gas reservoir. Decoupling of metals and hydrocarbons during the paleo-gas reservoir formation may have provided the ore metals. Thermal sulfate reduction (TSR) during the paleo-oil/gas reservoirs formation may have provided the hydrogen sulfide for mineralization. Decompression and cooling during the paleo-gas reservoir destruction may have formed extensive metal sulfide precipitation and mineralization.     

Alteration and Reformation of Hydrocarbon Reservoirs and Prediction of Remaining Potential Resources in Superimposed Basins

<正>Complex hydrocarbon reservoirs developed widely in the superimposed basins of China formed from multiple structural alterations,reformation and destruction of hydrocarbon reservoirs formed at early stages.They are characterized currently by trap adjustment,component variation, phase conversion,and scale reformation.This is significant for guiding current hydrocarbon exploration by revealing evolution mechanisms after hydrocarbon reservoir formation and for predicting remaining potential resources.Based on the analysis of a number of complex hydrocarbon reservoirs,there are four geologic features controlling the degree of destruction of hydrocarbon reservoirs formed at early stages:tectonic event intensity,frequency,time and caprock sealing for oil and gas during tectonic evolution.Research shows that the larger the tectonic event intensity,the more frequent the tectonic event,the later the last tectonic event,the weaker the caprock sealing for oil and gas,and the greater the volume of destroyed hydrocarbons in the early stages.Based on research on the main controlling factors of hydrocarbon reservoir destruction mechanisms,a geological model of tectonic superimposition and a mathematical model evaluating potential remaining complex hydrocarbon reservoirs have been established.The predication method and technical procedures were applied in the Tazhong area of Tarim Basin,where four stages of hydrocarbon accumulation and three stages of hydrocarbon alteration occurred.Geohistorical hydrocarbon accumulation reached 3.184 billion tons,of which 1.271 billion tons were destroyed.The total volume of remaining resources available for exploration is～1.9 billion tons.     

Dynamic Field Division of Hydrocarbon Migration,Accumulation and Hydrocarbon Enrichment Rules in Sedimentary Basins

Hydrocarbon distribution rules in the deep and shallow parts of sedimentary basins are considerably different, particularly in the following four aspects. First, the critical porosity for hydrocarbon migration is much lower in the deep parts of basins: at a depth of 7000 m, hydrocarbons can accumulate only in rocks with porosity less than 5%. However, in the shallow parts of basins (i.e., depths of around 1000 m), hydrocarbon can accumulate in rocks only when porosity is over 20%. Second, hydrocarbon reservoirs tend to exhibit negative pressures after hydrocarbon accumulation at depth, with a pressure coefficient less than 0.7. However, hydrocarbon reservoirs at shallow depths tend to exhibit high pressure after hydrocarbon accumulation. Third, deep reservoirs tend to exhibit characteristics of oil (–gas)–water inversion, indicating that the oil (gas) accumulated under the water. However, the oil (gas) tends to accumulate over water in shallow reservoirs. Fourth, continuous unconventional tight hydrocarbon reservoirs are distributed widely in deep reservoirs, where the buoyancy force is not the primary dynamic force and the caprock is not involved during the process of hydrocarbon accumulation. Conversely, the majority of hydrocarbons in shallow regions accumulate in traps with complex structures. The results of this study indicate that two dynamic boundary conditions are primarily responsible for the above phenomena: a lower limit to the buoyancy force and the lower limit of hydrocarbon accumulation overall, corresponding to about 10%–12% porosity and irreducible water saturation of 100%, respectively.     

The relationship between hydrocarbon accumulation and Mississippi Valley‐type Pb‐Zn mineralization of the Mayuan metallogenic belt,the northern Yangtze block,SW China: Evidence from ore geology and Rb‐Sr isotopic dating

The coexistence of Pb‐Zn deposits and oil/gas reservoirs demonstrates that a close genetic connection exists between them. The spatiotemporal relationship between Pb‐Zn mineralization and hydrocarbon accumulation is the key to understanding this genetic connection. The Mayuan large‐scale Pb‐Zn metallogenic belt is composed of a number of Mississippi Valley‐type (MVT) Pb‐Zn deposits that were recently discovered on the northern margin of the Yangtze Block, China. It is hosted in the dolostone of the Sinian (Ediacaran) Dengying Formation (Z₂dn). In addition to the abundant bitumen in the Mayuan Pb‐Zn metallogenic belt, the paleo‐oil reservoir and the MVT Pb‐Zn deposit overlap in space. In this study, two precise ages of 468.3 ± 3.8 Ma and 206.0 ± 6.5 Ma were obtained via the Rb‐Sr isotopic dating of galena and sphalerite from the Mayuan Pb‐Zn metallogenic belt, respectively. The early metallogenic age of 468.3 ± 3.8 Ma is similar to the previously published age of 486 ± 12 Ma. The age of 206.0 ± 6.5 Ma is consistent with the age of the metallogenic event that occurred at 200 Ma in the Upper Yangtze Pb–Zn metallogenic province of the Sichuan‐Yunnan‐Guizhou polymetallic zone, which is located on the southwest margin of the Sichuan Basin, suggesting that the metallogenic effects of this period were regional in scale in the peripheral areas of the Sichuan Basin. Previous studies have shown that two periods of hydrocarbon accumulation occurred in the oil/gas reservoir that coexists with the Pb‐Zn deposits in the study area. The Pb‐Zn mineralization at 468.3 ± 3.8 Ma occurred during the first period of hydrocarbon accumulation, while the second mineralization at 206.0 ± 6.5 Ma occurred during the transformation of the paleo‐oil reservoir to a paleogas reservoir. The spatial relationship between the paleo‐oil/‐gas reservoir and the MVT Pb‐Zn deposits and the temporal relationship between mineralization and hydrocarbon accumulation show that a close genetic relationship exists between the MVT Pb‐Zn mineralization and hydrocarbon accumulation. Analysis of metals in the source rocks forming the paleo‐oil/‐gas reservoirs show that source rocks which formed paleo‐oil/‐gas reservoirs may have provided metals for Pb‐Zn mineralization. Both the paleo‐oil/‐gas reservoirs and Pb‐Zn mineralizing fluids had the same origin.