泥灰岩的生、排烃模拟实验研究

本文采用加水热模拟实验方法对东濮凹陷卫城地区下第三系低熟泥灰岩进行了生、排烃模拟实验研究，重点分析了液态产物（热解油、沥青Ａ、沥青Ｃ）的特征及演化规律。热解油中轻质烃（Ｃ₆－Ｃ₁₄）占有重要的地位，其相对含量随演化程度的增高变化特征是从大到小然后再增大，轻质烃的准确定量为评价泥灰岩的生油量提供了重要参数；热解油、沥青Ａ、沥表Ｃ三者的产率及组成变化的对比研究反映了泥灰岩（碳酸盐岩）中不同赋存状态有机质对成烃的贡献以及排烃机制。     

含油气盆地油气同位素地球化学研究概述

以气体地球化学国家重点实验室工作为主，简要概述了对我国含油气的同位素地球化学研究。1．烃气的同位素地球化学：讨论了天然气成因新模式与气藏烃气同位素组成的关系，低演化阶段天然气同位素分馏的二阶段模式，云南中小盆地天然气低演化系列同位素特征及用储层解析气作油气源对比。2．稀有气体同位素地球化学：阐述了^3He/^4He值与中国构造分区，幔源氮的复合成藏和幔源甲烷问题以及气源对比等。3．液态烃同位素地球化学：简述了轻烃碳氢同位素特征及氢同位素作为判别古沉积介质盐度的指标，概述了未熟一低熟油同位素特征及在自然剖面上油和源油抽提物碳同位素分馏特征及其机理。     

含油气盆地油气同位素地球化学研究概述①

以气体地球化学国家重点实验室工作为主,简要概述了对我国含油气的同位素地球化学研究。1. 烃气的同位素地球化学:讨论了天然气成因新模式与气藏烃气同位素组成的关系,低演化阶段天然气同位素分馏的二阶段模式,云南中小盆地天然气低演化系列同位素特征及用储层解析气作油气源对比。2. 稀有气体同位素地球化学:阐述了3He/4He值与中国构造分区, 幔源氦的复合成藏和幔源甲烷问题以及气源对比等。3. 液态烃同位素地球化学:简述了轻烃碳氢同位素特征及氢同位素作为判别古沉积介质盐度的指标,概述了未熟-低熟油同位素特征及在自然剖面上油和源岩抽提物碳同位素分馏特征及其机理。     

东营凹陷民丰地区天然气生成机理与化学动力学研究

民丰地区天然气存在源岩热解和原油裂解成因的争议。本文采用高压釜封闭体系对该区烃源岩和原油样品分别进行了热模拟实验,从烃类气体生成过程、气态烃与部分单体烃生成动力学特征讨论了二者的生气机理,认为原油裂解比源岩热解生气活化能高30～40 kJ/mol,原油比源岩生气需要更高的热力学条件。模拟实验证实,成熟阶段源岩热解气与原油裂解气相比,以环烷烃和芳烃相对含量低为特征,与民丰地区产出的天然气组成更接近,据此认为该区天然气主要为源岩热解成因。     

柴达木盆地第三系油源对比

本文利用生物标记化合物,着重讨论了柴达木盆地第三系内陆盐湖相地层中的油源对比问题.主要应用甾烷的母源参数与成熟度参数相结合的方法,和油/岩综合指纹类型曲线对比法.查明了这组同时代但不同成熟度的原油,各有其相应成熟级别(未成熟、低成熟、成熟和高成熟)的源岩.表明它们是不同成烃演化阶段的产物.研究证明,迄今柴达木盆地所找到的石油,大部分是低成熟的,而成熟和高成熟的油气资源还有很大的勘探前景.     

Low-mature gases and their resource potentiality

In the 80’s of last century, based on the advances in natural gas exploration practice, the concepts of bio-thermocatalytic transitional-zone gas and early thermogenetic gas were proposed, and the lower limit Ro values for the formation and accumulation of thermogenetic natural gases of industrial importance have been extended to 0.3%–0.4%. In accordance with the two-stage model established on the basis of carbon isotope fractionation involved in the formation of coal-type natural gases, the upper limit Ro ...     

Hydrous pyrolysis of sediments: Composition and proportions of aromatic hydrocarbons in pyrolysates

Hydrous pyrolysis (closed vessel autoclaving in the presence of excess water) of organic-rich rocks is said to generate oils which closely resemble natural crude oils in their broad characteristics and composition. However there are only a few accounts of the proportions and compositions of hydrocarbons in hydrous pyrolysates and none of these discuss the aromatic hydrocarbon composition in detail. The present paper presents some data on the latter.Hydrous pyrolysis (3 days) of a dolomitic siltstone (Permian, Marl Slate) at 280, 300,320, 340 and 360°C produced significant amounts of oils in which the aromatic hydrocarbons were one and a half to two times as abundant as the saturated hydrocarbons.The overall composition of the aromatic hydrocarbons was similar to most crude oils; the major components isolated by our methods from natural oils and from pyrolysates were C_1–4 alkylnaphthalenes. At the lowest pyrolysis temperature (280°C) the distributions of the more minor components of the pyrolysates (e.g. alkylphenanthrenes, aromatic steroids) were also generally similar to those found in natural crudes. However, a number of components (e.g. methylanthracenes, Diels' hydrocarbon) which are not usually reported in crudes, were also detected and the relative proportions of these increased at the higher temperatures. Hydrous pyrolysis (340°C) of an organic-rich oil shale (Jurassic, Kimmeridge) and an asphaltic-material containing no minerals produced pyrolysates in which many of these unusual compounds were also present. In addition the pyrolysate of the oil-shale contained higher proportions of organic sulphur compounds. It appears that the formation of the unusual compounds is not simply a function of the type of organic matter or mineralogy but rather of the high temperatures or fast heating rates employed.     

Geochemical characteristics of aromatic hydrocarbons in saline lacustrine crude oils and their significance as exemplified by the south area of western Qaidam Basin

Based on quantitative GC-MS analysis of 40 crude oil samples collected from the south area of western Qaidam Basin,one of the largest saline lacustrine basins in China,the geochemical characteristics of aromatic hydrocarbons in oils were studied systematically in this paper.Among those constitutes,naphthalene(43% 59%),phenanthrene(12% 21%) and taromatic-sterane series(6% 28%) were the main ones of aromatic hydrocarbons.The ratio of aromatic hydrocarbon maturity parameter vs.saturated hydrocarbon maturity parameter C 29 20S/(20S+20R) shows that some aromatic hydrocarbon maturity parameters are not suitable for low-mature oils,including MPI,MNR,DNR,etc.Meanwhile,maturity parameters for dibenzothiophene and taromatic-sterane series are more appropriate for low maturity saline lacustrine crude oils.Based on the ratio of 4,6-DMDBT/1,4-DMDBT,the R c values are within the range of 0.59% 0.72%.However,the abundance of dibenzothiophene(DBT) is low,and the dibenzofuran(DBF) content is even lower,suggesting that the crude oils were formed in a saline lacustrine anaerobic environment.The high abundance of C 26 triaromatic steroid also indicates that the source material is brackish water-saline water with strong reducibility.     

成烃理论的发展：（1）未熟油及有机质成烃演化模式

The wide existence of immature oils throughout the world especially in China broke through the hydrocarbon generation theory through kerogen thermal degradation. Studies have shown that soluble and insoluble organic matter are organically connected in the sedimentary rock, both contributing to hydrocarbon generation. In the diagenesis,kerogen can not produce oils, so immature oils derive directly from the soluble lipids. Hydrocarbon generation process through kerogen thermal degradation takes place mainly in the early catagenesis(R o= 0.2% ～1.2%), and the oils generated are normal. In the late catagenesis, hydrocarbon generation comes into wet gas stage(R o=1.2%～2.0%), with pyrrobitumen degenerating into high mature light oils and oils cracking into gases. In this paper,the author presented a new generating hydrocarbon and evolutionary model with soluble and insoluble organic matter both contributing to the generation of hydrocarbon.     

威远、资阳震旦系干酪根与油裂解气的鉴别

根据威远、资阳震旦系气藏天然气组成、天然气碳同位素特征、储层包裹体的对比研究认为威远气田震旦系气藏的天然气主要来源于下寒武统泥岩。由于威远、资阳构造形成时间差异,威远为燕山期形成的构造,资阳为印支期形成,燕山消失,因此天然气的捕获时期不同,导致威远天然气主要是干酪根裂解气,次为油裂解气;而资阳主要是油裂解气     

有机酸盐热模拟产物中芳烃馏分特征及其地质意义

为了研究有机酸盐生烃演化特征,对有机酸盐进行了270℃、320℃、360℃、400℃和430℃一系列温度点的热模拟,实验结果表明,有机酸盐会大量转化为酮系列化合物,酮化合物最大产率阶段为320℃到360℃,其中360℃时产率最高,其转化率可达有机酸盐加入量的39%,400℃后产率急剧下降。这表明脂肪酸镁向酮系列化合物的最大转化温度段稍早或一致于有机质大量生烃阶段,但该类化合物对热较敏感,高温下不易保存,因此酮作为评价有机酸盐生烃贡献强度的指标只能适合于中—低温演化阶段的烃源岩。     

The role of minerals in the thermal alteration of organic matter--III. Generation of bitumen in laboratory experiments

A series of pyrolysis experiments, utilizing two different immature kerogens (from the Monterey and Green River Formations) mixed with common sedimentary minerals (calcite, illite, or Na-montmorillonite), was conducted to study the impact of the mineral matrix on the bitumen that was generated. Calcite has no significant influence on the thermal evolution of bitumen and also shows virtually no adsorption capacity for any of the pyrolysate. In contrast, montmorillonite and illite, to a lesser extent, alter bitumen during dry pyrolysis. Montmorillonite and illite also display strong adsorption capacities for the polar constituents of bitumen. By this process, hydrocarbons are substantially concentrated within the pyrolysate that is not strongly adsorbed on the clay matrices. The effects of the clay minerals are significantly reduced during hydrous pyrolysis. The strong adsorption capacities of montmorillonite and illite, as well as their thermocatalytic properties, may in part explain why light oils and gases are generated from certain argillaceous source-rock assemblages, whereas heavy immature oils are often derived from carbonate source rocks.     

现代松粉的热变质实验研究

本文通过现代松粉较大样品量的热模拟定量研究，认为松粉具有很大的生烃潜力，其特性接近于１类干酪根。以甲烷为主的伴生烃类气体最高产率达２４７ｍ３/ｔ。液态烃包括轻烃和抽提物，产率最高分别达６６．８ｋｇ/ｔ和９４．８ｋｇ/ｔ。受热变质的松粉，低温阶段主要是收缩变小，逐步出现裂隙和本体与气囊分离，３５０℃以上完全破碎。随温度升高松粉及碎片的颜色不断加深，主要调１５０℃以下为黄，２００℃～３００℃为棕，２５０℃～４５０℃为棕黑，５００℃以上为黑。色度指数和镜质组反射率值也随温度升高而增大。     

东营凹陷盐湖相天然气生成的热模拟试验

东营凹陷民丰地区沙四段是典型的盐湖相沉积,也是本区重要的烃源灶和天然气产层。为了研究不同盐类物质与烃源岩在高成熟阶段的相互作用,采用高压釜封闭体系模拟了东营凹陷盐湖相烃源岩的天然气生成过程。结果表明：碳酸盐、硫酸盐、氯化盐对烃源岩热解生成天然气有强催化作用,同烃源岩热解相比,550℃时气态烃产率分别增加了35%、77%和46%。在4组热模拟气的气态烃组成及热模拟气与民丰地区天然气的轻烃组分比较中发现,上述蒸发盐类不仅改变了气态烃产物中各单组分化合物的生成路径,影响了气态烃产物的组成,而且在盐类物质参与作用下,烃源岩热解的气态烃组成与民丰地区天然气更接近。     

中国古生界海相烃源岩生烃潜力评价标准与方法

中国古生界海相高、过成熟烃源岩原始生烃潜力评价问题是一个没有解决的老问题,至今没有可靠的评价方法与统一评价标准。低成熟元古宇—古生界海相泥岩/页岩与碳酸盐岩地球化学分析揭示,由于有机质组成不同,不同时代烃源岩的有机碳含量与热解生烃潜力之间存在着不同的线性关系。按照岩石热解生烃潜力来衡量,泥岩/页岩与碳酸盐岩作为有效烃源岩的有机质丰度下限没有本质区别,其有机碳含量必须大于0.5%;对于元古宇-下古生界海相烃源岩,达到中等生烃潜力的有机碳含量必须大于0.75%,好烃源岩的有机碳含量必须大于1.5%,很好烃源岩的有机碳含量大于2%,有机碳含量大于4%的属于极好的烃源岩;上古生界海相泥岩各级烃源岩相应的有机碳界线值高于下古生界泥岩。按照低成熟元古宇—古生界烃源岩有机碳含量与热解生烃潜力之间的关系方程,由有机碳含量基本上可以定量评价高、过成熟的元古宇—古生界烃源岩的原始生烃潜力。     

Natural background of hydrocarbon gases (C1–C5) in the waters of the Kara Sea

The distributions of methane and hydrocarbons (HC) C2+ throughout the vertical section of the water mass and sediments of the Kara Sea and the estuaries of the Ob and Yenisei rivers were examine during expeditions aboard the R/V “Akademik Boris Petrov” in 1997–2002. Data obtained during the expeditions and extensive information provided by the complex study of the carbon cycle in the aquatic area were used to analyze the genesis of hydrocarbon gases in marine water. The example of particulate matter was used to demonstrate that hydrocarbon gases of the composition C2–C5 contained in seawater are genetically related to aquatic organic matter (OM), regardless of seawater salinity. The hydrocarbon complex is dominated (80%) by higher C4–C5 homologues. The concentration of C4–C5 hydrocarbons in the estuarine fresh waters is comparable with the high methane concentration (2–3 μl/l), drastically decreases in the zone of water mixing, and then rapidly increases to values several times higher than the methane concentration in seawater outside the outer boundary of the sedimentation depocenter of riverine particulate matter. A direct correlation was established for the concentration of the C4 + C5 homologues with the OM of the water mass, and the leading role was demonstrated to be played by labile OM of the autochthonous biomass (marine phytoplankton) in the genesis of higher hydrocarbon gases (alkenes, alkanes, and isoalkanes) during the early diagenetic stage of OM transformations in water. Along with the biomass of phytoplankton, a significant role in the genesis of C2–C3 hydrocarbons is played by destruction products of terrigenous OM. The destruction of OM and generation of gaseous hydrocarbons, including methane, are restricted to the pycnocline and the water-sediment interface. The absolute predominance of the sum of the C4 + C5 homologues in the hydrocarbon C2+ gases and the presence of unsaturated C2–C4 hydrocarbons are typical of the natural background of hydrocarbons of the Kara Sea water mass.     

Kinetic Modeling the Formation of Low-mature Gases and Analysis of the Possibility to Be Accumulated

At present, shallow gases have received much attention due to low cost in exploration and production. Low-mature gases, as one significant origin to shallow gas, turns to be an important research topic. The present understanding of low-mature gases is confined within some geological cases, and few laboratory studies have been reported. Therefore, the potential and characters of low- mature gases are not clear up to now. Here, two premature samples （one coal and the other shale） were pyrolyzed in a gold confined system. The gaseous components including hydrocarbon gases and non-hydrocarbon gases were analyzed. Based on kinetic modeling, the formation of low-mature gases was modeled. The results showed that during low mature stage, about 178 mL/gTOC gas was generated from the shale and 100 mL/gTOC from the coal. Two third to three fourth of the generated gases are non-hydrocarbon gases such as H2S and CO2. The total yields of C1-5 for the two samples are almost the same, 30-40 mL/gTOC, but individual gaseous hydrocarbon is different. The shale has much lower C1 but higher C2-5, whereas the coal has higher C1 but lower C2-5. Hydrocarbon gases formed during low-mature stage are very wet. The stable carbon isotope ratios of methane range from -40‰ to -50‰ （PDB）, in good consistence with empiric criterion for low-mature gases summed up by the previous researchers. The generation characters suggest that the low-mature gases could be accumulated to form an economic gas reservoir, but most of them occur only as associated gases.     

Geochemical Characteristics of Crude Oils from Zao-V Oil Measures in Shenjiapu Oilfield

The geochemical characteristics of crude oils from Zao-V oil measures in the Shen-jiapu oilfield are systematically described in terms of the fractional composition of crude oils, GC characteristics of saturated hydrocarbon fraction of crude oils and the characteristics of their bio-markers. The deposifional environment, type and evolution of the biological source are also discussed. All pieces of evidence such as low saturated hydrocarbon fraction, high resin and asphalt, high isoprenoid alkane, weak odd-carbon number predominance ( CPI ranging from 1.23 to 1,29, OEP ranging from 1.14 to 1.16) and low sterane and terpane maturity parameters show these crude oils are immature oils. Low Pr/Ph ratios (0.66 -0.88) and high gammacer-ante/C31 hopane ratios ( 0.59 - 0.86 ) indicate the source rocks were formed in a slightly saline to brackish reducing lake depositional environment. Gas chromatographic characteristics of the saturated hydrocarbon fraction and the predominance of C30 hopane in terpane series and C29 sterane in sterane series indicate the biological source of the crude oils is composed mainly of bacterial and algal organic matter, and some algae are perhaps the main contributor of organic matter to the source rocks.     

Biological marker characteristics of oils and asphalts from carbonate source rocks in a rapidly subsiding graben,Dead Sea,Israel

A detailed GC/MS study of biological marker compounds in the saturated and aromatic hydrocarbon fractions of oils and asphalts from the Dead Sea area, Israel, provided decisive information to the solution of a long-lasting controversy by showing that the asphalts are products of early generation in an immature stage from the same type of carbonate source rock which generated more mature oils. The asphalts are not biodegraded residues of the oils.Oils from six different wells, and asphalts from wells, outcrops, and a floating block from the Dead Sea all have very similar sterane and triterpane patterns. They all lack rearranged steranes (diasteranes) indicating a carbonate source matrix and compare reasonably well with a sample of Upper Cretaceous bituminous chalk from Nebi Musa. The main difference between the oils and the asphalts is a significantly higher triaromatic to mono- plus triaromatic steroid hydrocarbon ratio in the former. This is explained as a result of rapid subsidence and heating of their source rock close to the deep parts of the Dead Sea graben. The oils thus were generated in the more deeply buried source rock blocks under the graben fill, whereas the asphalts either originate from an immature source rock section closer to the graben rims or represent an earlier phase of generation and expulsion.This study also provides general information on the evolution of biological markers in carbonate source rocks. Low-activation-energy processes, like isomerisation of steranes, appear to occur much faster at low temperatures than in shales. The high sulfur content and less cross-linking of the biogenic organic matter into a complex kerogen structure are suggested to be responsible for this. Care should be taken when using only sterane isomerisation to assess the maturity of hydrocarbons from carbonate rocks and of carbonate-derived oils.     

川东北元坝地区雷口坡组天然气来源与成藏分析

四川盆地雷口坡组已成为一个重要的天然气勘探目的层,有关雷口坡组天然气的来源以及雷口坡组是否具有生气潜力还存在争议。研究表明雷口坡组泥质白云岩与泥质灰岩有机碳含量平均达到0.72%,具有较高的生烃潜力。雷口坡组天然气以烃类气体为主,干燥系数为0.99。不同于其他海相层系天然气,其CO₂和N₂含量较少,总量<10%,仅含微量的H₂S;它们的甲烷碳同位素相对较重(-31.5‰~-36.3‰),而乙烷碳同位素较轻,基本上都小于-28‰(-27.7‰~-36.6‰),且部分气呈δ¹³C₁>δ¹³C₂反序分布,属高-过成熟海相油型气。其烷烃气系列碳同位素组成既不同于上覆的须家河组陆相天然气,也有异于下伏飞仙关组-长兴组海相气,具有不同的气源,经与雷口坡组烃源岩轻烃组成的对比,认为其气源主要来自本层位。成藏条件分析表明,雷口坡组天然气的富集主要受烃源岩和储层的发育及分布控制,只有紧邻烃源岩发育的浅滩相白云岩/裂缝型灰岩构成的“岩性圈闭”才能形成天然气的聚集。