碳酸盐岩储层原油裂解过程中的钙、硫分子地球化学研究—同步辐射XANES技术的应用

为了研究碳酸盐岩储层原油裂解过程中硫、钙元素赋存状态的变化,采集塔河油田TK772井奥陶系鹰山组产层的原油,通过半开放实验体系"地层孔隙热压生排烃模拟仪"开展仿真地层条件的成气模拟实验,利用同步辐射X射线吸收近边结物(XANES)技术对固体产物中的硫、钙元素的化学赋存状态进行精确检测。结果表明,原油直接裂解(原油+灰岩实验(系列1))固体产物中含硫化合物以噻吩类和硫酸钙为主,是原油裂解过程中部分噻吩类物质被氧化的结果;含钙化合物以碳酸钙为主。有溶解硫酸盐存在的原油裂解(原油+灰岩+硫酸镁实验(系列2))固体产物中含硫化合物以硫酸钙为主,噻吩类为辅,可能是溶解硫酸盐(硫酸镁)的加入、硫酸盐热化学还原反应(TSR)和溶蚀-沉淀作用共同作用的结果。系列2中伴随着温压的升高,H2S的生成和硫酸钙相对百分含量增加,指示原油裂解过程中发生了硫酸盐热化学还原反应(TSR);硫酸钙的生成和富集表明,TSR过程产生的酸性流体可以对碳酸盐岩储层产生明显的溶蚀作用,同时可能会生成次生膏盐。     

加热时间对生烃模拟过程的影响

通过 36 0℃、不同模拟时间下生油岩生烃演化过程的分析 ,探讨了加热时间对模拟结果的影响。发现延长加热时间 ,气体产率将不断增加 ,其中总烃气增加幅度大于非烃气体。同时丁烷、戊烷和 C+ 5烃类含量在时间很长时发生裂解生成更小分子的甲烷、乙烷和丙烷。随模拟时间的延长 ,非烃气中除氢气含量随加热时间延长而增加外 ,其余非烃气包括二氧化碳、氮气、氧气和一氧化碳等气体和液态产物产率降低 ,干酪根元素组成中 x( H) /x( C)值和 x( O) /x( C)值不断降低 ,而镜质体反射率变化不明显。     

储层介质环境对原油裂解生气影响的实验研究

采用封闭黄金管高压釜体系,在恒温(365℃)、恒压(50 MPa)条件下模拟不同储层介质环境下原油的裂解生气过程。实验结果表明:(1)在模拟实验条件下,水、矿物基质对原油裂解具有促进作用,使得气体产率有所提高,其中气态烃产率大约提高1倍,H2、CO2产率也有所提高;(2)硫酸镁溶液的存在可导致原油热解体系发生明显的硫酸盐热化学还原反应(TSR),产生大量H2S气体,同时烃类气体产率也有大幅提高,气体干燥系数明显增大;气体碳同位素数据表明TSR反应使甲烷、乙烷、丙烷相对富集13C;(3)一定量氯化钠溶液的存在会促进TSR反应,使得气态烃与非烃产率明显提高,同时造成烃类气体碳同位素组成的偏重(富集13C),乙烷的增重尤其明显,最大变化可达4‰。因此,储层介质环境对原油裂解具有显著的影响,在利用气体化学和同位素组成对原油裂解气进行研究时需要考虑储层介质环境可能存在的影响。     

两种温压体系下烃源岩生烃演化特征对比及其深层油气地质意义

利用3种有机质类型的海相烃源岩,分别在温压共控模拟和常规高压釜模拟两种温压体系下开展生烃模拟实验。在系统对比两种模拟方式产物产率、有机地球化学特征基础之上,分析了静岩压力和流体压力、水的性质与相态对烃源岩生烃过程与生烃机理的影响,探讨了实验结果在深层油气勘探中的地质意义。实验结果对比表明,高静岩压力和流体压力以及高温压缩态水的存在对有机质生烃演化具有明显控制作用,主要表现在以下几点:(1)有机质镜质组反射率受到"抑制",成熟阶段原油生成被延迟,高过成熟阶段延缓原油向烃气转化;(2)原油和原油裂解气产率增加,干酪根裂解烃气、CO_2和H_2非烃气产率降低;(3)原油产物中非烃和沥青质组分含量增加,烃气产物干燥系数相对较低、碳同位素值更偏负;(4)促进了干酪根"解聚型"生成油气方式的发生,抑制了"官能团脱除型"生成油气方式的发生。实验结果为深层油气资源评价、勘探深度下限厘定、烃类相态预测提供了有价值的信息。     

中国典型海相富有机质页岩的生气机理

目前页岩生烃的评价体系主要停留在静态条件下,忽略了成烃的动态过程,不能正确评价页岩原始的生烃潜力.采用生烃动力学模拟实验方法,分别对一个相对低成熟的典型海相富有机质页岩及其干酪根样品开展封闭体系和半开放体系下的人工熟化,并对熟化后的两个系列样品进行黄金管生气动力学模拟实验.对裂解产物中气态烃化合物、轻烃类化合物以及碳同位素开展了定量分析,结果表明,甲烷生成过程被划分为4个阶段,即生油（小于1.0% EayR_o）、凝析油生成（1.0%~1.% EayR_o）、湿气生成（1.%~2.2% EayR_o）和干气生成阶段（大于2.2% EayR_o）;页岩中甲烷的最大产率主要来自干酪根的初次裂解（占22.7%）、可排沥青（占7.6%）和残余沥青（占19.6%）的二次裂解;经过早期排烃作用的页岩样品仍有大量的可溶沥青,在高-过成熟阶段其可以与干酪根、不可溶沥青相互作用,成为晚期主要的页岩生气母质.      

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%.      

煤岩、泥岩密闭体系下热解产物特征及动力学分析

通过密闭体系热模拟实验考察了煤岩和泥岩产物产率及动力学特征,结果表明高温阶段甲烷的来源除了重烃气的裂解外,还有有机质直接裂解的贡献。泥岩有机质在初次裂解过程中易于生甲烷的组分较少且热稳定性要高,煤岩有机质在初次裂解过程中易于生甲烷的组分相对较多且稳定性较弱。煤岩在低温阶段热解的液态烃中正构烷烃通过环化和芳香化作用与沥青...     

金沙岩孔灯影组古油藏沥青有机地球化学特征及油源分析

为详细研究华南海相震旦系古油藏沥青来源,对金沙岩孔灯影组古油藏进行了系统解剖.古油藏沥青主要富集于灯影组上部砂屑白云岩、鲕粒白云岩及藻白云岩中,野外采集固体沥青呈块状富集,质地坚硬,有污手性,沥青主要赋存在白云岩晶间孔、铸模孔以及溶洞内,呈黑色固态物质产出,镜下观察沥青具镶嵌状结构特征.含沥青白云岩有机碳含量0.52%~1.89%,表明其较高的有机质含量.沥青受高温裂解及地表水淋滤氧化作用,氯仿沥青“A”及热解潜量较低,沥青有机碳同位素值为–33.22‰~–32.06‰, V/(V+Ni)比值较高为0.75~0.94,沥青反射率2.95%~3.86%,双反射明显,热演化程度高,大部分样品 H/C 比值小于0.5.综合研究表明,沥青在地质历史中曾经受了高温热演化作用,为原油高温裂解焦沥青.通过生物标志物、有机碳同位素、单体烃同位素及 V/(V+Ni)比值对比分析认为沥青来源于下寒武统牛蹄塘组黑色岩系.     

近临界特性的地层水及其对烃源岩生排烃过程的影响

研究利用特制的地层孔隙热压模拟实验装置, 开展了模拟地层孔隙空间高压液态水热体系烃源岩生排烃模拟实验.模拟实验施加的流体压力为38±2 MPa, 温度为290~390 ℃.模拟实验结果显示了有关高压液态水及其与之相联系的流体压力和孔隙空间等因素对烃源岩生排烃影响作用的一些重要现象, 实验发现高压液态水介质条件有利于液态油的生成和保存, 不利于液态油向气态烃的转化, 而且干酪根的生烃潜力和排油效率有一定的提高.这些新的实验现象可能主要与近临界特性的高压液态地层水的作用有关, 进一步推断近临界特性的高压液态水参与干酪根向油气的转化反应, 增加了水对油气的溶解能力.在地下实际烃源岩生排烃的温压(100~200 ℃, 30~120 MPa)条件下, 岩石孔隙中的地层水是一种相对低温高压压缩液态水, 这种地层水可能具有近临界特性, 对烃源岩生排烃过程有重要影响.但目前对这种现象的机理和石油地质意义还知之较少.因此, 加强高压地层水近临界条件下烃源岩生排烃热压模拟实验研究, 对进一步深入理解地层条件下的近临界水介质、流体压力、孔隙空间因素对生排烃过程的影响, 深化烃源岩生排烃机理的探讨, 建立地质尺度上的烃源岩生排烃动力学模型, 都具有重要的理论和实际意义.      

非烃和沥青质热模拟生烃研究

为弄清楚非烃＋沥青质热演化过程中的生烃情况，对未熟非烃＋沥青质进行了低温模拟生烃实验，实验结果表明非烃＋沥青质在低温条件下（＜250℃）生成烃类气体量很少，主要以生成液态烃为主，液态烃转化率最高可达388mg/g，所生成的液态烃表现出明显的奇碳优势，为未熟－低熟油。原始母质类型不同的非烃＋沥青质模拟产物特征有所不同。非烃＋沥青质对未熟－低熟油的生成有重要意义。     

Energy Field Adjustment and Hydrocarbon Phase Evolution in Sinian-Lower Paleozoic,Sichuan Basin

The Sinian-Lower Paleozoic (also called the lower association) in Sichuan (四川) basin has undergone geologic evolution for several hundred million years.The subsidence history of the Sinian-Lower Paleozoic can be divided into four stages:the stable subsidence during Cambrian and Silurian; the uplift and denudation during Devonian and Carboniferous; the subsidence (main process)during Permian to Late Cretaceous; and the rapid uplift and denudation since Late Cretaceous.The later two stages could be regarded as critical factors for the development of oil and gas in the lower association.The evolution of energy field such as temperature,pressure,and hydrocarbon phase in the lower association during the deep burial and uplift in the third stage might be induced as follows:(1)super-high pressure was developed during oil-cracking,previous super-high pressure was sustained,or changed as normal pressure during late uplift; (2) temperature increased with deep burial during persistent subsidence and decreased during uplift in late stage; (3) as a response to the change of the energy field,hydrocarbon phase experienced a series of changes such as organic material (solid),oil (liquid),oil-cracking gas (gaseous) + bitumen (solid) + abnormal high pressure,gas cap gas with super-high pressure (gaseous) + bitumen (solid) + water soluble gas (liquid),and gas in pool (gaseous) + water soluble gas (liquid) + bitumen (solid).The restoration of hydrocarbon phase evolution is of important value for the exploration of natural gas in the Sinian-Lower Paleozoic in Sichuan basin.     

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。     

矿物在油气形成过程中的作用

模拟实验结果表明,矿物组成对煤岩样品的模拟实验结果具有很大的影响,不同的矿物以及同一种矿物在不同的有机质热演化阶段,对有机质形成石油和天然气的过程均具有非常明显的影响:高岭土矿物在高温热演化阶段对有机质形成气态烃的过程具有一定的催化能力;碳酸钙（CaCO3）在中—低热演化阶段能抑制气态物质的形成,而在较高的热演化阶段则对煤生成气态物质的过程具有一定的催化作用;四氧化三铁（Fe3O4）在主要的模拟实验阶段对煤生成气态物质的过程均具有一定的催化作用;硫化亚铁（FeS）在低温热演化阶段对天然气的形成具有一定的抑制作用,而在高温热演化阶段则对天然气的形成具有较明显的催化作用;元素硫（S）在不同的热演化阶段对天然气的形成过程均具有非常明显的催化作用。矿物介质不仅对气态产物的产率有比较明显的影响,而且对液态产物的产率也有较明显的影响。模拟实验结果表明:高岭土和四氧化三铁（Fe3O4）在中、低温模拟实验阶段对“氯仿沥青A”的形成具有较明显的催化作用;硫化亚铁（FeS）在整个模拟实验的全过程中对“氯仿沥青A”的形成均具有明显的催化作用;碳酸钙（CaCO3）矿物对“氯仿沥青A”的形成具有明显的抑制作用;元素硫（S）对“氯仿沥青A”的形成具有非常明显的催化作用。     

Three Episodes of Hydrocarbon Generation and Accumulation of Marine Carbonate Strata in Eastern Sichuan Basin, China

It is concluded that there are three hydrocarbon generation and accumulation processes in northeastern Sichuan on the basis of the characteristics of solid bitumen, gas-light oils-heavy oils, homogenization temperature of fluid inclusions and diagenesis for beach- and reef-facies dolomite gas- bearing reservoirs in the Puguang Gas Field, northeastern Sichuan Basin, southern China. The first hydrocarbon generation and accumulation episode occurred in the Indosinian movement （late Middle Triassic）. The sapropelic source rocks of the O3w （Upper Ordovician Wufeng Formation）-S1l （Lower Silurian Longmaxi Formation） were buried at depths of 2500 m to 3000 m with the paleogeothermal temperature ranging from 70℃ to 95℃, which yielded heavy oil with lower maturity. At the same time, intercrystalline pores, framework pores and corrosion caused by organic acid were formed within the organic reef facies of P2ch （Upper Permian Changxing Formation）. And the first stage of hydrocarbon reservoir occurred, the level of surface porosity of residual solid bitumen {solid bitumen/ （solid bitumen ＋ residual porosity）} was higher than 60%. The second episode occurred during the Middle Yanshanian movement （late Middle Jurassic）. During that period, the mixed organic source rocks were deposited in an intra-platform sag during the Permian and sapropelic source rocks of O3w-S1l experienced a peak stage of crude oil or light oil and gas generation because they were buried at depths of 3500 m to 6800 m with paleogeothermal temperatures of 96-168℃. At that time, the level of surface porosity of residual solid bitumen of the T1f shoal facies reservoirs was between 25% and 35%, and the homogenization temperatures of the first and second stages of fluid inclusions varied from 100℃ to 150℃. The third episode occurred during the Late Yanshanian （Late Cretaceous） to the Himalayan movement. The hydrocarbon reservoirs formed during the T1f and P2ch had the deepest burial of 7700 m to 8700 m and paleogeotemperatu     

四川盆地东部长兴组--飞仙关组气藏地球化学特征及气源探讨

四川盆地上二叠统长兴组生物礁和下三叠统飞仙关组鲕滩是“九五”期间的勘探重点,通过对长兴组-飞仙关组气藏的烃源岩、储层沥青和天然气的地球化学研究,确认了上二叠统的滨岸煤系泥岩和海槽相碳酸盐岩为主要烃源岩,长兴组-飞仙关组气藏天然气主要来源于下伏的上二叠统烃源岩,天然气以垂相运移为主,飞仙关组部分气藏天然气中硫化氢含量较高与储层中膏岩层的分布和热硫酸盐还原作用有关,上述这些特征与沉积相带密切相关。     

Formation of Natural Bitumen and its Implication for Oil/gas Prospect in Dabashan Foreland

Natural bitumen is the evolutionary residue of hydrocarbon of sedimentary organic matter. Several kinds of bitumen with different occurrences, including bitumen in source rock, migration bitumen filled in fault, oil-bed bitumen and paleo-reservoir bitumen, are distributed widely in the Dabashan foreland. These kinds of bitumen represent the process of oil/gas formation, migration and accumulation in the region. Bitumen in source rock filled in fractures and stylolite and experienced deformation simultaneously together with source rock themselves. It indicated that oil/gas generation and expelling from source rock occurred under normal buried thermal conditions during prototype basin evolution stages prior to orogeny. Occurrences of bitumen in source rock indicated that paleo-reservoir formation conditions existed in the Dabashan foreland. Migration bitumen being widespread in the fault revealed that the fault was the main channel for oil/gas migration, which occurred synchronously with Jurassic foreland deformation. Oil-bed bitumen was the kind of pyrolysis bitumen that distributed in solution pores of reservoir rock in the Dabashan foreland depression, the northeastern Sichuan Basin. Geochemistry of oil-bed bitumen indicated that natural gas that accumulated in the Dabashan foreland depression formed from liquid hydrocarbon by pyrolysis process. However, paleo-reservior bitumen in the Dabashan forleland was the kind of degradation bitumen that formed from liquid hydrocarbon within the paleo-reservior by oxidation, alteration and other secondary changes due to paleo-reservior damage during tectonics in the Dabashan foreland. In combination with the tectonic evolution of the Dabashan foreland, it is proposed that the oil/gas generated, migrated and accumulated to form the paleo-reservoir during the Triassic Indosinian tectonic movement. Jurassic collision orogeny, the Yanshan tectonic movement, led to intracontinental orogeny of the Dabashan area accompanied by geofluid expelling and paleo-reservoir damage in the Dabashan foreland. The present work proposed that there is liquid hydrocarbon exploration potential in the Dabashan foreland, while there are prospects for the existence of natural gas in the Dabashan foreland depression.     

甲烷和固态硫酸钙的热化学还原反应模拟实验初步研究

碳酸盐岩地层中常伴有硫酸盐岩的沉积，在一定的温度和压力条件下，干酪根热降解生成的气态烃与硫酸盐岩接触后发生热化学还原反应(简称为TSR反应)，使气态烃消失，这可能是造成生气死亡线的主要原因之一。本文对CH4-CaSO4热化学还原反应的热力学问题进行了探讨，发现该反应能够自发进行，而且升高温度对反应有利。利用高温高压模拟装置对CH4-CaSO4反应体系进行了初步的模拟实验研究，通过微库仑、气相色谱和傅里叶变换红外光谱(FT-IR)等分析手段对实验结果进行了进一步验证。结果表明，甲烷和固态硫酸钙能够发生热化学还原反应，生成硫化氢、碳酸钙和水。最后，将CH4-CaSO4反应体系同国内外的研究工作进行了对比，认为本实验研究能够更好地补充和完善TSR反应体系，解释地质条件下工业气藏的死亡线问题。     

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.     

川东北飞仙关组储层固体沥青地球化学特征及其气源指示意义

运用有机岩石学、有机地球化学、催化加氢热解、GC—IRMS等方法和技术,深入研究了川东北飞仙关组储层固体沥青及可能烃源岩的地球化学特征。研究认为,飞仙关组储层固体沥青反射率高,双反射明显,为非均质结构储层焦沥青;在碳酸盐岩储层的各种孔隙中,呈脉状、球粒状、角片状或块状等他形充填,具有中间相结构和镶嵌状结构特征,反映其高温热变质成因;元素组成有S/C高、H/C低的特点,其固体碳同位素组成与长兴组烃源岩干酪根相似。储层固体沥青的可能烃源岩发育于还原—弱氧化咸水沉积环境,有机质来源于水生藻类;氯仿沥青“A”饱和烃甾萜类生物标志物对比表明,上二叠长兴组烃源岩是主要来源,飞仙关组、下志留统烃源岩亦有贡献;催化加氢产物饱和烃及其正构烷烃单体碳同位素组成显示,坡2井飞仙关组储层固体沥青与罐5井飞仙关组烃源岩具有明显的亲缘关系,这也可作为飞仙关组海槽相烃源岩对飞仙关组气藏有贡献的佐证。