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1.
运用镜质组反射率、袍子体荧光参数、生物标志物参数详细研究了三塘湖盆地中生界烃源岩的有机质热演化特征及演化阶段。研究表明镜质组反射率是该区有机质热汪化最可靠听成熟度参数,孢子体荧光参数是重要的热演化指标,生物标志物参数是有效的热演化指标。三塘湖盆地有机质总体热演化水平较低,且在横向和纵向上存在明显的差异。该区的有机质热演化具有明显的阶段性,运用成熟度参数将其划分为未成熟和成熟两个阶段。  相似文献   

2.
西藏中部伦坡拉盆地古近系沉积有机质特征及意义   总被引:2,自引:0,他引:2  
西藏中部班公湖-怒江缝合带之上发育一些新生代陆相沉积盆地.与西藏海相沉积盆地相比,这些陆相沉积盆地沉积有机质丰度高、类型好及热演化程度中等,具有很好的油气勘探前景.伦坡拉盆地是其中的代表并且是目前西藏唯一的获得工业油流的盆地.本文对伦坡拉盆地古近系丁青湖组与牛堡组实测剖面有机岩石学及有机地球化学分析研究表明:丁青湖组页岩沉积于半深湖-深湖环境,有机碳含量在2.84%~6.92%之间,有机质类型为Ⅰ型和Ⅱ1型,母质主要来源于藻类及少量高等植物的输入,有机质镜质组反射率(Ro)在0.46%~0.63%之间;牛堡组泥岩和页岩为滨浅湖相沉积,有机碳含量在0.25%~5.99%之间,有机质类型为Ⅰ型和Ⅱ 1型,母质主要来源于藻类及极少量高等植物的输入,镜质组反射率(Кo)在0.49%~0.66%之间;生物标志化合物组成分布特征显示丁青湖和牛堡组沉积于分层的水体且底部水体盐度较高.  相似文献   

3.
盆地有机质的演化研究对认识盆山耦合关系具有十分重要的意义。盆地有机质及其演化产物主要受到温度、时问、应力等条件的影响。借助盆地中有机质的镜质体反射率、有机流体包裹体、有机地球化学指标等参数可分析建立盆山构造地层体系和统一的地下流体温度、压力场及构造应力场,最终反演整个盆山的耦合历程。  相似文献   

4.
沉积盆地内热流体活动过程实际上是热流体聚集与散失的动平衡过程.热流体活动必然导致温度和压力以及化学条件的改变,尽管如此,沉积盆地内热流体活动的示踪难度较大.通过对莺歌海盆地典型实例的剖析,认为较为有效的方法就是通过热流体活动中的温度效应进行示踪研究.其中较为有效的参数有伊-蒙矿物的转换、镜质体反射率和有机物热解指标以及流体包裹体等.这些参数的不同形式的异常均指示了来自深部的热流体的活动.  相似文献   

5.
根据对秦岭泥盆纪沉积盆地的构造成盆 -后期构造变形特征研究 ,秦岭造山带泥盆纪热水沉积成矿盆地中构造 -热流体地质事件可初步厘定如下 :1中泥盆世伸展构造成盆 -热水同生沉积成矿事件 (D1)。2晚泥盆世 -石炭纪伸展变形 -深源热流体叠加事件 (D2 )。3印支期挤压收缩变形 -热改造事件 (D3 )。 4燕山期逆冲推覆构造改造 -深源热流体叠加及脆性变形事件 (D4 )。 5喜玛拉雅山期脆性变形 (D5)。从盆地热状态及热演化研究角度看 ,盆地内充填地层体中有机质及矿物可以记录热状态及热演化历史 ,利用盆地内充填地层体中有机质及矿物温度计可以反演盆地内充填地层体形成时盆地热状态和盆地底部热流。认为热水沉积成矿盆地热状态及热演化主要研究方法有主要矿物流体包裹体测温、镜质体反射率 (R0 )法、氧同位素地质温度计法等。  相似文献   

6.
沉积有机质二次生烃有机岩石学特征   总被引:5,自引:0,他引:5       下载免费PDF全文
采用自然演化系列与预热残渣热模拟系列相结合的方式,对异常地热场条件下的沉积有机质二次生烃有机岩石学特征进行探讨,表明沉积有机质二次生烃有机组份及其组合不同于一次连续演化生烃,除具有正常的显微组份外,还具有体现二次演化特征的热变组份和热变次生组份。热变组份保持原来的组份结构,但光性出现各向异性,包括热变镜质组、热变壳质组和热变惰质组;热变次生组份具有不同于泥炭化时期所成的显微组份结构特征,往往具有较为强烈的光学各向异性。沉积有机质二次演化显微组份组合特征与起始成熟度密切相关,低熟和高熟沉积有机质显微组份光性和结构改变小,成熟沉积有机质改变显著。以起始成熟度为根据,以显微组份成因、光学性质和结构构造为依托,对沉积有机质二次生烃显微组份进行科学分类。探讨了热变次生显微组份的可能成因,指出中间相的产生和发展是热变次生显微组份形成与否的关键因素。  相似文献   

7.
压力对有机质演化的影响长期以来争论不断,共有3种不同意见:压力对有机质演化没有影响,压力促进有机质的演化,压力抑制有机质的演化。通过对前人所做实验的实验设备、实验样品及实验结果的分析对比发现:不同实验结果主要是由于不同实验条件引起的,特别是实验系统和加压方式的不同,对实验结果影响最大,所代表的地质意义也不同。综合分析结果表明,当压力的增加表现为沉积有机质受到的有效应力增加时可以促进有机质生烃;当压力的增加表现为孔隙流体压力增加时,有机质生烃过程将受到抑制;另外,这两种情况都可能使干酪根的镜质组反射率降低,易使人得出压力增加抑制有机质演化的结论。进一步对压力影响有机质演化的成因机制进行了分析,发现在有机质演化的不同阶段因异常压力的增压机制不同,压力在有机质演化过程中所表现出来的作用也有差异。  相似文献   

8.
热流体活动示踪标志及其地质意义   总被引:6,自引:1,他引:5       下载免费PDF全文
解习农  董伟良 《地球科学》1999,24(2):183-188
沉只盆地内热流体活动过程实际上是热流体聚集与散失的动平衡过程,热流体活动必然导致温度和压力以及化学条件的改变,尽管如此,沉积盆地内流体活动的示踪难度较大,通过经盆地典型实例的剖析,认为较为有效的方法就是通过热流体活动中的温度效应进行示踪研究,其中较为有交的参数有伊-蒙矿物的转换、镜质体反射率和有机物热解指标以及流登攀民裹体等,这些参数的不同形式异常均指示了来自深部的热流体的活动。  相似文献   

9.
镜质组反射率与沉积盆地古地温分析   总被引:3,自引:1,他引:3  
汤达祯 《地学前缘》1995,2(4):181-188
在地质研究与资源勘探中,特别是针对油气生成、运移和保存有关的地热过程分析,镜质组反射率(R)已被广泛地应用于沉积盆地古地温的确定。本文从R增值的反应动力学、R-古地温-受热时间模拟计算、流体扰动对流型热体系中的R性征及R古地温分析技术扩展等方面,概括地总结讨论了有关应用现状与理论进展。由于沉积有机质构成及其热反应作用的复杂性,过分简单地将R与地温值对应的做法已被否定,代之以地质、地球热力学与反应动力学的综合分析。不同源岩中R增值与热能关系的确定,温度-时间计算方法的改进、异常热背景如对流型热体制的分析以及低成熟与镜质组缺失条件下成熟度参数的R标定等,将是今后急待解决的主要问题。  相似文献   

10.
准噶尔盆地热历史   总被引:19,自引:0,他引:19  
准噶尔盆地从石炭一二叠纪的“热盆”(古地温梯度0.05-0.07℃/m)演变成新生代典型的“冷盆”(地温梯度0.02-0.023℃/m),使盆地两套主要烃源岩:二叠系和侏罗系烃源岩热演化程度(成熟度)具有明显的差异。二叠系径源岩成熟度普遍很高,大部分达到过成熟阶段;而侏罗系烃源岩成熟度则很低,即使埋深超过5000m,实测镜质组反射率R°%仅为0.5-0.6,相当于生油初期(低成熟)阶段。通过应用Waples模型和Sweeney-Burnham模型两种方法对盆地13口深井进行古地温梯度拟合计算表明:对于热演化过程主要发生在白垩纪之前,高地温梯度背景下的8口深井,烃源岩热演化受压力的影响小,成熟度相对较高;而对于热演化过程主要发生在白垩纪之后、低地温梯度背景下的5口井,烃源岩热演化受压力的影响较大,成熟度异常偏低,实测镜质组反射率低于用Waples模型和Sweeney-Burnham模型计算的镜质组反射率。  相似文献   

11.
Based on the tested data of pressure and vitrinite reflectance of some wells in sedimentary basins, abnormal high pressure is regarded as not the only factor to retard the increase of vitrinite reflectance (R o). Apart from the types of the organic matter, the physical environment (temperature and pressure) and chemical environment (fluid composition and inorganic elements) will result in the abnormal vitrinite reflectance values in the sedimentary basins. This paper tested trace elements and vitrinite reflectance data from the the abnormal high pressure and normal pressure strata profiles, respectively, and found that the acidic and lower salinity starta are favorable for the increase of R o. By discussing the corresponding relationship between the contents of some trace elements in the mudstone and the vitrinite reflectance values, the typical trace elements were found to suppress and/or catalyze the vitrinite reflectance of organic matter, while the elements of Ca, Mn, Sr, B, Ba and P may result in the retardation of R o. However, elements of Fe, Co, Zn, Ni and Rb may catalyze the organic matter maturation. This study is conductive to the organic maturation correction, oil and gas assessment and thermal history reconstruction by the paleothermometry. Translated from Acta Geologica Sinica, 2006, 80(11): 1760–1769 [译自: 地质学报]  相似文献   

12.
Levels of organic maturity of Mesozoic and Tertiary sequences outcropping in the Central Apennines have been established, using vitrinite reflectance techniques, the Thermal Alteration Index and fluorescence colours of organic matter dispersed in sediments. These results provide new constraints throughout the Meso-Cenozoic evolution of this crustal sector. In exploration geology, vitrinite reflectance provides data on hydrocarbon maturation by constraining organic matter maturity. In sedimentary basin modelling, it is adopted to define the palaeothermal regime. Vitrinite reflectance (Ro) also provides information on the burial history of sedimentary basins and may be employed to estimate tectonic uplift and erosion rates. Thermal Alteration Index (TAI) and fluorescence colour values can be correlated with Ro and may be used to estimate the degree of maturation when vitrinite is absent. Samples derived from the Sabini and Tiburtini Mts, in slope facies between the Latium–Abruzzi carbonate Platform and the Umbria–Marche pelagic Basin; from the Simbruini and Ernici Mts, in carbonate Platform facies, and from upper Miocene turbiditic deposits outcropping between the Olevano–Antrodoco Une, towards the West, and the Marsica slope facies, towards the East. Both the pre-terrigenous Meso-Cenozoic sequences show a low grade of organic maturity: the Sabini and Tiburtini Mts show Ro values that are less than 0.4%, and the Simbruini–Ernici Range show Ro values that range between 0.5% and 0.65%. Field analysis indicates that the cause of these low maturity levels is that thick sequences of turbidites were never deposited during the Neogene evolution of the Apennine thrust belt. Moreover, Upper Miocene turbiditic deposits also show low maturity levels, with Ro values that are less than 0.5%, indicating that these deposits were never overthrusted by huge volumes of rocks, during the chain building. The slight increase in the maturity level recorded in the Marsica area may be related to local heating along shear zones in areas of strike-slip tectonics.  相似文献   

13.
修正的镜质体反射率剥蚀厚度恢复方法   总被引:32,自引:0,他引:32  
针对目前用的地层剥蚀厚度恢复镜质体反射率差值法所存在问题,在考察地层沉降、抬升、再沉降埋藏史过程的基础上,根据有机质演化累积性和不可逆性原则,利用经典的有机质成熟度时温关系模型(TTI),建立了修正的镜质体反射率剥蚀厚度恢复方法。该方法不仅考虑了剥蚀界面上下镜质体反射率的相对值,还考虑了各自绝对量,与以往仅考虑镜质体反射率差值相比,有较大改进。  相似文献   

14.
Based on studies of the reflectance of Ordovician and Silurian zooclasts from 11 sections around the Huangling Anticline, Hubei, China, combined with determination of the conodont colour alteration indices (CAI) and of infrared spectroscopy of dispersed organic matter from the same or adjacent horizons, it is further proved that reflectances of graptolites, chitinozoans and scolecldonts, like vitrinite and natural bitumen, increase with increasing maturation, but follow different reflectance paths. They may be used, therefore, as thermal maturation indicators. Graptolites display optically strong anisotropy. The maximum reflectance measured from graptolite on polished section cut parallel to the bedding plane is the most suitable for determination of maturation of their host rocks. In polished section chitinozoan and scolecodont show reflectance, but no bireflectance owing to their isotropy. The random reflectance of chitinozoans is higher than that of scolecodonts in the case of the same maturity. By analysing the distribution trends of graptolite, chitionzoan and scolecodont reflectances, the Ordovician and Silurian strata can be subdivided into three areas of maturation in the present region. The potential of oil or gas generation is discussed for each area. The result is basically coincident with the distribution pattern of regional organic maturation presented by CAI and infrared spectroscopic determination of organic matter.  相似文献   

15.
不同变质程度煤的激光拉曼光谱特征   总被引:7,自引:1,他引:7  
对不同矿区,不同变质程度煤的9个镜煤样品进行了激光拉曼光谱测定,并对其特征光谱进行了参数化。在1000-2000cm^-1的波数范围内有两个明显的拉曼频率振动峰G峰和D峰。当镜质体反射率R0<2.28%时,D峰位置随R0的增大向低波数位置偏移。G峰与D峰峰位差和峰高比随R0的增大而增加。当R0约为2.1%时,拉曼光谱特征趋势发生逆转性变化。在2500-3250cm^-1之间有一个明显的拉曼谱带,并随煤变质程度的增加呈现如下规律,其谱带的变化与有机质的成熟度演化具有一珲的同步性,特别是在有机质进入成熟门限后,由于油相和气相成分的大量生成,出现明显的振动峰,而进入无烟煤(R0>4.4%)后,其振动峰变弱,因此,煤的激光拉曼光谱特征可作为油气盆地判断有机质成熟度的一个指标。  相似文献   

16.
The development of a qualifying system for reflectance analysis has been the scope of a working group within the International Committee for Coal and Organic Petrology (ICCP) since 1999, when J. Koch presented a system to qualify vitrinite particles according to their size, proximity to bright components and homogeneity of the surface. After some years of work aimed at improving the classification system using photomicrographs, it was decided to run a round robin exercise on microscopy samples. The classification system tested consists of three qualifiers ranging from excellent to low quality vitrinites with an additional option for unsuitable vitrinites. This paper reports on the results obtained by 22 analysts who were asked to measure random reflectance readings on vitrinite particles assigning to each reading a qualifier. Four samples containing different organic matter types and a variety of vitrinite occurrences have been analysed. Results indicated that the reflectance of particles classified as excellent, good or poor compared to the total average reflectance did not show trends to be systematically lower or higher for the four samples analysed. The differences in reflectance between the qualifiers for any given sample were lower than the scatter of vitrinite reflectance among participants. Overall, satisfactory results were obtained in determining the reflectance of vitrinite in the four samples analysed. This was so for samples having abundant and easy to identify vitrinites (higher plant-derived organic matter) as well as for samples with scarce and difficult to identify particles (samples with dominant marine-derived organic matter). The highest discrepancies were found for the organic-rich oil shales where the selection of the vitrinite population to measure proved to be particularly difficult. Special instructions should be provided for the analysis of this sort of samples. The certainty of identification of the vitrinite associated with the vitrinite reflectance values reported has been assessed through a reliability index which takes into account the number of readings and the coefficient of variation. The same statistical approach as that followed in the ICCP vitrinite reflectance accreditation program for single seam coals has been used for data evaluation. The results indicated low to medium dispersion for 17 out of 22 participants. This, combined with data from other sets of comparative analyses over a long period, is considered an encouraging result for the establishment of an accreditation program on vitrinite reflectance measurements in dispersed organic matter.  相似文献   

17.
姜峰  杜建国 《沉积学报》1998,16(3):153-155
对不成熟泥炭样品进行了高压(0.1~2GPa)、高温(200℃~400℃)模拟实验,并对实验后样品的成熟度指标--镜质体反射率(Ro)进行了测定。结果显示,同一压力条件下,温度与镜质体反射率呈正相关;相同温度条件下,样品Ro值与压力呈负相关,说明压力同温度一样,是影响有机质成熟作用的一个重要因素,其存在会抑制有机质向高成熟演化。压力的这种作用有其内在的化学动力学机理。实验结果及实际地质现象都说明,压力作用在有机质演化过程中不可忽视。用模拟实验手段探讨压力的作用和影响,具有重要的理论及实际意义。  相似文献   

18.
沉积盆地超压系统内油气的生成与保存   总被引:1,自引:0,他引:1  
肖七林  孙永革 《地球化学》2007,36(4):375-382
沉积盆地内的超压系统是一个相对独立的封闭-半封闭体系,与油气生成、保存关系密切.超压系统内矿物介质、有机质、水相互作用过程以及有效应力对有机质演化的作用机理研究揭示了超压对有机质演化具有显著的阶段性和差异性,具体表现在:(1)压力的影响程度是有机质演化程度的函数;(2)超压/压力效应对有机质演化发生显著影响需要达到某一最小值,即门限值;(3)在有机质演化不同阶段发育的超压对生烃的影响不同;(4)同一超压系统内,不同类型有机质对超压的响应具有差异性.迄今,已经建立了超压/压力对有机质演化影响程度的定量化模型,包括化学动力学模型和热力学模型两类.化学动力学模型仍有许多需要改进的地方,如压力影响的阀值、指前因子和活化能随反应时间的变化规律等,相对而言,热力学模型似乎更简单、易用,但其可靠性和普适性还有待时间的检验.由于异常高压对超压系统储层内原油的热裂解反应具有抑制效应,有利于深部高温高压储层内液态烃的保存,因此,含油气盆地深部高温高压地层已成为一个较为有利的石油勘探领域.  相似文献   

19.
在对比分析不同侵入体热传导模型的基础上,进一步结合Easy Ro%模型对前人报道的受岩浆侵入体影响的实测Ro数据进行了数值模拟,结果表明改进的Fjeldskaar模型具有较好的应用前景。同时侵入体不同初始温度及不同厚度对围岩热演化程度影响的数值模拟结果表明,岩浆侵入体的热作用范围有限,不同地质条件下,影响的范围不同。其中:侵入体初始温度越高,影响范围越大;侵入体厚度越大,影响范围(X/D值)也越大,但是一般X/D<2(X/D代表侵入体与接触面的距离和侵入体厚度的比值)。侵入体热传导模型的初步应用表明,岩浆作用带来的热源对烃源岩生烃进程产生了重要影响,可以加速烃源岩的成熟,使得生烃期提前。  相似文献   

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