共查询到20条相似文献，搜索用时 437 毫秒
1.
John K. Volkman Robert Alexander Robert Ian Kagi Garry Wayne Woodhouse 《Geochimica et cosmochimica acta》1983,47(4):785-794
Analyses of some Australian crude oils show that many contain varying concentrations of A/ B-ring demethylated hopanes. These range from C26 to C34 and have been identified from their retention times and mass spectral data as 17α(H)-25-norhopanes. Comparison of hopane and demethylated hopane concentrations and distributions in source-related, biodegraded oils suggests that demethylated hopanes are biotransformation products of the hopanes. Further, it appears that the process occurs at a late stage of biodegradation, after partial degradation of steranes has occurred. Demethylated hopanes are proposed as biomarkers for this stage of severe biodegradation. The presence of these compounds in apparently undegraded crude oils is thought to be due to the presence of biodegraded crude oil residues which have been dissolved by the undegraded crude oil during accumulation in the reservoir sands. The timing of hopane demethylation, relative to the degradation of other compounds, has been assessed and the progressive changes in crude oil composition with increasing extent of biodegradation have been identified. The use of demethylated hopanes as maturity parameters for severely biodegraded crude oils, and the applicability of established biomarker maturity parameters to such oils, are also discussed. 相似文献
2.
3.
John K. Volkman Robert Alexander Robert Ian Kagi Rohinton A. Noble Carry Wayne Woodhouse 《Geochimica et cosmochimica acta》1983,47(12):2091-2105
A suite of crude oils and petroleum source rock extracts from the Barrow Sub-basin of Western Australia have been analysed for biological marker compounds by capillary GC-MS, and for volatile hydrocarbons by whole oil capillary GC. These analyses were used to calculate values for twenty-three biomarker parameters in order to assess aspects of source type, maturity, migration and biodegradation of the hydrocarbons.The crude oils had a source in the Upper Jurassic Dingo Claystone formation. These hydrocarbons accumulated in the reservoir sands and in some cases were biodegraded. Several accumulation and biodegradation episodes have been recognised while the basin continued to subside, which resulted in a suite of oils showing marked differences in composition. 相似文献
4.
塔里木盆地原油的成因研究 总被引：9，自引：0，他引：9
对塔里木盆地原油和生油岩饱和烃进行ＧＣ－Ｃ－ＭＳ和ＧＣ－ＭＳ分析，利用单个正构烷烃碳同位素组成和三环萜烷分布特征进行油源对比，研究了塔里木盆地原油的油源问题；根据寒武—奥陶系富含菌藻有机质生油岩饱和烃色谱分析结果，对塔里木盆地海相原油含蜡较高的成因进行了探讨 相似文献
5.
Zhihuan Zhang Liming Qin Wei Li Chunjiang Wang Nansheng Qiu Xianlong Meng Zhenying Zhang Dongshan Yuan 《中国地球化学学报》2010,29(2):121-129
Geochemical composition characteristics of light oils from the Tertiary in the west of the Chepaizi uplift in the Junggar basin, northwest China, are distinct from those of biodegraded oils derived from the Permian in the study area and crude oils from some adjacent oil fields such as the Chepaizi and Xiaoguai oilfields. Oil source correlation shows that light oils in the study area have similar n-alkane and isoprenoid distribution patterns and carbon isotope compositions with the coal-derived oils from the Jurassic, and display obvious discrepancy on biomarker composition characteristics with the Cretaceous source rock extracts, inferring that they are probably the mixed oils from the Jurassic coal measures and Cretaceous source rocks. In this study, combined with the geochemical data of coal-derived oils from the Jurassic and Cretaceous source rocks or crude oils from the Cretaceous, the source and commingling features of the Tertiary crude oils of Well Pai 2 and Well Pai 8 were investigated. The proportion of the two sources in the mixed crude oils was estimated, and the hydrocarbon accumulation pattern of reservoirs in the study area was established. 相似文献
6.
Manoj Kumar Sarmah Srinivasan V. Raju 《Journal of the Geological Society of India》2016,87(3):327-336
The crude oils from Oligocene and Miocene formation of upper Assam basin have moderate API gravity and significant wax content. Crude oils from HJN and MKM fields of upper Assam basin are being produced from Oligocene and Miocene sands. These oils are somewhat biodegraded in nature as evidenced from their API gravity, density, bulk composition, GC fingerprints and relative concentrations of compounds in the gasoline range. It is observed from whole oil gas chromatographic data that the lighter hydrocarbons are more effected as a result of biodegradation and water washing than the heavier components. In the gasoline range compounds highest degradation of n-alkanes are observed followed by iso- and cyclo- alkanes. The extent of the effect of biodegradation of the gasoline range compounds in crude oil samples cannot be illustrated by the concentrations of the compounds. The concentrations only describe qualitative differences in molecular composition. This difficulty can be overcome by using parameters called degradative loss (%). This parameter shows exactly how much loss or gain has taken place in the gasoline range compounds. Within the gasoline range compounds, n-alkanes, Benzene baring HJN 15 and MKM 14 and Toluene experienced degradative loss indicating effects of both biodegradation and water washing in these oils. Cyclo-alkanes are least effected by biodegradation followed by iso-alkanes in all the oils. The extent of biodegradation and water washing is different for each oils from HJN and MKM fields as indicated by the degradative loss (%) of the compounds in the gasoline range. 相似文献
7.
R.P. Philp 《Geochimica et cosmochimica acta》1983,47(2):267-275
The aliphatic hydrocarbon fractions of sixty oils from the San Jorges Basin, Argentina have been analysed by computerized-gas chromatography-mass spectrometry. The initial aim of this study was the correlation of the oils using sterane and triterpane biomarkers. The oils could be divided into four groups which were distinguished by the relative proportions of regular to demethylated hopanes. Although it has been previously suggested that the demethylated hopanes found in oils could have resulted from biotransformation of the oils in the reservoir, in this basin the possibility that these compounds originated directly from the source beds cannot be entirely eliminated since the oils do not appear to be extensively biodegraded on the basis of their aliphatic hydrocarbon distributions. An alternative theory for the hydrocarbon distributions observed in these oils, is initially biodegradation of the oils in the reservoir followed by addition of non-degraded oil to produce a mixture of degraded and non-degraded oil. 相似文献
8.
《Applied Geochemistry》1997,12(3):229-241
The fluorescence spectra of crude oils, synthesized as hydrocarbon fluid inclusions (hcfi) in NaCI crystals, have been recorded and correlated with crude oil chemical analysis. The crude oils represent a wide range in total hydrocarbons, saturate and aromatic fractions, and resin-asphaltene concentration. The fluorescence properties (Lambda max and Q) of the hydrocarbon fluid inclusions display a systematic red shift to longer wavelengths from 440 nm to 595 nm with increasing aromatic content and increasing concentration of NSO-bearing compounds. A positive correlation also exists between Lmax-Q and the thermal maturity parameters nC17/pristane and nC18/phytane. First order linear regression equations provide a method for constraining the chemical composition of natural hydrocarbon fluid inclusions. Lmax and Q correlate positively with oil density (°API), providing for an indirect method of estimating the API of a natural hydrocarbon fluid inclusion assemblage. Fluorescence spectra of non-biodegraded crude oils from the Upper Devonian Birdbear Formation, Saskatchewan, Canada, have been correlated with regionally widespread hcfi within carbonate carrier beds and reservoir rocks of the same formation. The two most dominant types of hcfi spectra match well with the fluorescence spectra from crude oils within the Birdbear Formation. A third, less common population of very-blue fluorescing hcfi (Lmax=415440 nm, Q ≤ 0.10) also occur within fractures, intercrystalfne cements or in fossil overgrowths. The Lmax-Q-API-chemical correlations establised for the synthetic hcfi suggests that the °API of these inclusions is probably > 45° and the saturate/aromatic ratio ranges from 3.2 to 5.1. Spectra from hcfi within quartz overgrowths and cements, fractures and carbonate cements from sandstone reservoirs in the Jeanne d'Arc Basin offshore Newfoundland, compared with fluorescence spectra of crude oils suggests that some of the reservoirs may have been filled by a relatively low maturity oil and then a higher maturity oil. This is reflected in the intermediate spectra of the crude oils relative to the spectra of two separate hcfi events. Other reservoirs appear to have been charged with a relatively high gravity oil which was later biodegraded. This is marked by a blue region spectra for the hcfi compared with a red-shifted spectra for the crude oil (°API = 19). The API of the original unaltered oil which charged the reservoir is estimated to be between 32 and 38° using the Lmax-Q-API relationship established for the synthetic hcfi. 相似文献
9.
Hydrous pyrolysis of asphaltenes has been tested as a method to reconstruct the chemical composition of biodegraded oils and oil seeps. The asphaltenes of three oils (a nondegraded oil, a biodegraded oil, and a biodegraded oil seep) from the Monterey Formation were studied. Results show that the aliphatic fraction generated by hydrous pyrolysis is very similar in chemical composition to the non-degraded oil. This makes the method very useful in correlation studies of biodegraded and nondegraded oils. It also allows to roughly estimate the maturity of the source of the biodegraded oil or oil seep. 相似文献
10.
11.
In this study,12 crude oil samples were collected and analyzed from the Ordovician reservoir in the Halahatang Depression,Tarim Basin,China.Although the density of oil samples varies considerably,based on saturated hydrocarbon gas chromatographic(GC),saturated and aromatic hydrocarbon gas chromatographic-mass spectrometric(GC/MS) and stable carbon isotopic composition analyses,all the samples are interpreted to represent a single oil population with similar characteristics in a source bed or a source kitchen,organic facies and even in oil charge history.The co-existence of a full suite of n-alkanes and acyclic isoprenoids with UCM and 25-norhopanes in the crude oil samples indicates mixing of biodegraded oil with fresher non-biodegraded oil in the Ordovician reservoir.Moreover,according to the conversion diagram of double filling ratios for subsurface mixed crude oils,biodegraded/non-biodegraded oil ratios were determined as in the range from 58/42 to 4/96.Based on oil density and oil mix ratio,the oils can be divided into two groups:Group 1,with specific density>0.88(g/cm3) and oil mix ratio>1,occurring in the north of the Upper Ordovician Lianglitage and Sangtamu Formation pinchout lines,and Group 2,with specific density<0.88(g/cm3) and oil mix ratio<1,occurring in the south of the pinchout lines.Obviously,Group 2 oils with low densities and being dominated by non-biodegraded oils are better than Group 1 oils with respect to quality.It is suggested that more attention should be paid to the area in the south of the Upper Ordovician Lianglitage and Sangtamu Formation pinchout lines for further exploration. 相似文献
12.
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 C1–4 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. 相似文献
13.
借助于定量GC—MS分析技术,系统分析了一组取自辽河油田生物降解程度不同的原油芳烃馏分中三芴系列的组成特征。结果表明在生物降解过程中三芴系列化合物很容易遭受生物降解。母体三芴化合物在原油轻微降解阶段抗降解能力相似,其相对组成保持基本稳定,仍可指示沉积环境的性质;但进入中等及以上程度降解作用后,抗生物降解能力出现差异,相对组成发生变异,失去其环境意义。在甲基三芴系列中,甲基硫芴的抗降解能力强于甲基芴和甲基氧芴,降解速率不一致,组成特征不断变化,使甲基三芴系列相对组成不能指示沉积环境的性质。“三芴系列”被细菌消耗的速率不同,整个生物降解过程中其相对组成都在发生变化,因此对生物降解原油而言,无论其降解程度如何,“三芴系列”相对组成特征均不能有效的指示沉积环境的性质。 相似文献
14.
The distribution of the aromatic steroids and hopanoids in six crude oils was determined using comprehensive two dimensional gas chromatography time-of-flight mass spectrometry (GCxGC-TOFMS) in order to improve their identification and application in geochemical studies. Co-elution between monoaromatic and triaromatic steroids and benzohopanes and their methylated homologues, which are commonly observed in 1D conventional GC, were resolved, with GCxGC facilitating recognition of the compounds. One important feature was that, despite the oils showing mid-oil window maturity characteristics, the distribution of long chain aromatic steroids decreased in lacustrine samples vs. marine samples. This difference in the distribution of long chain and short chain aromatic steroids may reflect the different origins of these oils although this aspect needs further evaluation. 相似文献
15.
This work presents a study of the molecular composition of the saturated and aromatic hydrocarbon fractions of crude oils from the Orinoco Oil Belt (Junín area) in the Eastern Venezuelan Basin, with the purpose of classifying these samples following two distinct biodegradation assessment schemes: the PM scale [Peters, K.E., Moldowan, J.M., 1993. The Biomarker Guide: Interpreting Molecular Fossils in Petroleum and Ancient Sediments. Prentice Hall, Englewood Cliffs, New Jersey, p. 363] and the Manco scale [Larter, S., Huang, H., Adams, J., Bennett, B., Snowdon, L.R., 2012. A practical biodegradation scale for use in reservoir geochemical studies of biodegraded oils. Organic Geochemistry 45, 66–76]. Both scales agree on the presence of different levels of biodegradation for the analyzed oils, although they are based on different groups of compounds. The PM scale uses mainly compounds from the saturated hydrocarbon fractions (e.g., n-alkanes, acyclic isoprenoids, terpanes and steranes) as well as aromatic steroids. On the other hand, the Manco scale considers other compounds (e.g., alkyltoluenes, naphthalene, methylnaphthalene, phenanthrene, alkylphenanthrenes and methyldibenzothiophenes) not included in the PM biodegradation scale. Thus, the combined use of these two scales allows the determination of the level of biodegradation of both saturated and aromatic compound classes. Dibenzothiophene (DBT), which was not included for the Manco score determination, also shows variations in peak intensity when compared to C4-alkylnaphthalenes, presumably associated with the process of biological alteration. The differences in the biodegradation levels observed in the present study may be attributed to variations in parameters that control biodegradation rates laterally across the study area or the existence of varying communities of microorganisms, among other possible factors. 相似文献
16.
17.
《Applied Geochemistry》2002,17(1):1-10
The aliphatic hydrocarbon composition (acyclic isoprenoids, hopanoids and steroids) of oils from the most productive fields in the southern geological Province of Cuba have been studied. This province is defined by its position with respect to the Cretaceous overthrust belt generated during the formation of oceanic crust along the axis of the proto-Caribbean Basin. The relative abundances of 18α(H)-22,29,30-trisnorneohopane, gammacerane and diasteranes suggest that Pina oils are related to the carbonate oils from the Placetas Unit in the northern province (low Ts/(Ts+Tm) and C27,29 rr/(rr+sd) ratios). The Cristales and Jatibonico oils exhibit some differentiating features such as higher Ts/(Ts+Tm) and absence of gammacerane. The oils from this province do not exhibit significant differences in either hopane, C32 22S/(S+R) and C30 αβ/(αβ+βα), or sterane, C29 αα 20S/(S+R), maturity ratios. However, the relative content of 5α(H),14β(H),17β(H)-cholestanes (C29 ββ/(ββ+αα) ratio) indicates that Pina oils are more mature than Cristales and Jatibonico oils. Several of these oils (Cristales, Jatibonico and Pina 26) are heavily biodegraded, lacking n-alkanes, norpristane, pristane and phytane (the two former oils do not contain acyclic isoprenoid hydrocarbons). Other biodegradation products, the 25-norhopanes, are found in all the oils. Their occurrence is probably due to mixing of severely biodegraded oil residues with undegraded crude oils during accumulation in the reservoir. 相似文献
18.
苏丹Muglad盆地Fula坳陷油气地球化学特征与成藏意义 总被引：2，自引：0，他引：2
Fula坳陷位于Muglad盆地东北部,面积约5 000 km2,FN油田是该坳陷最大的亿吨级油田。油气储层主要为白垩系Abu Gabra、Bentiu和Aradeiba组。应用油藏地球化学的方法对FN油田的成藏期次进行了探讨。FN油田Abu Gabra、Bentiu和Aradeiba组原油特征相似,来源于同一套烃源岩,原油既表现出正构烷烃、藿烷、甾烷系列分布完整等正常油特征,又表现出色谱基线抬升、高峰度UCM、25 降藿烷出现等生物降解油特征,这些特征表明FN油田经历了至少两期成藏过程,早期充注的原油遭受生物降解后又接受后期成熟度较高的原油充注。根据构造演化、埋藏史和生排烃史可以研究生烃期次及油气成藏特征。Abu Gabra组烃源岩发生了两次生烃作用,第一次生烃作用发生在晚白垩世,Ro达到0.6%以上,进入生排烃作用阶段,晚白垩世末构造抬升作用使这次生烃产物遭受较为严重的生物降解;第二次生烃作用发生在古近纪,Abu Gabra组烃源岩进入生油高峰阶段,是本区最重要的一次生油作用和成藏过程,与该次成藏事件相关的构造圈闭是Fula坳陷油气勘探的重点。 相似文献
19.
Sulphur-containing compounds in sulphur-rich crude oils from hypersaline lake sediments and their geochemical implications 总被引：1，自引：0，他引：1
Guoying Sheng Jiamo Fu S. C. Brassell A. P. Gowar G. Eglinton Jaap S. Sinninghe Damste Jan W. de Leeuw P. A. Schenck 《中国地球化学学报》1987,6(2):115-126
Three sulphur-rich commercial crude oils have been studied, which contain sulphur as high as up to 4–12%. These samples were
collected from Tertiary hypersaline lake sediments of the Jianghan Basin, Hubei Province at different depths, but above the
oil generation threshold (2200m). FPD-GC and GC-MS data show that aromatic fractions of the crude oils are composed of different
homologues of sulphur-containing compounds, including long-chain normal alkyl-thiophenes and-thiolanes, long-chain isoprenoid-thiophenes
and -thiolanes, and benzothiophenes. It is worth noting that the distribution patterns of long-chain alkyl-thiophenes and
-thiolanes from two shallow-seated crude oils are quite similar to those of normal alkanes showing marked even-odd predominance.
It seems that the even-odd predominance of sulphur-containing compounds decreases with increasing burial depth of the crude
oils. The major component of aliphatic fraction is phytane, and similarly the major peaks of aromatic fractions also represent
C20 isoprenoid thiophenes.
Some preliminary conclusions have been drawn from the above discussion: (1) Abundant sulphur-containing compounds may be used
as an indicator of low mature or immature crude oils produced from hypersaline lake sediments; (2) Sulphur-containing compounds
are considered to be early diagenetic products of reactions between elemental sulphur or sulfides and alkanes or their precursors
(phytols, fatty acids, alcohols, etc.), or of bacterial activities, but not direct inputs of organisms. 相似文献
20.
Physical simulation experiment on oil displacement is an important approach to understand the mechanism and efficiency of displacement. Physical simulation experiments on water-flooding and chemical flooding in real cores with different lithologies and physical properties, reservoir Rock-Eval, TLC-FID, GC of saturated hydrocarbon fractions and GC-MS of saturated and aromatic hydrocarbon fractions were performed to investigate differences in the geochemistry of residual oils in the cores processed by water-flooding and chemical flooding. After fine sandstone was displaced with the two methods, the preferable replacement efficiency was displayed by the chemical constitutions of residual oils. As to glutenite, water-flooding is less effective, while chemical flooding has excellent performance according to changes in chemical compounds in oils. The results showed that the geochemical characteristics of the reservoir oils and lithology and physical properties of reservoir bed need to be considered in selecting replacement methods. In addition, the geochemical parameters for residual oils slightly changed during water-flooding and chemical flooding, which suggested the water-flooding and chemical flooding could not affect the application of these parameters in geochemistry. 相似文献