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1.
生物降解作用对原油中烷基菲分布的影响 总被引：1，自引：0，他引：1
辽河盆地冷东油田原油来源单一,成熟度相近,生物降解是导致原油中烷基菲含量和组成发生变化的主要原因。通过对不同降解程度油砂样品中烷基菲含量和分布的详细地球化学分析,发现中等程度生物降解（3到5级）使烷基菲含量大大降低,而异构体相对含量的变化主要发生在中等程度生物降解之后（4级以上）,原油遭受4级以下生物降解影响时,烷基菲参数仍能有效指示成熟度。烷基菲生物降解的难易程度明显受烷基化程度的控制,C3-菲比低烷基取代化合物的抗生物降解能力强,但甲基菲比菲更容易降解,推测这与甲基菲的脱甲基作用有关。生物降解对烷基菲各异构体的消耗有强烈的选择性,在9位或 10位上取代的烷基菲比其他位置取代的烷基菲抗生物降解能力强,根据烷基菲系列中化合物相对含量随生物降解程度的变化,确定了甲基菲、C2-菲和C3-菲各异构体的生物降解顺序,研究成果为芳烃成熟度参数的合理选用和生物降解定量评价提供了依据。 相似文献
2.
生物降解原油中吡咯氮化合物组成的变化 总被引：1，自引：0，他引：1
渤海海域地区近50个原油样品中性氮组分的GC／MS定量分析资料表明,油藏中的生物降解作用对原油的吡咯氮化合物含量和分布有明显影响。经与同源未降解原油比较,各种烷基咔唑和苯并咔唑在3。4级中轻度降解油中就出现明显降解迹象,随生物降解程度增高其含量逐渐减少,在6—8级严重降解油中它们的总含量降低到原有的五分之一左右。在3—4级中轻度降解油中,裸露型甲基咔唑异构体更容易被微生物侵袭而代谢,抗生物降解能力按1-甲基咔唑〉4-甲基咔唑〉2-、3-甲基咔唑顺序递减;当降解程度更高时,这些化合物降解速率相当,1-／4-MCA等比值相对稳定。低-中等降解阶段,不同类型二甲基咔唑异构体的抗生物降解能力也存在明显差异性,呈屏蔽型〉半屏蔽型〉裸露型降低;在生物降解水平进一步增高时,这些异构体之间的相对含量变化不大。生物降解作用对苯并咔唑系列化合物分布的影响具有不确定性,且随降解程度的增加变得更为显著,降解油中【a】／[c】苯并咔唑比值或增高或降低。生物降解原油中吡咯氮化合物的组成变化,使降解油的二次运移示踪面临新的问题。 相似文献
3.
生物降解作用对烷基萘异构体分布的影响及其控制因素 总被引：1，自引：0，他引：1
在受到溢油污染的海滩上采集不同时间序列的石油样品,对芳烃组分烷基萘中的三甲基萘和四甲基萘各异构体的生物降解过程响应进行了详细分析。研究揭示,三甲基萘比四甲基萘更易被生物降解,其中1,2,7-三甲基萘、2,3,6-三甲基萘、2,3,6,7-四甲基萘、1,2,3,7-四甲基萘和1,3,5,7-四甲基萘等异构体具有相对较高的生物降解效率,与最近 Ostojié等利用理论模型计算所给出的降解序列十分一致,进一步证实了烷基萘在表生环境中的降解主要受控于异构体萘环上取代基的数量和位置。研究结果对于表生环境中萘系物类多环芳烃污染的生物修复评价具有重要指导意义。 相似文献
4.
系统剖析流花11-1礁灰岩油藏储层烃类的生物降解特征, 揭示油藏底水与隔夹层对原油生物降解程度具有显著控制效应, 这使得油藏原油生物降解程度及其分布预测更加复杂化.研究发现, 流花11-1油藏具有统一的油水界面, 油源类型单一, 原油成熟度较高且分布较窄, 可能为短期快速充注所形成的油藏.原油普遍遭受生物降解, 降解程度均小于6级.垂向上, 隔夹层虽可引起局部储层烃类降解程度的倒转, 但单井油柱生物降解等级仍以储层与油水界面的距离为主要控制因素, 表现为降解程度由顶部向底部呈明显梯度变化, 油藏底水控制效应明显.横向上, 油藏降解程度的差异主要由隔夹层控制下储层内原油与活跃底水的接触程度不同导致.在隔夹层密集发育区流体运动受阻, 进而使微生物营养物质供应不足, 代谢物质交换不畅, 原油降解程度相对较低.在上述研究的基础上, 建立了油藏底水与储层非均质性对原油生物降解程度的控制效应模型, 并探讨了该方法在稠油油藏开发中的应用. 相似文献
5.
对南羌塘坳陷古油藏开展了有机地球化学分析, 从生物标志化合物特征和地质条件探讨古油藏生物降解特征及成藏期次。研究表明, 古油藏储层样品抽提物的正构烷烃分布完整, 但色谱基线发生不同程度抬升, 形成“鼓包”现象, 指示古油藏遭受了一定程度的生物降解作用; 古油藏族组分碳同位素发生“倒转”和普遍检出的25-降藿烷也证实了古油藏经历了中等-严重的生物降解。然而, 古油藏储层样品饱和烃色谱图显示出正构烷烃较为完整, 指示古油藏储层可能经历两期原油充注, 第一次原油遭受了生物降解, 第二期原油保留相对完整的正构烷烃。古油藏储层经历了两次原油充注, 与南羌塘坳陷富有机质页岩经历了两次生排烃的过程是一致。 相似文献
6.
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
7.
原油生物降解模拟实验及其定量化评价 总被引：1，自引：0，他引：1
利用筛选到的优势烃降解复合菌(I菌)对大庆油田3口不同油井的油(西5-P10、三元后和G1131-262)进行不同时间的降解实验和全油GC-MS定量分析,探讨饱和烃、芳烃化合物分布情况变化。实验研究表明I菌为高效烃降解菌;相同微生物对此3种不同原油的降解能力存在明显的差异,所以烃污染现场生物修复试验需要根据不同原油性质选择不同的高效降解菌;对于饱和烃和芳烃生物降解的顺序既有对过去结论的验证又提出新的看法。藿烷的降解在重排甾烷之后,萘比菲先开始降解,三甲基萘比三甲基菲更早开始遭受生物降解,三甲基和四甲基萘在深度生物降解后会达到一个平衡,之后的降解速度减慢。当生物降解到一定阶段,抗生物降解能力强的多环芳烃富集会加重对环境的毒害,因此,多环芳烃降解菌或萘、菲降解菌等特效菌是未来烃污染环境修复工作的重点。 相似文献
8.
油藏原油微生物降解的氮同位素分馏效应 总被引：1，自引：0，他引：1
选取辽河油田冷东地区来自Es3烃源岩不同性质原油,测定氮同位素比值,试图分析生物降解过程中原油氮同位素的分馏作用,探讨含氮化合物组成的变化机理。正常原油与相应干酪根的氮同位素比值接近,δ15N分布在4.0‰左右。遭受生物降解的原油,氮同位素比值明显增加,δ15N接近或超过10.0‰。比较遭受不同程度微生物降解自然系列的原油,氮同位素比值的变化与降解程度相联系。微生物降解过程中发生氮同位素分馏作用这一事实暗示降解原油中含氮有机化合物在降解过程中参与了代谢。 相似文献
9.
石油烃中烷基萘的形成机理及其地球化学意义 总被引：2，自引：1，他引：1
烷基蓁是原油中的重要组成部分,在指示成岩演化环境和成熟度变化方面非常有效.原油中含α,β位取代基的烷基萘异构体含量变化趋势相反,此即为烷基萘成熟度参数提出的依据.着重综述了石油烃中甲基萘两种主要生成途径--分子异构化反应和甲基化、去甲基化反应及其反应机理,以及烷基萘参数的应用概况,阐述了生物降解作用、水洗作用、内源混合作用和有机质来源及其他因素对烷基萘参数的影响,探讨了烷基萘参数应用过程中存在的问题与不足,并展望了今后的发展趋势. 相似文献
10.
通过对准噶尔盆地中部Ш区块原油或油砂抽提物的饱和烃气相色谱-质谱分析,研究了原油或油砂抽提物中25-降藿烷的分布规律.结果表明,不同井区或同一口井不同深度(层位)的原油25-降藿烷的相对含量存在比较明显的差别,表明其所遭受的生物降解程度有所差异,沿构造带从南到北,同一油层中原油的生物降解程度增强,比如位于构造北部(构造部位相对较高)的永1井、永3井侏罗系原油25-降藿烷丰度较高,表明生物降解比较明显,而位于南部(构造低部位)的永6井白垩系和侏罗系油层中的原油均无明显的生物降解现象;同一口井随深度增大生物降解作用将弱,如永2井浅部白垩系油层的原油降解较严重,而深部西山窑组的原油降解作用则不明显.根据原油生物降解的特征,结合车-莫古隆起调整对研究区油气成藏的影响,讨论了原油生物降解差异分布的成因机制. 相似文献
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12.
生物降解原油地球化学研究新进展 总被引：18，自引：0，他引：18
生物降解作用是原油的一种重要的蚀变作用,对原油的物性和经济价值有着负面的影响。全球石油大多遭受过生物降解。生物降解作用对常见生物标志物的影响得以较好的描述,综述了近年来高分子量正构烷烃、三环萜烷、25 降藿烷生物降解的新进展。目前对生物降解作用的细节、发生机理尚不十分清楚,讨论了原油喜氧和厌氧降解机制,认为厌氧作用可能起主导作用,降解速率很慢。温度是控制生物降解作用的重要因素,储层温度大于80℃不会发生生物降解作用。生物降解原油多为混源油,介绍了研究生物降解原油的多期成藏方法。沥青质不易生物降解,其热解产物及钌离子催化氧化产物在生物降解原油对比、油源对比中具有重要的作用;最后指出了今后的发展方向。 相似文献
13.
东营凹陷生物降解稠油甾烷分子的选择蚀变 总被引：1，自引：0，他引：1
为分析生物降解原油中甾烷生物标志物分子发生选择性蚀变的先后顺序及生物降解作用对甾烷分子成熟度参数的影响,在渤海湾盆地东营凹陷广饶潜山油藏选择了发生不同程度生物降解作用的原油,利用色谱质谱(GC-MS)仪对其中甾烷进行了定量测试分析和对比。结果发现在生物降解过程中,不同级别的生物降解作用对甾烷具有不同程度的影响:6级以下的生物降解作用对甾烷的降解能力有限,甾烷及其相关化合物比值没有可以识别的改变;6级以上的严重生物降解作用会对甾烷生物标志物的相关参数产生显著的影响。在严重生物降解原油中(级别≥6):甾烷系列被降解和蚀耗的先后顺序为,ααα20R>αββ20R>αββ20S≥ααα20S,C27>C29>C28,规则甾烷优先于重排甾烷发生降解,C27,C28,C29甾烷优先于C20,C21甾烷发生降解;甾烷生物标志物分子参数C2920S/(20S+20R),C29ββ/(ββ+αα)会发生显著升高,不能真实反映成熟度大小。研究结果为正确评价生物降解原油的成熟度及甾烷生物标志物分子的选择性蚀变提供了新的科学依据。 相似文献
14.
The effect of biodegradation on polycyclic aromatic hydrocarbons in reservoired oils from the Liaohe basin, NE China 总被引：3，自引：0，他引：3
Haiping Huang Bernard F.J. Bowler Thomas B.P. Oldenburg Steve R. Larter 《Organic Geochemistry》2004,35(11-12):1619
The occurrence and distribution of polycyclic aromatic hydrocarbons (PAHs) has been studied in oil columns from the Liaohe basin, NE China, characterized by varied degrees of biodegradation. The Es3 oil column has undergone light to moderate biodegradation – ranging from levels 2 to 5 on the [Peters, K.E., Moldowan, J.M., 1993. The Biomarker Guide: Interpreting Molecular Fossils in Petroleum and Ancient Sediments. Prentice Hall, Englewood Cliffs, NJ, p. 363] scale (abbreviated as ‘PM level’) – while the shallower Es1 column has undergone more severe biodegradation, ranging from PM level 5 to 8. Both columns show excellent vertical biodegradation gradients, with degree of biodegradation increasing with increasing depth toward the oil–water contact (OWC). The compositional gradients in the oil columns imply mass transport control on degradation rates, with degradation occurring primarily at the OWC. The diffusion of hydrocarbons to the OWC zone will be the ultimate control on the maximum degradation rate. The chemical composition and physical properties of the reservoired oils, and the ‘degradation sequence’ of chemical components are determined by mixing of fresh oil with biodegraded oil.The PAH concentrations and molecular distributions in the reservoired oils from these biodegraded columns show systematic changes with increasing degree of biodegradation. The C3+-alkylbenzenes are the first compounds to be depleted in the aromatic fraction. Concentrations of the C0–5-alkylnaphthalenes and the C0–3-alkylphenanthrenes decrease markedly during PM levels 3–5, while significant isomer variations occur at more advanced stages of biodegradation (>PM level 4).The degree of alkylation is a critical factor controlling the rate of biodegradation; in most cases the rate decreases with increasing number of alkyl substituents. However, we have observed that C3-naphthalenes concentrations decrease faster than those of C2-naphthalenes, and methylphenanthrenes concentrations decrease faster than that of phenanthrene. Demethylation of a substituted compound is inferred as a possible reaction in the biodegradation process.Differential degradation of specific alkylated isomers was observed in our sample set. The relative susceptibility of the individual dimethylnaphthalene, trimethylnaphthalene, tetramethylnaphthalene, pentamethylnaphthalene, methylphenanthrene, dimethylphenanthrene and trimethylphenanthrene isomers to biodegradation was determined. The C20 and C21 short side-chained triaromatic steroid hydrocarbons are degraded more readily than their C26–28 long side-chained counterparts. The C21–22-monoaromatic steroid hydrocarbons (MAS) appear to be more resistant to biodegradation than the C27–29-MAS.Interestingly, the most thermally stable PAH isomers are more susceptible to biodegradation than less thermally stable isomers, suggesting that selectivity during biodegradation is not solely controlled by thermodynamic stability and that susceptibility to biodegradation may be related to stereochemical structure. Many commonly used aromatic hydrocarbon maturity parameters are no longer valid after biodegradation to PM level 4 although some ratios change later than others. The distribution of PAHs coupled with knowledge of their biodegradation characteristics constitutes a useful probe for the study of biodegradation processes and can provide insight into the mechanisms of biodegradation of reservoired oil. 相似文献
15.
Elham ASADI MEHMANDOSTI Mahnaz AMIRHOSEYNI Seyed Ali MOALLEMI Azizollah HABIBI 《《地质学报》英文版》2022,96(2):546-558
Crude oil and source rock samples from one of the main oilfields of the Abadan Plain, Zagros, Iran were analyzed geochemically. Rock-Eval pyrolysis was conducted on Kazhdumi (Upper Cretaceous) and Gadvan (Lower Cretaceous) formations, which are the probable source rocks for the oil in the region. The results indicated that the Kazhdumi Formation can be classified as a fair-to-excellent source rock, while the Gadvan Formation can be identified as having poor-to-good source rock in the basin. Based on the cross-plots of HI versus OI and S2 versus TOC, types II and III kerogen were identified from studied source samples in the area. Determination of the main fraction percentages of the Sarvak and Fahliyan crude oils represented that the oils from the Sarvak reservoir are paraffinic-naphthenic and aromatic-intermediate, whilst that from the Fahliyan reservoir is paraffinic and paraffinic-naphthenic. Biomarker ratios of the saturated fractions of oil from both reservoirs indicate that the source rocks formed in reducing marine environments with carbonate-shale lithology. Furthermore, biomarker data helped to distinguish the degree of biodegradation in the studied oils. According to geochemical analysis, oil samples from the Fahliyan reservoir were generated at a higher thermal maturity than the Sarvak reservoir samples. 相似文献
16.
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
17.
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
18.
We have investigated the distributions of alkylcarbazoles in a series of crude oils with different biodegradation extents,
in combination with biomarker parameters, stable carbon isotopic ratios and viscosities. The analyses showed that slight biodegradation
has little effect on alkylcarbazoles. The concentrations of C0-, C1-, and C2-carbazoles seem to display a slight decrease with biodegradation through the moderately biodegraded stage, and an abrupt
decrease to the heavily biodegraded stage. The relative concentrations of C0-, C1-, and C2-carbazoles do not show any apparent change in the non-heavily biodegraded stages, but through non-heavily biodegraded to
heavily biodegraded stages, the percentages of C0- and C1-carbazoles decrease, and those of C2-carbazoles increase significantly, which may indicate that C2-carbazoles are more resistant to biodegradation than lower homologous species. As to C2-carbazole isomers, the relative concentrations of the pyrrolic N-H-shielded, pyrrolic N−H partially shielded and pyrrolic
N-H-exposed isomers do not show any obvious variation in the non-heavily biodegraded oil, but there is an abrupt change through
the mid-biodegraded stage to the heavily biodegraded stage.
This project was financially supported by the Youth Knowledge-Innovation Foundation of CNPC (No. 00Z1304). 相似文献