超压条件下的油藏地球化学特征

烃源岩成烃演化时，除了温度和时间的重要影响外，压力在油气生成演化过程中的作用也日益引起重视。压力对烃源岩中干酪根的热降解有阻滞作用，压力升高不仅使干酪根的化学键更稳定且不宜断裂，还使干酪根分子与烃源岩矿物结合更加牢固。通过歧北地区古近系深层超压油气藏研究，从油藏地球化学角度出发，较为细致的分析了超压条件下的油气生成、运移、聚集特征。     

塔里木盆地塔河油田石炭系、三叠系原油地球化学特征及成因研究

塔河油田是塔里木盆地迄今为止最大的海相碳酸盐岩油田,其成因备受关注.本文通过采样和气相色谱-质谱联用仪( GC-MS)分析,研究了塔河油田石炭系和三叠系原油地球化学特征及成因,研究结果表明:原油中Pr/Ph比值相对较低,Pr/nC17和Ph/nC18相关图反映其形成于还原环境;原油中含有相对丰富的伽马蜡烷和C30+藿烷...     

塔里木盆地西部古盐岩同位素地球化学与成钾预测研究

我国钾盐资源紧缺，寻找优质大型钾盐矿床一直是国家资源普查的重要目标这一。塔里木盆地在其地史发展过程中，曾与广海相通，多期海水的侵入和间断，以及适宜的构造、古地里环境具备成钾的基本地质条件，因此一直被列为我国寻找古钾矿的重点地区。为了更准备地判断其成盐的海陆相特征，即成盐物质的主要来源，以及岩盐沉积之前的古卤水蒸发浓缩阶段，预测更有前景的成钾远景区，论文选择了蒸发岩沉积序列中的石膏及石盐矿物，分别分析了其硫同位素及氯同位素分布特征。结果表明，非还原环境下沉积的石膏硫同位素可以准确判断盐岩沉积的海相、陆相和海陆交互沉积特征，氯同位素可以判断岩盐的沉积阶段。应用这两个同位素新指标分析，塔里木盆地西部喀什次级构造凹陷晚白垩世盐岩沉积接近海相沉积类型，而且岩盐沉积阶段较晚，是一最有利成钾远景区。     

塔里木盆地海相碳酸盐岩沥青"A"的地球化学特征

塔里木盆地采集的海相碳酸盐岩样品经粉碎后在索氏抽提器中用氯仿溶液抽提,正己烷沉淀沥青质后,可溶有机质进行柱色层族组成分离,获得饱和烃、芳烃、非烃,饱和烃和芳烃直接进行气相色谱-质谱分析,非烃经三氟化硼-甲醇混合液酯化后进行气相色谱-质谱分析。结果显示,样品有机质的演化程度高,母质类型以水生生物为主,台地相成烃古环境为富含单质硫的微生物发育的咸化深水还原环境。样品有机质经历过强烈的环化-芳构化过程和去甲基化过程有利于以甲烷为主的天然气的生成。样品的芳烃馏分中检测到C31-16-one、C33-16-one和C35-18-one长链中位酮化合物,推断这些长链中位酮可能是有机酸盐存在的特征生物标识化合物。     

塔里木盆地一类新海相原油的地球化学特征

对塔中52等井奥陶系储层产出的原油进行的分析结果表明,它们的三环萜烷系列较为特殊,主要表现为其相对丰度呈C19〉C20〉C21〉C23〉C24〉C25〉C26阶梯状的模式,C24四环萜烷异常丰富,且其丰度远高于C26三环萜烷,这一分布模式一般出现在淡水沼泽相和浅湖相沉积地层与原油中。在三萜烷分布特征上,其伽马蜡烷含量很低,甾烷系列和藿烷系列的分布与组成特征与该地区来源于中上奥陶统烃源岩的海相原油十分接近,同时它们的全油均具有轻的碳同位素组成,其δ13C值都小于-30‰,具有海相成因原油的特征。而塔中12井上奥陶统良里塔格组4-5段烃源岩中生物标志物的分析结果进一步证实了该类原油与那些富含宏观藻     

塔里木原油芳烃的地球化学特征

塔里木不同类型原油的芳烃分布和组成有较大差异。陆相原油的萘系列、二苯并噻吩系列（１．４１－３．０７％）较少；菲系列、联苯系列（平均值２０．４％）和二苯并呋喃系列较丰富；萘系列中有较高的１，２，５－三甲基萘和１，２，５，６－四甲基萘。海相原油中二苯并噻吩化合物含量高（７．７０％－３１．２４％）。这反映出两类原油成油母质的沉积环境和生源的差别。芳烃成熟度指标表明，这些原油相当的Ｒ０值在０．６％－１．１     

塔里木盆地陆相原油的地球化学特征

塔里木陆相原油来自中生界下，下侏罗一三叠烃源岩，从成因上主要可分有泊油和煤成汪两类，它们低硫，中一高蜡，低Ｖ／Ｎｉ。饱和烃呈姥鲛烷优势，Ｐｒ／Ｐｈ一般在１．５０～３．００之间，藿烷丰富甾较少，藿／甾比在６．２５～１２．２４之间，三环萜烷含量低，以低碳数（Ｃ１９～Ｃ２１）化合物占优势，其中湖泊由以Ｃ２１为主峰，煤成油以Ｃ１９为主峰，它们含丰富的重排二环倍半萜烷，重排藿烷，Ｃ２９Ｔｓ化合物和未知的Ｃ３     

广东雷州半岛玄武岩地下水水文地球化学特征及演化模拟

应用水化学分析软件和水-岩作用模拟软件对雷州半岛的水文地球化学进行了分析和路径模拟。沿东、西2个地下水径流方向从一级台地补给区至二级台地、三级台地排泄区的模拟计算结果表明,地下水可能经历了一系列复杂的水-岩作用,包括石膏、高岭石、钙蒙脱石、伊利石、绿泥石、斜辉石(或透辉石)、针铁矿、赤铁矿的溶解或沉淀及CO2气体的溶解或逸出等地球化学反应。针铁矿、赤铁矿和透辉石的溶解或沉淀量在沿东面地下水径流方向上远小于沿西面方向;针铁矿和赤铁矿只在少量水点发生溶解进入地下水,在大多数水点处于饱和状态而从地下水中析出;CO2气体在大多数取样点发生溶解进入地下水中,其溶解量较大,且随着CO2在水中浓度的变大,其饱和指数也增大,达到饱和后从水中逸出。可见水-岩作用模拟结果有助于揭示研究区地下水化学环境的演化机制。     

塔里木盆地北部油气地球化学特征及异常成因探讨

为了发挥油气化探“迅速掌握全局快速缩小靶区”的战略性作用,服务油气化探全国扫面计划,选择塔里木含油气盆地北部开展低密度(1点/25 km²)油气地球化学填图试点。油气化探填图指标土壤酸解烃、顶空气轻烃、荧光光谱、紫外吸收光谱和蚀变碳酸盐在大型油气田、油气富集区带上方均发育地球化学省异常,异常平面空间分布与地下油气富集区带具有良好的套合关系,对油气富集具有指示意义。区域性的荧光光谱等指标异常浓集中心沿轮台断裂等主干断裂带分布,与地下断裂位置良好的匹配性指示了油气大规模的运聚。甲烷碳同位素证实研究区油气地球化学省异常成因为热解成因,土壤样品三维荧光光谱发育共性峰,三维荧光光谱指纹特征反映了近地表土壤烃类异常与地下油气运移和油气藏类型相关。塔里木盆地北部地区油气地球化学填图试点结果表明,大型盆地可以采用甚低密度油气地球化学填图技术,圈出寻找大、中型油气田和油气富集区带的异常区,发挥油气化探“迅速掌握全局快速缩小靶区”的战略性作用。     

塔里木盆地原油轻烃地球化学特征

通过塔里木盆地５４０个原油要品中轻烃,尤其是Ｃ７烃类异构烷烃、环烷烃和正构烷烃的研究,认识到２－ＭＨ与３－ＭＨ化合物之间的相关性要高于２－ＭＨ与２－ＭＰ化合物之间的相关性,而ＭＣＰ与ＭＣＨ的化合物之间的相关性最差。原油Ｋ１值分布在０．７８－１．５４之间,其中８０％原油样品的Ｋ１值为０．９０－１．２０。原油中（２－ＭＨ＋２,３－ＤＭＰ）与（３－ＭＨ＋２,４－ＤＭＰ）占总径（Ｃ４－Ｃ７）的百分比的变化     

Reservoir geochemistry of the Tazhong oilfield in the Tarim Basin, China, Part Ⅰ. Geochemical characteristics and genetic classification of crude oils

According to the assemblage characteristics of saturated hydrocarbon biomarkers in crude oils and their geochemical implications, this study has proposed, for the first time, the criteria for the genetic classification of crude oils in the Tazhong area of the Tarim Basin, China. Crude oils from the area studied are classified as three genetic types: type-Ⅰ is characterized by the low contents of C29 norhopane, extremely abundant contents of gammacerane, low contents of rearranged sterane and relatively high contents of regular C28 sterane; the geochemical properties of type-Ⅱ crude oils are opposite to those of type-Ⅰ crude oils; the parameters for type-Ⅲ crude oils are intermediate between type-Ⅰ and type-Ⅱ. Results of oil correlation indicated that type-Ⅰ crude oils were derived from Cambrian-Lower Ordovician hydrocarbon source rocks, type-Ⅱ curde oils originated from Middle-Upper Ordovician hydrocarbon source rocks and type-Ⅲ crude oils are of mixed origin.     

Reservoir geochemistry of the Tazhong oilfield in the Tarim Basin, China, Part I. Geochemical characteristics and genetic classification of crude oils

1 Introduction Since the 1990’s of the 20th century, oil & gas geochemists have shifted their research focus on hydrocarbon source rocks in the past to that on reservoir rocks and oil reservoirs at present; their research field has been expanded from oil & gas exploration to the assessment of oil reservoirs and production & management. Therefore, reservoir geochemistry as a branch disciplinary of organic geochemistry is now attracting great concern of many oil & gas explorers and oilfield en…     

Compositional characteristics and geochemical significance of light hydrocarbons for crude oils in Tarim Basin, China

Light hydrocarbons, especially C7 isoalkanes, cyclopentanes, cyclohexanes and n-heptane in 540 oils from the Tarim Basin were studied systematically. The results suggested the K1 values [ （2-MH＋ 2,3-DMP）/（3-MH ＋ 2,4-DMP） ] of crude oils vary from a lowest value of 0.78, to a highest value of 1.54, but the K1 values of the majority of oil samples （80%） range from 0.90 to 1.20. However, the absolute contents of （ 2-methylhexane ＋ 2,3-dimethylpentane） and （ 3-methylhexane ＋ 2,4-dimethylpentane） in the total light hydrocarbons （ C4-C7 ） show a similar variation trend. The variation of K1 values of crude oils can suggest a typical sedimentary environment for source rocks. Therefore, according to the compositional characteristics of C7 light hydrocarbons in light of the steady-state catalytic hypothesis, nonmarine oils from the Yingmaili area and marine oils from the Tazhong uplift in the Tarim Basin were genetically classified.     

化探技术在塔里木盆地和准噶尔盆地油气勘探中的应用

中国西部塔里木盆地、准噶尔盆地油气资源丰富,是重要的油气能源基地,也是广泛应用化探技术于油气勘探过程的地区。总结这些地区油气化探的应用效果和成功案例,对现阶段西北地区的油气勘探具有重要的作用和意义。近20年,塔里木盆地、准噶尔盆地陆续取得的油气化探成果,随着两大盆地油气资源的逐步发现,越来越多地得到验证。不仅表明油气勘探中运用化探技术可以带来勘探效益的提高,更证明了在现今勘探难度增大、勘探成本居高不下的形势下,综合勘探技术的成功应用可以缩短勘探周期,提高勘探成功率。     

Migration Fractionation of Neutral Nitrogen Compounds of Crude Oils from Tabei Oilfield in the Tarim Basin, China

The absolute amounts and relative distributions of neutral nitrogen compounds in the Tabei oilfield (e. G. Blocks Ln1-Ln1 1) showed remarkable migration fractionation in the vertical direction. From Ordovician reservoirs (O) to oil legs TⅢ and T Ⅰ of Triassic reservoirs in blocks LN1-LN11, the concentrations of [a] [c] decreased from 1. 59μg/g, 0.49μg/g to 0.17 μg/g (oil). The ratios of various alkylcarbazole isomers, such as 1,8-dimethylcarbazole/nitrogenpartially shielded isomers and 1,8-dimethylcarbazole/nitrogen-exposed isomers, were adopted as the indicators of petroleum migration. The ratios increased from 0.13, 0.20 to 0.67 and from going from the south to the north of the Tabei oilfield, the absolute concentrations of neutral nitrogen compounds decreased drastically, and the nitrogen-shielded isomers were enriched relative to nitrogen-exposed isomers and nitrogen-partially shielded isomers. Crude oils in the Tabei oilfield migrated laterally from the Jilake structure to the Sangtamu fault uplift and Lunnan fault uplift, and crude oils in the same fault uplift migrated and remigrated vertically from Ordovician reservoirs, to oil legs TⅢ to TⅠ of Triassic reservoirs.     

塔里木盆地哈拉哈塘凹陷天然气地球化学特征

哈拉哈塘凹陷位于塔里木盆地塔北隆起中部,具有良好的石油地质条件,是近期油气勘探的重点区带。天然气地球化学特征研究表明,该区天然气干燥系数较低,表现出典型湿气的特征,普遍含有微量的H2S;烷烃气δ13C1和δ13C2值分别为-50.5‰~-42.6‰和-40.2‰~-35.5‰,δD1值介于-262‰~-156‰之间,碳氢同位素系列表现出典型正序特征; C7轻烃组成具有正庚烷优势分布, C5~7轻烃组成以正构和异构烷烃为主。哈拉哈塘凹陷及周缘奥陶系天然气均为海相油型气,既有干酪根裂解气,也有原油裂解气,其中哈拉哈塘天然气中混入了相当比例的原油裂解初期形成的湿气,主要来自于南部阿满过渡带地区的中上奥陶统烃源岩,天然气中具有高δ13C值特征的CO2主要来自碳酸盐岩储层在酸性地层水作用下发生的溶蚀, H2S主要源自含硫化合物的热裂解。其中天然气发生的同位素部分倒转主要源自原油伴生气与原油裂解气的混合。     

Variations in Stable Carbon Isotopic Composition of n-Alkanes from Ordovician- and Triassic-Derived Oils in Lunnan Oilfield, Tarim Basin, NW China: Global Paleoenvironmental Constraints

1IntroductionInthelastdecade,theGC C IRMStechniquehasbeenwidelyappliedinthestudyoffossilfu els (Bjoryetal.,1 990 ,1 991 ,1 992 ,1 994a ,1 994b ;Schoelletal.,1 994) ,biomarkers (Schoelletal.,1 992 )andpaleoenvironment(Pancostetal.,1 999) ,aswellasofpaleoceanography (Kenni cuttetal.,1 990 ) ,biogeochemistry (e .g .Hayesetal.,1 990 )andenvironmentalsciences (O’Malleyetal.,1 994) .Stablecarbonisotopicanalysesweremadeofacoupleofcompound specifictypesincludingn alkanes,isoprenoids,lighthydr…     

Permian bimodal dyke of Tarim Basin, NW China: Geochemical characteristics and tectonic implications

This study reports for the first time the occurrence of bimodal dyke in the Shuigongtuan area of Bachu County, Tarim Basin, NW China. Here, quartz syenite porphyry and diabase dykes occur in direct contact showing bimodal feature. The quartz syenitic porphyry is metaluminous, enriched in K₂O + Na₂O (10–11 wt.%) and total rare earth elements (REE), with low Mg/(Mg + Fe) ratios, high LREE/HREE, and negative Eu anomalies. The chemical characteristics and tectonic discriminative diagrams show that the rocks have geochemical affinity with A-type granites. The diabase dyke shows 45–52 wt.% SiO₂ and Mg/(Mg + Fe) ratio in the range of, with high total REE, high LREE/HREE ratios and lack of Eu anomalies, broadly corresponding to tholeiitic composition. Based on low Y/Nb (as low as 0.4, and less than 1.2), enrichment in LILE and HFSE, and uniform Nb-enrichment patterns in spider diagram for the quartz syenitic porphyry, together with the geochemical patterns of the diabases, this biomodal association is interpreted to be derived from a mantle source and formed under typical within-plate environment. The quartz syenitic porphyry and diabase have Daly gap of 46 wt.%–67 wt.% in SiO₂, which is explained through formation under bimodal rifting. The quartz syenitic dyke probably formed during Early Permian (277 Ma) and has geochemical affinity with the Xiaohaizi syenitic body. We propose that magmas sourced from the mantle intruded into middle–upper crust and were emplaced as dykes, which indicate large-scale extension during the Permian in Tarim Basin. The bimodal dyke has genetic affinity with the huge volume of Permian basalts and igneous rocks (248–292 Ma) that occur in the Tarim Basin. The magmatism manifests the culmination of the major thermal event in the Tarim Basin.