成熟度与热模拟产物分步萃取对滞留油生物标志物的影响

明确抽提过程中不同极性有机溶剂对所获得的生物标志物参数的影响,对基于生物标志物的生烃母质研究具有重要意义。选用鄂尔多斯盆地延长组低熟富有机质泥页岩进行生、排烃热模拟实验,并结合热模拟固体残样的实测随机镜质体反射率(R_O)值,准确剖析热演化程度和溶剂极性对生源和沉积环境参数适用范围的影响。结果表明：有机溶剂极性的大小不仅会影响抽提物的产率和族组分特征,而且会显著影响抽提物中正构烷烃、三环萜烷的分布特征,但对甾烷的分布特征影响并不明显。溶剂极性和热演化的双重影响导致生物标志物参数的适用范围存在明显区别,∑C_21^-/∑C_22⁺和(nC₂₁+nC₂₂)/(nC₂₈+nC₂₉)仅在低熟—高成熟的中期阶段(R_O值介于0.70%～1.48%之间)可作为有效的生源参数,而沉积环境判识参数∑三环萜烷/∑藿烷值适用范围更窄,仅在低熟—高成熟早期阶段(RO值介于0.70%～1.34%之间)有...     

开鲁盆地钱家店凹陷姚家组砂岩中烃类地球化学特征及来源探讨

对开鲁盆地钱家店地区下白垩统姚家组砂岩中吸附烃和包裹体烃类进行色谱—质谱测试,分析了它们的地球化学特征,并讨论其可能的来源。吸附烃和包裹体烃生物标志物成熟度参数,C₂₉ααα甾烷20S/(S+R)、C₃₁αβ藿烷22S/(S+R)比值基本达到平衡值,显示含矿砂岩中的烃类已接近成熟—成熟热演化阶段;物质来源及沉积环境参数,ααα20R甾烷百分含量C₂₇>C₂₈29,C₂₅/C₂₆三环萜烷、规则甾烷/17αC_29-33藿烷比值显示相对低值,结合伽马蜡烷指数、C₃₅升藿烷指数等参数,综合反映了其来源应为弱氧化—还原环境下的腐殖—腐泥型湖相有机质。这些特征与该凹陷侏罗系九佛堂组烃源岩地球化学特征相似,因而,油源可能来自九佛堂组烃源岩。      

鄂尔多斯盆地三叠系长8储集层致密与成藏耦合关系——来自地球化学和流体包裹体的证据

采用物理压碎、酸液处理与分步抽提相结合的方法,对储集层样品中不同赋存状态的烃类进行分离;再利用气相色谱-质谱联用仪进行组分分析,并结合包裹体均一温度、荧光光谱分析,研究了各类烃之间的关系及充注期次。结果表明,鄂尔多斯盆地三叠系延长组长8含油砂岩中存在4种不同赋存状态的烃类,即游离烃、封闭烃、碳酸盐胶结物包裹体烃以及长石与石英包裹体烃。其中,游离烃的含量在抽提物中占绝对优势,平均为93.4%。包裹体烃荧光光谱λ_(max)、QF_(535)和Q——(650/500)等参数对比分析表明,长石、石英、碳酸盐胶结物包裹体烃成熟度依次增大,其中长石和石英中包裹体烃的荧光光谱各项参数数值相近,而与碳酸盐包裹体烃差异较大。C_(29)ββ/(αα+ββ)与C_(29)20S/(20S+20R)值和甲基菲比值对比分析表明,长石与石英包裹体烃、碳酸盐胶结物包裹体烃、封闭烃、游离烃的热演化程度呈现依次增高的趋势,且游离烃与封闭烃的热演化程度相近。成岩序列、热演化程度分析等综合研究认为长8油藏是一个连续成藏过程,该过程包括3期主要充注,其中晚期充注代表了主成藏期,储集层具有先致密后成藏的特征。     

渤海湾盆地牛庄洼陷南斜坡油砂烃来源分析

对渤海湾盆地东营凹陷牛庄洼陷南斜坡不同埋深油砂及其相邻烃源岩的分析表明,埋深<2700m的油砂烃化学组成与相邻沙四段页岩抽提物有显著差异,两者不具相关性,油砂中的烃类主要为深部的运移烃。油砂烃具有常规油的气相色谱特征,而未熟-低熟页岩在高碳数部位有一明显的甾萜类等高分子量化合物未分辨鼓包,且正构烷烃奇偶优势明显;油砂烃含高丰度的"地质型"甾烷,而未熟-低熟页岩中C₂₉甾烷αββ20S含量甚微,但热稳定性低的化合物5β(H)甾烷及13α(H),14α(H)-三环萜烷含量较高;油砂烃几乎不含甲藻甾烷,而未熟-低熟页岩中含丰富的此类化合物。由深至浅,油砂烃成熟度依次降低,伽玛蜡烷相对含量增高,升藿烷"翘尾"现象变得明显。油砂烃的成熟度梯度及烃类组成的规律性变化不仅可以指示油气运移的大致方向,而且揭示出不同演化阶段烃源岩的生烃特征有别和/或油气运移过程中未熟-低熟烃源岩沥青的混合作用。      

塔北哈6井油砂及沥青砂岩抽提物的地球化学特征及对比

采集塔里木盆地哈拉哈塘凹陷哈6井石炭系油砂及志留系沥青砂岩样品共5件,对其抽提并进行稳定碳同位素、饱和烃气相色谱及色谱/质谱等分析。石炭系油砂与志留系沥青砂岩抽提物的稳定碳同位素组成十分相似;CPI值为0.95~1.06,OEP值为0.94~1.00,姥鲛烷/植烷值为0.34~0.76;C21/C23三环萜烷为0.37~0.47,C29/C30藿烷为0.91~0.97,C35S/C34S藿烷为0.91~1.00,伽马蜡烷/C30藿烷为0.69~0.79,Ts/(Ts+Tm)为0.39~0.43,C27、C28、C29规则甾烷及芴、硫芴、氧芴的相对组成均非常接近。样品抽提物中正烷烃和类异戊二烯烃与25-降藿烷系列化合物和UCM鼓包共存。分析认为石炭系与志留系原油源自相同的烃源岩,两者均存在多期充注且遭受了不同程度的生物降解作用。     

松辽盆地东岭区块烃源岩成熟度

松辽盆地东岭区块烃源岩抽提物具有饱和烃质量分数大、非烃＋沥青质质量分数小、碳同位素较轻的特征。利用GC／MS技术对烃源岩抽提物分析,结果为：饱和烃馏分中C29甾烷立体异构体比值、三降藿烷Ts/Tm比值、C31藿烷22S／（22S＋22R）表明东岭区块烃源岩达到热演化平衡值。芳烃馏分的色谱分布特征、甲基菲指数、4-／1-MDBT和2,4-／1,4-DMDBT比值等参数都表明泉头组烃源岩处于中等成熟度,营城组和上侏罗统火石岭组烃源岩处于较高成熟度。     

渤海湾盆地东濮凹陷北部页岩油富集类型和烃类组成特征——以文410井古近系沙河街组三段为例

为研究渤海湾盆地东濮凹陷北部页岩油的含油性及烃类组成特征,对文410井古近系沙河街组三段岩心样品开展了冷冻热解、三维定量荧光、气相色谱—质谱、岩石薄片等分析测试。东濮凹陷北部沙三段主要发育夹层型和裂缝型2种页岩油富集类型,烃类赋存主要为粒间孔和微裂缝2种形式,有效孔缝组合是页岩油高效富集的关键;岩心样品抽提物烃类组成特征主要以低碳数正构烷烃为主,C₂₇—C₂₈—C₂₉规则甾烷呈“V”型分布,反映出有机质来源主要为陆生高等植物与低等水生生物;伽马蜡烷含量较高,较低的Pr/Ph比值,反映该区有机质沉积环境主要为咸化的还原环境;结合C₃₁22S/(22S+22R)、Ts/(Ts+Tm)、C₂₉ααα20S/(20S+20R)、C₂₉ββ/(αα+ββ)等参数,表明烃源岩处于成熟阶段。      

塔里木盆地北部跃参地区奥陶系原油地球化学特征

塔里木盆地北部跃参地区奥陶系原油具有低粘度、低含硫、低凝固点、高含蜡特征,族组分中总烃含量、饱芳比均较大,非烃+沥青含较低;原油碳同位素较轻,各族组分均小于-28‰。轻烃以正构烷烃占优势,C_7轻烃中正庚烷含量较高,原没最大生成温度为118.94~123.46℃。正构烷烃为单峰-前峰型分布,正构烷烃保存较完整,CPI值为0.98~1.11,Pr/Ph值为0.93~1.12,C_(27)~C_(29)规则甾烷呈"V"字形态分布,C_(29)甾烷含量高于C_(27)甾烷,C28甾烷相对含量小于20%。三环萜烷系列具有较高含量,C_(23)三环萜烷呈主峰态,C_(21)/C_(23)三环萜烷值为0.52~0.59,三环萜烷/藿烷值为2.21~7.82。原油具有硫芴优势,硫芴相对含量65.88~85.88%,根据地化参数估算出R0为,综合分析为高成熟油。跃参与哈拉哈塘、英买力及塔河地区奥陶系原油具有相似的地球化学特征,具有亲源性;生标参数与星火1井寒武系烃源岩相似,分析认为原油主要源于寒武系-下奥陶统烃源岩。     

烃源岩排烃的模拟实验研究

本文对黄县褐煤、茂名油页岩进行了热模拟实验。根据对模拟实验的产物分析,取得了一些认识:①排出烃的nC_(21)~-/nC_22~ 比残留烃要高。甾萜烷,尤其是C_(27)/C_(29)甾及C_(29)萜烷、C_(30)萜烷的βα/αβ值具有较大的差异。相对于其他多环芳烃,低分子量的萘系列、联苯系列、芴系列被优先排出。重质芳烃组分如芘、(艹屈)系列、荧蒽系列则难于运移;②通过对不同温阶残留烃与排出烃的纵向对比研究,发现随排烃量的增加,它们之间的差别变小。     

生物降解稠油中沥青质热模拟实验

对准噶尔盆地西北缘正常原油和严重生物降解稠油中沥青质在不同温度下热模拟产物的生物标志化合物进行了对比分析,结果表明,300℃是较为理想的热模拟温度,在这种条件下,稠油沥青质热模拟产物中生物标志化合物的组成分布与正常原油较为一致,其生物标志化合物组成完整,未遭受生物降解,可用于严重降解油的油源分析,主要表现为:Pr/nC_(17)值和Ph/nC_(18)值相对偏高(分别为0.66~0.71和1.01~1.21),Pr/Ph值相对较低(1.15~1.21),伽马蜡烷指数相对较高(0.30~0.41),反映母质沉积环境为弱还原—还原的半咸水—咸水环境;三环萜烷以"C_(20)C_(21)C_(23)"模式分布,C_(23)三环萜烷/(C_(30)藿烷+C_(23)三环萜烷)值为0.46~0.49;Ts和C_(29)Ts相对含量极低,与典型风城组烃源岩的生物标志化合物分布特征基本一致。     

BIOMARKER GEOCHEMISTRY OF CRUDE OILS AND NEOGENE BITUMINOUS SHALES IN THE YENIKÖY AREA,EREĞLI‐ULUKIȘLA BASIN,CENTRAL ANATOLIA,TURKEY

In the Ere?li‐Uluk??la Basin, southern Turkey, crude oil shows have been observed in the subsurface in the shale‐dominated non‐marine Upper Miocene – Pliocene succession. Based on analyses of samples from four boreholes, the shales’ organic matter content, thermal maturity and depositional characteristics are discussed in this study. Geochemical correlations are established between shale extracts and a crude oil sampled from the shale succession. The shales have moderate to high hydrogen index (HI) and very low oxygen index (OI) values. Pyrolysis data show that the shales contain both Types I and II kerogen, and n‐alkane and biomarker distributions indicate that organic matter is dominated by algal material. Very high C₂₆/C₂₅ and C₂₄/C₂₃, and low C₂₂/C₂₁ tricyclic terpane ratios and C₃₁ R/C₃₀ hopane, C₂₉/(C₂₈+C₂₉) MA and DBT/P ratios in shale extracts indicate that deposition occurred in a lacustrine setting. High gammacerane and C₃₅ homohopane concentrations and low diasterane/sterane ratios with a very low Pr/Ph ratio suggest that both the shales and the source rocks for the oil were deposited in a highly anoxic environment in which the water column may have been thermally stratified. Although the shales analysed have very low T_max values, the production index is quite high which suggests that the shales are early‐mature to mature. Biomarker ratios including C₃₂ 22S/(22R+22S) homohopanes, C₂₉ 20S/(20R+20S) and ββ(ββ+αα) steranes, moretane/hopane, TA(I)/TA(I+II) and MPI‐3 all suggest that the shales are within the oil window. Heavy components of free hydrocarbons (S₁) within the shales may have been recorded as part of the Rock‐Eval S₂ peak resulting in the low T_max values. The oil and shale extracts analysed are similar according to their sterane and triterpane distributions, suggesting that the oil was generated by the shales. However burial depths of the Upper Miocene – Pliocene shale succession are not sufficient for thermal maturation to have occurred. It is inferred that intense volcanism during the Pliocene – Pleistocene may have played an important role in local maturation of the shale succession.     

开鲁盆地陆西凹陷原油地球化学特征

开鲁盆地陆西凹陷是辽河外围盆地中勘探程度最高、发现油藏最多的地区。通过原油样品的精细地球化学分析,研究了陆西凹陷包1块和包14块原油的成熟度、生源输入和沉积环境特征。陆西凹陷包1块和包14块原油具有相似的地球化学特征:Pr/Ph小于0.6;甾烷分布以C₂₉甾烷为主;三环萜明显小于五环萜,三环萜/五环萜比值小于0.15,三环萜以C₂₃为基峰,五环萜以C₃₀为基峰,Ts/Tm在0.7~1.0左右,含有一定量的γ蜡烷。但二者也有一定差异,包14块成熟度略高;正构烷烃分布包1块多以C₂₀为基峰,包14块多以C₂₁为基峰;包1块C_15-21/C_22-28比值比包14块高;包1块具有较高的γ蜡烷指数,指示沉积时较强的盐度环境;包1块藿烷/甾烷比值较低,可能反映藻类比较发育和高盐度对细菌的抑制作用。      

松辽盆地西部斜坡油砂油地球化学及生物降解特征

松辽盆地中央坳陷原油向盆地边缘运移过程中发生降解，在西部斜坡形成油砂矿藏，油砂油密度和黏度大、不流动。在运移方向上，套保-小太平山-西北沟-图牧吉地区的上白垩统姚家组油砂油随深度变浅饱和烃和芳香烃含量减少，非烃和沥青质含量增加，全油和饱和烃碳同位素变重，以上参数在小太平山单井样品中随深度变浅呈相反变化趋势。气相色谱质谱分析发现，油砂油降解级别为Wenger 2~8级，大多数样品饱和烃中正构烷烃和类异戊二烯烷烃缺失，藿烷部分降解，小太平山地区发现25-降藿烷；套保-图牧吉地区随深度逐渐变浅，生物降解程度逐渐增加，三环萜烷/五环三萜烷、C₂₇重排甾烷/规则甾烷、二苯并噻吩/菲等生物标志化合物参数均呈规律性变化。小太平山地区，25-降藿烷和其对应藿烷的质量分数、二者的比值，均反映出生物降解程度随深度变深而增加，藿烷抗降解能力随碳数的增加而增加，升藿烷22R构型抗降解能力大于22S构型。松辽盆地西部斜坡油砂油降解的规律是：由深部厌氧环境向地表喜氧环境运移的过程中，油砂油降解程度逐渐增大，单井样品中随深度和含水饱和度的增加降解程度逐渐增大。     

GEOCHEMICAL CHARACTERISTICS AND THERMAL MATURITY OF OILS FROM THE THRACE BASIN (WESTERN TURKEY) AND WESTERN TURKMENISTAN

Crude oils in the Thrace Basin (western Turkey) and western Turkmenistan are believed to have been generated by a common Oligocene siliciclastic source rock. This widespread source rock extends over the area between western Turkey and the eastern South Caspian Basin. Oils from three Eocene reservoirs in the Thrace Basin and from four Pliocene reservoirs onshore western Turkmenistan were analyzed to investigate and compare their source-rock characteristics. In order to understand controls on the timing of hydrocarbon generation and source-rock maturation in both basins, the results of quantitative basin modelling were compared with those of geochemical analyses.
The results indicate that all the oil samples exhibit similar geochemical characteristics, such as IP13-IP20 acyclic isoprenoid, terpane, regular sterane, methylsterane, and dinosterane profiles. The low tricyclic/pentacyclic terpane ratios, low C₂₉ norhopane/C₃₀ hopane ratios and low diasterane/regular sterane ratios, and the presence of 18α (H)³⁰ oleanane and gammacerane further support a common source or source facies. Based on these observations, it is concluded that shallow-marine clastics of Oligocene age constitute source rocks in both basins.
The oils are of low maturity (Req(%) < 0.60), as indicated by their low ethylcholestane 20S/20S+20R, 17α (H), 21β (H)-bishomohopane 22S/22S+ 22R, and high 17β (H), 21α (H) moretane/17β (H), 21α (H) hopane ratios. However, oils from west Turkmenistan appear to be more mature than those from the Thrace Basin. This is consistent with their earlier generation, which resultedfrom the higher sedimentation rate and higher heating rate. Present-day reservoir depths and temperatures appear to play only a minor role in determining the oils' maturities.     

GEOCHEMISTRY AND ORIGIN OF UPPER CRETACEOUS OILS FROM THE TERMIT BASIN,NIGER

Crude oil samples (n = 16) from Upper Cretaceous reservoir rocks together with cuttings samples of Upper Cretaceous and Paleogene mudstone source rocks (n = 12) from wells in the Termit Basin were characterized by a variety of biomarker parameters using GC and GC‐MS techniques. Organic geochemical analyses of source rock samples from the Upper Cretaceous Yogou Formation demonstrate poor to excellent hydrocarbon generation potential; the samples are characterized by Type II kerogen grading to mixed Types II–III and III kerogen. The oil samples have pristane/phytane (Pr/Ph) ratios ranging from 0.73 to 1.27, low C₂₂/C₂₁ and high C₂₄/C₂₃ tricyclic terpane ratios, and values of the gammacerane index (gammacerane/C₃₀hopane) of 0.29–0.49, suggesting derivation from carbonate‐poor source rocks deposited under suboxic to anoxic and moderate to high salinity conditions. Relatively high C₂₉ sterane concentrations with C₂₉/C₂₇ sterane ratios ranging from 2.18–3.93 and low values of the regular steranes/17α(H)‐hopanes ratio suggest that the oils were mainly derived from kerogen dominated by terrigenous higher plant material. Both aromatic maturity parameters (MPI‐1, MPI‐2 and R_c) and C₂₉ sterane parameters (20S/(20S+20R) and ββ/ (αα + ββ)) suggest that the oils are early‐mature to mature. Oil‐to‐oil correlations suggest that the Upper Cretaceous oils belongs to the same genetic family. Parameters including the Pr/Ph ratio, gammacerane index and C₂₆/C₂₅ tricyclic terpanes, and similar positions on a sterane ternary plot, suggest that the Upper Cretaceous oils originated from Upper Cretaceous source rocks rather than from Paleogene source rocks. The Yogou Formation can therefore be considered as an effective source rock.     

塔里木盆地S74井稠油热模拟实验研究(一)——模拟产物地球化学特征

对塔里木盆地S74井稠油开展了热模拟实验,对原油、模拟残渣抽提物、排出油的族组分及其碳同位素进行了测试,并对饱和烃进行了气相色谱与气相色谱—质谱分析,同时进行了烷烃气碳同位素分析。研究表明:1)模拟残渣抽提物饱和烃结构组成、甾萜烷生物标志化合物随模拟温度的变化具较大幅度的变化,而排出油除在350℃出现异常外,饱和烃结构组成、甾萜烷生标特征随模拟温度的变化不大;2)模拟残渣抽提物及其馏分碳同位素随模拟温度的增高而逐渐变重,而排出油及其馏分碳同位素随模拟温度的变化规律不明显;3)烷烃气碳同位素随模拟温度的增高而逐渐变重,各模拟温度点烷烃气碳同位素呈正常组合序列分布。      

鸡西盆地下白垩统煤系烃源岩生物标志物地球化学特征

应用气相色谱和色谱—质谱等分析方法,对鸡西盆地下白垩统煤系烃源岩的泥岩和煤岩生物标志物进行研究。结果表明,泥岩正构烷烃为前高单峰型,主峰碳为C₁₆或C₁₈,Pr/Ph分布于1.16-2.90,Pr/nC₁₇大于1;煤岩正构烷烃为后高单峰型,主峰碳为C₂₃或C₂₂,Pr/Ph分布于2.86-11.22,Pr/nC₁₇为2.1-3.33;泥岩和煤岩OEP和CPI值集中在1.0附近,已进入成熟阶段。生标中泥岩三、四环萜烷/C₃₀藿烷比值为2.37-3.62,C₃₁22S/22(S+R)值为0.57-0.61,Ts/Tm为0.47-0.81,γ-蜡烷/C₃₀藿烷为0.11-0.34之间,规则甾烷内ααα20R构型呈"V"型分布,母质来源以水生生物为主,形成于还原环境,沉积介质咸化程度高,有利于有机质的保存和转化;煤岩三、四环萜烷/C₃₀藿烷比值低于泥岩,C₃₁22S/22(S+R)值在0.6附近,Ts/Tm和γ-蜡烷/C₃₀藿烷值极低,规则甾烷ααα20R构型分布呈反"L"型,母质来源以高等植物为主,形成于氧化环境,经历了较强的降解作用。      

渤海湾盆地沧东凹陷古近系孔二段页岩层系原油地球化学特征

利用原油物性、族组分分离与定量、饱和烃色谱—质谱、芳烃色谱—质谱、稳定碳同位素等分析测试资料,系统分析了渤海湾盆地沧东凹陷古近系孔二段页岩层系原油地球化学特征。研究表明,原油属于中质、中凝稠油,流动性较差;原油中烃类含量偏低,饱芳比和非沥比均较低。不同构造单元上的原油生物标志物及稳定碳同位素分布特征相似,反映其母质来源及生烃演化过程基本一致。饱和烃色谱以正态分布的单峰型为主,轻碳优势不明显,C27、C28、C29规则甾烷呈"上升型"分布,三环萜烷含量低,反映原油有机母质来源具有湖相水生生物和陆源高等植物的双重贡献,且以陆源高等植物为主。伽马蜡烷指数、重排霍烷含量及分布、Pr/Ph、三芴系列化合物、原油稳定碳同位素分布等指标反映了原油形成于弱氧化—还原条件下的淡水—微咸水沉积环境。正构烷烃分布特征和奇偶优势比、αββ/(ααα+αββ)C29与20S/(20S+20R)C29甾烷异构化指数以及霍烷异构化指数均指示原油成熟度偏低。     

南襄盆地泌阳凹陷西部稠油地化特征及意义

精细刻画稠油地球化学特征,对其油源对比、成因乃至开发都具有一定指导作用。南襄盆地泌阳凹陷西部地区原油均遭受了中等以上级别的生物降解,规则甾烷和藿烷受到不同程度破坏,使得一些反映原油成因、成熟度的常用指标严重失效。通过对该区12个稠油样品地球化学特征的精细分析和研究,发现饱和烃中的伽马蜡烷、Ts、Tm以及长链三环萜烷的抗降解能力高于规则甾烷和藿烷,能较好地反映该区稠油地球化学特征。油源对比表明,该区核三下段原油均来源于核三下段烃源岩,而核三上段原油除来源于核三上段烃源岩外,不同小层段都有核三下段源岩不同程度的贡献。结合芳烃组成特征和参数,可以清楚地将研究区稠油划分成两类,并显示他们可能具有不同的生物降解机制。