正构二十四烷裂解成气碳同位素动力学模拟及其地质意义

以甲烷的量子化模型及正构二十四烷(n C24)金管限定体系裂解成气实验为基础,从理论上进一步论述了量子化模型应用于重烃气体（乙烷和丙烷）碳同位素动力学模拟的适应性,计算了甲烷、乙烷及丙烷生烃动力学与碳同位素动力学参数, 重点探讨了δ13C2与δ13C3变化的主控因素。研究结果表明, n C24裂解生成的气态烃碳同位素与早期报道的n C18、n C25及原油裂解生成的气态烃碳同位素具有可比性,可应用于地质条件下解释原油裂解气的某些地球化学特征。n C24生烃地质模型表明,其在150～160℃是稳定的,主要裂解温度介于180～200℃之间,与目前所报道的原油裂解地质模型吻合。随热解程度的增加,δ13C2与δ13C3体现了比δ13C1更明显的变化。气藏充注历史控制的同位素累积效应对天然气碳同位素有很大的影响,与累积聚集气相比,阶段聚集气的δ13C变重,并在更大程度上影响了演化曲线的分异。在此基础上,应用n C24裂解成气碳同位素分馏地质模型探讨了塔里木盆地某些油气藏天然气碳同位素值变化的原因。     

现代生物物质生烃机制动力学研究

对浮游藻和底栖藻进行了生烃动力学分析,结合热模拟实验和元素分析研究表明,浮游藻和底栖藻富含S、O、N等杂原子,生烃活化能普遍很低,生烃平均活化能为220 kJ/mol左右,开始生烃活化能小于184 kJ/mol,分别于251 kJ/mol和255 kJ/mol时达到90%生烃转化率,能在未熟、低熟期大量生烃。但浮游藻和底栖藻生烃过程较长,有效生烃（生烃转化率10%～90%）期间活化能跨度较大,分别为59 kJ/mol和71 kJ/mol,生烃温度跨度分别是166.8℃和201.2℃,浮游藻生烃速率快于底栖藻。浮游藻和底栖藻生烃碳转化率是61.77%和34.9%,浮游藻有更强的生烃能力,生烃产物主要是非烃和沥青质,是未熟、低熟油的重要烃源。     

3种无机盐催化热解油页岩

为了发展油页岩催化热解方法,本文对油页岩中干酪根在催化剂（SnCl₂,MoCl₅,ZnCl₂）作用下的热解转化进行了研究。运用傅里叶变换红外光谱（FT-IR）、X射线衍射（XRD）、热重（TG）分析等手段对样品在较低温度下（350℃）热解前后的半焦产物进行了分析,利用Coats-Redfern方法计算了热解后的残余半焦动力学参数。结果表明,催化剂可以使干酪根在350℃发生热解反应,同时也能够降低残余半焦的活化能,其中SnCl₂、MoCl₅和ZnCl₂催化处理后残余半焦的活化能分别降低15.10、10.66和20.58 kJ/mol。     

Early Cooling History of Eclogites from the Dabie-Sulu Orogen: Constraints from Diffusion Kinetics of Garnet

For the first time, we apply different geospeedometric models to garnet zoning patterns that were obtained in this study from detailed EMP analyses for garnets from eclogites and granulite in the Dabie-Sulu orogen. Various zonings of cation diffusion were preserved in the garnets, enabling the acquirement of average cooling rates for the high-to ultrahigh-pressure rocks without using geochronological approaches. The coesite-bearing hot eclogites yield fast cooling rates of about 20 to 30℃/Ma subsequent to peak metamorphic temperatures, whereas the cold eclogite gives a relatively slow cooling rate of 8℃/Ma at its initial exhumation. A very slow cooling rate of <0.3℃/Ma is obtained for the granulite at Huangtuling, suggesting that the granulite may not be involved in the continental deep subduction.     

渤海湾盆地渤中凹陷下第三系烃源岩生烃史

渤海湾盆地渤中凹陷主要发育有两套烃源岩:Es₃烃源岩与Ed₂烃源岩。由于该区地处海域,埋藏较深,对成烃史一直较少涉及。应用生烃动力学方法,对该凹陷沉积中心及斜坡带烃源岩生烃史进行了模拟计算。结果表明,该凹陷中心Es₃生油岩主生油期出现在20～14Ma,主生气期出现在15～10Ma;Ed₂生油岩主生油阶段出现在10～5Ma,目前仍处在主生气阶段。该凹陷斜坡带Es₃生油岩主生油期出现在10～5Ma,目前仍处在主生气阶段,Ed₂生油岩尚处在主生油阶段。结合渤中凹陷储盖组合及运聚、圈闭条件,本研究认为目前在该凹陷及其周围发现的油气藏主要来源于该凹陷10Ma以后生成的油气,油源区主要是斜坡带Es₃与Ed₂生油岩,而凹陷中心烃源岩主要对天然气藏有一定贡献。     

基于等转化法及多元非线性拟合的高岭石非等温脱羟基动力学分析

采用Netzsch STA409PC同步热分析仪研究了苏州高岭石(KW125)在30℃~1 200℃间的热分解过程。采用"Netzsch Thermokinetics software"软件对其脱羟基机理进行了非等温动力学研究。基于等转化法评价了反应活化能及反应进程的依存关系。基于多元非线性拟合确定了最可能反应机理及动力学参数。研究结果表明:苏州高岭石在30℃~1200℃温度范围的热分解为脱羟基与相转变等两个阶段。其脱羟基(30℃~800℃)过程中活化能呈现三个变化:197.68 kJ/mol±12.95 kJ/mol→181.04kJ/mol±18.98kJ/mol→269.7kJ/mol±14.64kJ/mol。脱羟基反应遵循三步连续反应模型t:f,f;(D3-Fn-Fn),一个三维扩散(D3)反应,然后是两个n序列(Fn)反应。第一步,f(α)=3(1-α)^2/3/(2(1-(1-α)^1/3),E1=185.27 kJ/mol,logA=10.83s^-1;第二步,f(α)=(1-α)^n,n=1.75,E2=187.81 kJ/mol,logA=10.32s^-1;第三步,f(α)=(1-α)^n,n=4.4,E3=262.70 kJ/mol,logA=13.26s^-1。     

Synthesis of In‐House Produced Calibrated Silver Phosphate with a Large Range of Oxygen Isotope Compositions

The large range of stable oxygen isotope values of phosphate‐bearing minerals and dissolved phosphate of inorganic or organic origin requires the availability of in‐house produced calibrated silver phosphate of which isotopic ratios must closely bracket those of studied samples. We propose a simple protocol to synthesise Ag₃PO₄ in a wide range of oxygen isotope compositions based on the equilibrium isotopic fractionation factor and the kinetics and temperature of isotopic exchange in the phosphate–water system. Ag₃PO₄ crystals were obtained from KH₂PO₄ that was dissolved in water of known oxygen isotope composition. Isotopic exchange between dissolved phosphate and water took place at a desired and constant temperature into PYREX? tubes that were placed in a high precision oven for defined run‐times. Samples were withdrawn at desired times, quenched in cold water and precipitated as Ag₃PO₄. We provide a calculation sheet that computes the δ¹⁸O of precipitated Ag₃PO₄ as a function of time, temperature and δ¹⁸O of both reactants KH₂PO₄ and H₂O at t = 0. Predicted oxygen isotope compositions of synthesised silver phosphate range from ?7 to +31‰ VSMOW for a temperature range comprised between 110 and 130 °C and a range of water δ¹⁸O from ?20 to +15‰ VSMOW.     

Petrological constraints on the eclogite- and blueschistfacies metamorphism and P-T-t paths in the Western Alps*

Phase relationships in the model mafic system and geothermobarometry allow discrimination of four main groups of high-P rocks in the nappes of the Western Alps: very high-P eclogite-facies (including kyanite eclogites and coesite-pyrope assemblages), eclogite-facies (paragonite-zoisite eclogites), high-T blueschist-facies (glaucophane-garnet ± lawsonite assemblages) and low-T blueschist-facies (glaucophane-lawsonite ± pumpellyite assemblages). The blueschist-facies-eclogite-facies transition is promoted chiefly by increasing T, low bulk X_Mg and relatively low μ_H2O. The variety of assemblages and the heterogeneous approach to equilibrium observed in the Alpine rocks are not only constrained by the intersection of the reaction surfaces in P-T-X space, but also by the effect and timing of the processes which control kinetics (i.e. pervasive deformation and fluid infiltration). The faster rate of dehydration reactions relative to hydration reactions along with the fact that different bulk compositions crossed the reaction curves at different temperatures (and times), all may have induced μ_H2O gradients and contributed to the heterogeneous distribution of deformation through a process of reaction-enhanced ductility. Also mass-transfer may have been an effective process in determining the type of high-P assemblage in particular rock volumes. As regards the P-T-t paths, only the post-climax histories are recorded well in the Alpine nappes. Post-eclogitic exhumation paths at decreasing temperatures characterize structurally higher nappes which were first subducted during the early-Alpine (Cretaceous) event. In contrast, more or less isothermal decompression paths characterize structurally deeper nappes formed by westward propagation of the underthrust surfaces during the early-Alpine event and the subsequent meso-Alpine (Palaeogene) collision between the ‘European’and ‘African’plates. In the Western Alps, prevalent eclogite-facies conditions were attained during the metamorphic climax of the early-Alpine subduction, while blueschist-facies recrystallization characterizes the early-Alpine exhumation of the eclogitized units and the subsequent intracontinental underthrusts linked to the meso-Alpine continental collision.     

鄂尔多斯盆地北部古岩溶储层流体-岩石系统孔隙发育规律及成岩圈闭定量预测

在化学动力学及热力学、流体动力学和弥散动力学等理论的基础上,建立古岩溶储层岩溶斜坡地质模型和数学模型,对模型的承压流、潜流模式流体岩石系统进行动力学模拟研究,得出岩溶斜坡剖面上孔隙发育带和孔隙充填带的有利区,并探讨形成成岩圈闭的形成机理、模式和有利部位。