异常地热对烃源岩生烃的影响——以三塘湖盆地辉绿岩侵入体为例

为了探讨异常地热对烃源岩沉积有机质热演化的影响,采集了三塘湖盆地大黑山东剖面附近一辉绿岩侵入体南侧石炭系哈尔加乌组上部黑色泥岩层系的8块样品（W008～W015）,其与辉绿岩岩体的距离分别是20 cm、50cm、100 cm、180 cm、300 cm、500 cm、1 000 cm和1 700 cm,通过分析这八块样...     

Evaluation of the petroleum composition and quality with increasing thermal maturity as simulated by hydrous pyrolysis: A case study using a Brazilian source rock with Type I kerogen

Hydrous pyrolysis (HP) experiments were used to investigate the petroleum composition and quality of petroleum generated from a Brazilian lacustrine source rock containing Type I kerogen with increasing thermal maturity. The tested sample was of Aptian age from the Araripe Basin (NE-Brazil). The temperatures (280–360 °C) and times (12–132 h) employed in the experiments simulated petroleum generation and expulsion (i.e., oil window) prior to secondary gas generation from the cracking of oil. Results show that similar to other oil prone source rocks, kerogen initially decomposes in part to a polar rich bitumen, which decomposes in part to hydrocarbon rich oil. These two overall reactions overlap with one another and have been recognized in oil shale retorting and natural petroleum generation. During bitumen decomposition to oil, some of the bitumen is converted to pyrobitumen, which results in an increase in the apparent kerogen (i.e., insoluble carbon) content with increasing maturation.The petroleum composition and its quality (i.e., API gravity, gas/oil ratio, C₁₅₊ fractions, alkane distribution, and sulfur content) are affected by thermal maturation within the oil window. API gravity, C₁₅₊ fractions and gas/oil ratios generated by HP are similar to those of natural petroleum considered to be sourced from similar Brazilian lacustrine source rocks with Type I kerogen of Lower Cretaceous age. API gravity of the HP expelled oils shows a complex relationship with increasing thermal maturation that is most influenced by the expulsion of asphaltenes. C₁₅₊ fractions (i.e., saturates, aromatics, resins and asphaltenes) show that expelled oils and bitumen are compositionally separate organic phases with no overlap in composition. Gas/oil ratios (GOR) initially decrease from 508–131 m³/m³ during bitumen generation and remain essentially constant (81–84 m³/m³) to the end of oil generation. This constancy in GOR is different from the continuous increase through the oil window observed in anhydrous pyrolysis experiments. Alkane distributions of the HP expelled oils are similar to those of natural crude oils considered to be sourced from similar Brazilian lacustrine source rocks with Type I kerogen of Lower Cretaceous age. Isoprenoid and n-alkane ratios (i.e., pristane/n-C₁₇ and phytane/n-C₁₈) decrease with increasing thermal maturity as observed in natural crude oils. Pristane/phytane ratios remain constant with increasing thermal maturity through the oil window, with ratios being slightly higher in the expelled oils relative to those in the bitumen. Generated hydrocarbon gases are similar to natural gases associated with crude oils considered to be sourced from similar Brazilian lacustrine source rocks with Type I kerogen of Lower Cretaceous, with the exception of elevated ethane contents. The general overall agreement in composition of natural and hydrous pyrolysis petroleum of lacustrine source rocks observed in this study supports the utility of HP to better characterize petroleum systems and the effects of maturation and expulsion on petroleum composition and quality.     

Fishing‐induced evolution of growth: concepts,mechanisms and the empirical evidence

The interest in fishing‐induced life‐history evolution has been growing in the last decade, in part because of the increasing number of studies suggesting evolutionary changes in life‐history traits, and the potential ecological and economic consequences these changes may have. Among the traits that could evolve in response to fishing, growth has lately received attention. However, critical reading of the literature on growth evolution in fish reveals conceptual confusion about the nature of ‘growth’ itself as an evolving trait, and about the different ways fishing can affect growth and size‐at‐age of fish, both on ecological and on evolutionary time‐scales. It is important to separate the advantages of being big and the costs of growing to a large size, particularly when studying life‐history evolution. In this review, we explore the selection pressures on growth and the resultant evolution of growth from a mechanistic viewpoint. We define important concepts and outline the processes that must be accounted for before observed phenotypic changes can be ascribed to growth evolution. When listing traits that could be traded‐off with growth rate, we group the mechanisms into those affecting resource acquisition and those governing resource allocation. We summarize potential effects of fishing on traits related to growth and discuss methods for detecting evolution of growth. We also challenge the prevailing expectation that fishing‐induced evolution should always lead to slower growth.     

煤中干酪根的成熟度与菲的吸附行为间的关系

将云南先锋褐煤采用热模拟的实验方法制得一组成熟度不同的煤,并将煤中的干酪根用于对菲的吸附研究.结果表明:随着干酪根成熟度的增加,有机质结构变得紧密、刚硬,还原性和芳香性增强.不同成熟度干酪根的内部结构和性质与菲的吸附行为间存在一定的关系.随着干酪根内部结构的刚性和芳香性的增强,吸附等温线的非线性逐渐增强.对于成熟度相对较低的干酪根,随着成熟度的增加,吸附容量逐渐增大,而对于成熟度相对较高的干酪根,随着成熟度的增加,吸附容量却减小.     

压力对有机质成熟和油气生成的影响

沉积盆地中流体压力在地质历史中是变化的,所以很难确定压力对油气生成,有机质成熟作用的影响,高压模拟实验是研究压力效应的常用方法,但不同研究者采用不同的实验方法所得出的结论也各有不同,一些地质实测的研究则表明,压力增加可能会抑制或延迟油气的生成和有机质成熟。介绍了有关压力效应的不同观点,并提出压力效应研究中应进一步开展的内容及其意义。     

Sonophotocatalysis of endocrine-disrupting chemicals

Sonolysis and photolysis often exhibit synergistic effects in the degradation of organic molecules. An assay of fish oocyte maturation provides an appropriate experimental system to investigate the hormonal activities of chemical agents. Oocyte maturation in fish is triggered by maturation-inducing hormone (MIH), which acts on receptors on the oocyte surface. A synthetic estrogen, diethylstilbestrol (DES), possesses inducing activity of fish oocyte maturation, and a widely used biocide, pentachlorophenol (PCP), exhibits a potent inhibitory effect on fish oocyte maturation. In this study, the effects of the combined treatment by sonolysis with photolysis (sonophotocatalysis) to diminish the hormonal activity of DES and the maturation preventing activity of PCP was examined. By sonophotocatalysis, hormonal activity of DES was completely lost within 30min and the inhibiting activity of PCP was lost within 120min. These results demonstrated that sonophotocatalysis is effective for diminishing the endocrine-disrupting activity of chemical agents.     

断裂对辽河西部凹陷大洼油田油气成藏和分布的控制作用

位于辽河西部凹陷的大洼油田属于多断块油田,受大洼断裂带的影响,不同断块不同油层的原油性质和化学组成有较大差异,并且浅层原油成熟度高于深层原油的成熟度。这些差异反映断层在不同时期的活动对油气运移和分布产生的作用不同。大洼主干断裂是一个基底断裂,是一个古近纪长期活动的生长断裂,它控制着清水洼陷的沉积;在始新世形成的断层成为沙三段烃源岩向东营组地层供烃的油源断层;在东营组末以来形成的断层为控制东营组油气分布的控藏断层。断层多期活动以及烃源岩排烃动力的幕式变化导致大洼油田不同深度油层的油气成熟度垂向分布“颠倒”。不同时期烃源岩排烃动力的变化与东营组地层内不同砂体孔渗性的差异,导致油气进入储层时的动力和阻力的差异也是大洼油田油气水分布复杂的可能原因。     

吐哈盆地侏罗系煤成液态烃生成演化的热模拟实验研究

利用绝对密闭式干热解方法对吐哈盆地侏罗系腐殖煤的液态烃生成演化规律进行了研究。研究结果表明,煤在低成熟阶段(R_0=0.40％～0.65％)的液态烃产率变化幅度较小、地球化学特征也保持未熟—低熟特征;热解物产率曲线在R_0=0.58％～0.59％阶段呈现一个低谷;液态烃大量生成于R_0=0.65％阶段,产率峰值出现于R_0=1.09％阶段。进一步通过热模拟产物Pr/Ph、Pr/nC_(17)、Ph/nCl_(18)及饱/芳值等参数的变化规律、热解物正构烷烃分布特征、热模拟残渣的热解色谱特征,及与典型煤成油进行对比研究.证实了侏罗系煤成液态烃主要生成并排驱于成熟阶段(R_0=0.65％～1.09％)。