西澳大利亚珀斯盆地页岩气资源研究

珀斯盆地位于澳大利亚西海岸,是西澳大利亚页岩气资源勘探的重点区域。该盆地属于复杂的凹陷裂谷,海相沉积二叠纪的Carynginia组和早三叠世Kockatea页岩层被认为是潜在的含气地层。通过搜集大量外文文献,全面总结了该盆地含气目标层的地物化特征,Carynginia组的总有机碳含量为1%~15%,干酪根为III型,Ro在0.56~1.91;Kockatea页岩层的总有机碳含量为1%~4%,干酪根为II/III混合型,Ro为0.48~1.93。两组共划分了11各岩相段,其中黑色页岩岩相段和含黄铁矿泥岩段是最重要的生烃含气层。综合考虑地层、地化指标和岩石地球物理性质,圈出了可供参考的页岩气甜点区。     

The accumulation of radiocesium in coarse marine sediment: effects of mineralogy and organic matter

The controlling factors affecting the accumulation of (137)Cs in marine sediment have not been investigated in detail, especially in coarse grained sediment. Eighty eight coarse marine sediment samples near Wuljin, Korea, were characterized by quantitative X-ray-diffraction (XRD), gamma-ray, and total organic carbon (TOC) analysis. Those factors were then compared. The grain size was in the range of -0.48 to 3.6Mdphi corresponding to sand grains. TOC content was in the range of 0.06-1.75%, and the concentration of (137)Cs was TOC contents showed even better correlation between biotite content and (137)Cs activity. For the entire samples, however, the TOC content showed better correlation with (137)Cs activity than other single factors, indicating that biotite and organic carbon are the most important factors controlling (137)Cs fixation. The combined effect of biotite and TOC for (137)Cs fixation was also confirmed by multiple regression analysis ((137)Cs activity=1.712.TOC (wt%)+0.202.biotite (wt%)-0.097; R(2)=0.819). The regressed slopes indicated that the (137)Cs-adsorption capacity of TOC was about 8.5 times higher than that of biotite. However, the amount of (137)Cs adsorbed onto biotite was 30% more than that adsorbed onto TOC due to much greater biotite content in the sediment. The role of biotite in fixing (137)Cs becomes more important in sediment with coarser grains, containing little TOC.     

九寨沟箭竹海沉积物中BSi含量及其环境指示意义

通过对九寨沟箭竹海沉积物样品中生物硅( BSi)含量的分析,讨论箭竹海沉积物中BSi含量与总有机碳(TOC)及粒度的关系,进而探讨BSi含量反映自然和人类因素对湖泊水体和沉积物的影响.箭竹海沉积物中BSi含量介于5.5～ 15.8 mg/g之间,BSi含量与TOC呈显著正相关关系.BSi含量还较显著地受到粒度影响,较细颗粒沉积物对BSi有较强的吸附作用.箭竹海沉积物中BSi含量变化与气温波动关系不密切,主要反映了森林砍伐和旅游开发等人类活动对湖泊水体和沉积物的影响.     

InterPreting effects of TOCinert organic content on source rock Potential using S2 vs. TOC graPh in Maamba Coalfield,southern Zambia

The authors Present the effects of the total organic carbon( TOCinert )during Pyrolysis and how it overall affects the estimates of the hydrocarbon index( HI)using the cross Plot S2 vs. TOC graPh. A to...     

Distribution of gamma-ray radionuclides in surface sediments of the Kongsfjorden,Arctic: Implications for sediment provenance

The Kongsfjorden is highly sensitive region to climate variability, however, the study of gamma-ray radionuclides in related areas is relatively scarce. In this study, the grain size, total organic carbon(TOC), 13 Corg isotopes, and specific activities of seven gamma nuclides were analysed in surface sediments of the Kongsfjorden in the Arctic during the summer of 2017. The specific activities of 210 Pbex, 137 Cs, 238 U, 226 Ra, 228 Ra, 228 Th, and 40 K were 12–256 Bq/kg, 0–3.8 Bq/kg, 25–42 Bq/k...     

Holocene evolution of the Indian Summer Monsoon inferred from a lacustrine record of Lake Wuxu,south‐east Tibetan Plateau

A continuous sediment record since 12.3 cal ka bp from Lake Wuxu (south‐eastern Tibetan Plateau) was investigated in terms of the Holocene evolution of the Indian Summer Monsoon. The molar C/N ratio and stable C isotope were used to identify the source of the organic matter as well as climate conditions. The evolution of Lake Wuxu was summarized wihtin two periods. During the first period (early to mid‐Holocene), the lake received increased fluvially transported materials, reflecting variation in the summer monsoon with solar insolation. The lake level declined and water residence time increased because of reduced river discharge during the second period (late Holocene) corresponding to a weakening of the summer monsoon. The organic material revealed a major contribution from lake primary productivity, which showed identical patterns with a high‐resolution isotope record from Dongge Cave, as well as total solar irradiance. Our record from Lake Wuxu indicates that the Holocene evolution of the Indian Summer Monsoon has been driven by the solar forcing at decadal/centennial to millennial time scales. Furthermore, an abrupt decline in the monsoon was detected at around 4.0 cal ka bp , which is probably caused by an increased frequency of EI Nino‐Southern Oscillation events. Copyright © 2019 John Wiley & Sons, Ltd.     

An organic geochemical investigation on organic rich sediments from two Neogene formations in the Klias Peninsula area,West Sabah,Malaysia

Twenty organic rich outcrop samples from the Belait and Setap Shale formations in the Klias Peninsula area, West Sabah, were analysed by means of organic petrology and geochemical techniques. The aims of this study are to assess the type of organic matter, thermal maturity and established source rock characterization based primarily on Rock-Eval pyrolysis data. The shales of the Setap Shale Formation have TOC values varying from 0.6 wt%–1.54 wt% with a mean hydrogen index (HI) of 60.1 mg/g, whereas the shal...     

雅布赖盆地萨尔台凹陷侏罗系新河组有效烃源岩研究

对雅布赖盆地萨尔台凹陷侏罗系新河组有效烃源岩进行有机质下限分析,识别有效烃源岩分布范围,并分析有效烃源岩下限值与成熟度的关系。本文据烃源岩生排烃机理,通过w（TOC）与热解参数w（S₁）之间的关系,确定了雅布赖盆地萨尔台凹陷新河组下段有效烃源岩w（TOC）下限值,其中盐场次凹有效烃源岩w（TOC）下限值为1.0%,小湖次凹w（TOC）下限值为0.7%,梭托次凹不具备排烃条件。利用△log R法计算新河组下段的页岩w（TOC）含量,识别并统计了单井有效烃源岩厚度,参照沉积相和地层厚度确定了有效烃源岩的分布特征,新河组下段有效烃源岩主要分布在小湖次凹中央洼槽带,累计厚度最大约600 m,盐场次凹有效烃源岩累计厚度基本小于100 m,梭托次凹不发育有效烃源岩。成熟度越大,有效烃源岩w（TOC）下限值越小     

下扬子巢湖地区中二叠统孤峰组富有机质硅质岩有机地球化学特征

华南下扬子巢湖地区孤峰组黑色硅质岩中富含有机质，是中国油气和页岩气勘探的潜在源岩，研究孤峰组有机质富集规律对开展油气勘探工作具有重要意义。文章对巢湖平顶山地区中二叠统孤峰组硅质岩进行总有机碳含量（TOC）和饱和烃分子标志物特征分析，探讨其中有机质富集规律。结果表明孤峰组有机质热成熟度参数C29 ααα甾烷20S/(20S+20R)比值分布在0.37 至0.46 之间，C31升藿烷22S/(S+R)比值分布在0.53 至0.59 之间，热成熟度水平处于生油窗的早期。有机质正构烷烃主峰为C18，以短链烷烃为主，藿烷含量较高，甾烷以C27 ααα 20R 胆甾烷为主，有机质主要来自海洋浮游藻类和细菌。孤峰组有机质Pr/Ph 比值小于0.6，伽玛蜡烷指数平均值为0.2，说明古沉积水体为中等分层缺氧环境。孤峰组普遍富含有机质可能与炎热气候下古沉积水体长期分层和缺氧有关。随着气候在孤峰组沉积早期和晚期突然变冷，高强度的海洋洋流上涌提高了初级生产力水平，造成有机质更大规模的富集。