Geophysical prediction of organic matter abundance in source rocks based on geochemical analysis:A case study of southwestern Bozhong Sag,Bohai Sea,China

The Bozhong Sag is the largest petroliferous sag in the Bohai Bay Basin,and the source rocks of Paleogene Dongying and Shahejie Formations were buried deeply.Most of the drillings were located at the structural high,and there were few wells that met good quality source rocks,so it is difficult to evaluate the source rocks in the study area precisely by geochemical analysis only.Based on the Rock-Eval pyrolysis,total organic carbon(TOC)testing,the organic matter(OM)abundance of Paleogene source rocks in the southwestern Bozhong Sag were evaluated,including the lower of second member of Dongying Formation(E_(3)d2L),the third member of Dongying Formation(E_(3)d_(3)),the first and second members of Shahejie Formation(E_(2)s_(1+2)),the third member of Shahejie Formation(E_(2)s_(3)).The results indicate that the E_(2)s_(1+2)and E_(2)s_(3)have better hydrocarbon generative potentials with the highest OM abundance,the E_(3)d_(3)are of the second good quality,and the E_(3)d2L have poor to fair hydrocarbon generative potential.Furthermore,the well logs were applied to predict TOC and residual hydrocarbon generation potential(S_(2))based on the sedimentary facies classification,usingΔlogR,generalizedΔlogR,logging multiple linear regression and BP neural network methods.The various methods were compared,and the BP neural network method have relatively better prediction accuracy.Based on the pre-stack simultaneous inversion(P-wave impedance,P-wave velocity and density inversion results)and the post-stack seismic attributes,the three-dimensional(3D)seismic prediction of TOC and S_(2)was carried out.The results show that the seismic near well prediction results of TOC and S_(2)based on seismic multi-attributes analysis correspond well with the results of well logging methods,and the plane prediction results are identical with the sedimentary facies map in the study area.The TOC and S_(2)values of E_(2)s_(1+2)and E_(2)s_(3)are higher than those in E_(3)d_(3)and E_(3)d_(2)L,basically consistent with the geochemical analysis results.This method makes up the deficiency of geochemical methods,establishing the connection between geophysical information and geochemical data,and it is helpful to the 3D quantitative prediction and the evaluation of high-quality source rocks in the areas where the drillings are limited.

储存条件对总有机碳(TOC)分析校准用蔗糖溶液的影响

为了提高总有机碳(total organic carbon,TOC)分析仪校准用蔗糖溶液定值的准确性,消除影响总有机碳含量的干扰因素,配制拟商业化标准系列溶液,本研究进行了不同水质、不同储存温度、不同材质储存器皿、湿度条件下低浓度蔗糖溶液的稳定性试验和加速实验以及3个批次拟商业化系列标准溶液的组间差异实验。结果显示,超纯水经高压灭菌后TOC含量变化不显著,呈最稳定状态;拧盖广口玻璃瓶储存低浓度蔗糖溶液的最佳温度范围是4~20℃。20℃时,蔗糖溶液中的TOC含量在拧盖聚四氟乙烯(Polytetrafluoroethylene,PTFE)瓶中比在聚丙烯瓶(polypropylen,PP)瓶中更稳定,且与玻璃瓶组无明显差异。加速实验结果显示,在高温(40±2°C)、高湿(75%±5%)条件下储存6个月,PTFE蔗糖溶液的TOC含量无显著变化。此外,随机抽取3个批次的拟商业化溶液并绘制标准曲线,获得了较好重现性和稳定性。通过分析可知,TOC含量会受水质、温度、储存器皿材质及时间等因素影响,选择PTFE能有效减少析出物,提高低浓度蔗糖溶液中TOC含量的稳定性。

Estimation on organic carbon content of source rocks by logging evaluation method as exemplified by those of the 4^(th) and 3^(rd) members of the Shahejie Formation in western sag of the Liaohe Oilfield

One of the most important tasks of evaluating natural resources of petroliferous basins is to determine the organic matter abundance of source rocks in the basin.The usual method for assessing the organic carbon content of source rocks is based on laboratory analyses.There is a deviation in calculating organic carbon content due to the heterogeneous distribution of organic matter and the artificial factors when sampling.According to the continuous characteristics of information logging,the conventional logging curves(mainly acoustics and resistivity,etc.) were calibrated with the organic carbon experimental data of cores,cuttings or sidewall cores.The organic carbon content of source rocks of the 4 th(Es 4) and 3 rd(Es 3) members of the Shahejie Formation in western sag in the Liaohe depression was estimated directly by a great amount of continuous data including resistivity and acoustic logging,etc.Comparison between the results from computer processing and lab analysis of logging data shows that the organic carbon contents derived from the computer processing of logging data have the same reliability and accuracy as the lab analysis results.The present data show that this method is suitable to evaluate the source rocks of western sag in the Liaohe depression and has great potential in evaluating natural resources of sedimentary basins in the future.On the basis of logging data of source rocks,experimental data and existing geochemical analyses of the Liaohe Oilfield,the corresponding total organic carbon(TOC) isograms of source rocks were plotted.The source rocks of Es 4 and Es 3 of the Shahejie Formation are thought to be beneficial to hydrocarbon accumulation due to the high TOC.

Seasonal variations of organic carbon and nitrogen in the upper basins of Yangtze and Yellow Rivers

The profound impacts exerted by climate warming on the Tibetan Plateau have been documented extensively, but the biogeochemical responses remain poorly understood. This study was aimed at seasonal variations of total organic carbon(TOC) and total organic nitrogen(TON) in stream water at two gauging sections(TTH, ZMD) in the upper basin of Yangtze River(UBYA) and at fourgauging sections(HHY, JM, JG, TNH) in the upper basin of Yellow River(UBYE) in 2013. Results showed that concentrations of TON exhibit higher values in spring and winter and lower values in summer. TOC exhibits higher concentrations in spring or early summer and lower concentrations in autumn or winter. Seasonal variations of TOC and TON fluxes are dominated by water flux. In total, the UBYE and UBYA delivers 55,435 tons C of organic carbon and 9,872 tons N of organic nitrogen to downstream ecosystems in 2013. Although the combined flux ofTOC from UBYA and UBYE is far lower than those from large rivers, their combined yields is higher than, or comparable with, those from some large rivers(e.g. Nile, Orange, Columbia), implying that organic carbon from the Tibetan Plateau may exert a potentially influence on regional and/or global carbon cycles in future warming climate.

Initial Litter Chemical Indices as Selection Criteria of Organic Nutrient Resources for Enhancement of Soil Fertility for Smallholder Farmers in Southern Ethiopia

Nutrient release from applied organic nutrient source （ONS） depends on temperature, soil moisture, soil properties, their chemical composition and microbial activity. In order to apply ONS to fulfill the nutrient requirements of plants, knowledge of quality and quantity of chemical constituents of the ONS has paramount importance. Erythrina abyssinica （EA）, Erythrina brucei （EB） and Ensete ventricosum （EV）, the first two being nitrogen-fixing indigenous multipurpose agroforestry trees in Ethiopia, were randomly collected from Southern Ethiopia. The average total nitrogen （TN） contents of EA, EB and EV were 4.05%, 3.35% and 2.56%, respectively. Similarly, the mean total soluble polyphenolics contents were 0.052%, 0.023% and 0.19%, and the mean lignin contents were 9.7%, 12.6% and 6.5%, respectively. In general, these ONS had medium to high TN content. Thus, the ONS can be selected based on their quality, quantity and ratio of their chemical constituents as alternative or supportive organic sources. A ＂decision tree＂ is best fitted for selection of these ONS.

Minerogenetic Mechanism of the Songxi Silver Antimony Deposit of Northeastern Guangdong-Ore-Controlling Role of Organic Matter

Organic geochemistry and comparisons of characteristics of the organic matter in wall rocks of the ore\|controlling strata and ores of the Lower Jurassic Songling black shale formation and the related Songxi silver\|antimony deposit of northeastern Guangdong have been studied in this paper. The results show that the Lower Jurassic Songling shale formation is a suite of biologic\|rich and organic\|rich ore\|bearing marine sedimentary rocks. Micro\|components of the organic matter in the Songling black shale formation consists primarily of algae, amorphous marine kerogen, solid bitumen, and pyrobitumen. The thermal evolution of organic matter is at the over\|maturity stage. There is a general positive correlation between total organic carbon (TOC) and metallogenetic elements such as Ag and Sb in the black shale formation. Organic matter in the host rocks in the Songxi ore deposit played a role in controlling the silver\|antimony depositing environment during the forming process of the black shale ore\|bearing formation. In the absence of vitrinite, the relative level of thermal maturity calculated by solid bitumen reflectance indicates that the ore\|forming temperature of the Songxi silver\|antimony deposit was about 150-170℃, which was considered as an epithermally reworked ore deposit. The roles of organic matter in the formation of the Songxi ore deposit are a primitive accumulation of the metallogenetic elements (Ag, Sb) in the sea\|water cycle system for ore source and a concentration of metals by ion exchange or chelation as well as reduction of the oxidized metals.

Holocene Environmental Climatic Changes Based on Palynofacies and Organic Geochemical Analyses from an Inland Pond at Altitude in Southern Brazil

This paper focuses on the interpretations in the analyses of palynofacies and organic geochemistry carried out on a sedimentary profile covering 9542 cal yr BP from a pond located at the mining district from Ametista do Sul, southernmost Brazil. The hydrological isolation renders this pond, located on a hilltop, highly sensitive to climatic change because the water entering in the system is subsidized exclusively by the rainfall. The main goal of this study is to establish relationships between the sedimentary organic record and climatic fluctuations in the Holocene, trying to correlate the alterations in the particulate organic matter with regional climatic changes or perhaps even events on a global scale. Fluctuations in water depth are inferred from the frequency of the autochthonous elements (algae), which predominate in the basal intervals, but tend to decrease progressively toward the top, when begining to alternate periods of high and low frequency with the parautochthonous (spores) and allochthonous (pollen grains) elements, due to changes in the patterns of moisture. Pseudoschizaea seems to have a closer relationship with the spores than with all other algae and can serve as a biological marker of transitional intervals or have some role in the successional process of vegetation. The variety of spores of ferns and pollen grains on the topmost interval indicates increased vegetal diversity, and is probably related to the process of successional evolution of the area. An increased rainfall event detected between 8.6 to 7.4 ka yr BP can be responsible for the beginning of the process of water accumulation in the gossan and sedimentation of the pond and can be related with the “Bond Events”. The saturation level of the pond, in turn, remained relatively constant until 6.8 ka yr BP, when changes in the patterns of moisture make the environment drier and resulted in an intermittent pattern of water depth, currently existing on the site.

高纯液氨中痕量油分检测方法

介绍了气体中油分检测的多种方法,比较了各方法的原理与适用范围。根据液氨中油分杂质的特性,提出了用总有机碳分析仪对痕量油分进行分析的新方法,该方法检出限为0.0015 mg/kg。液氨中有机碳为0.01~1.0 mg/kg,相对标准偏差为0.29%~4.40%,加标回收率为99.64%~107.14%,可以实现高纯液氨中痕量油分的准确定量。

富有机质页岩TOC含量的地球物理定量化预测

四川盆地涪陵地区页岩气已经实现了工业化开采,而TOC含量是评价页岩有机质丰度和生烃能力的主要参数之一。利用测井资料评价烃源岩TOC含量,能够弥补烃源岩取心少、实测样品分布不连续的不足。为了得到连续的、整体的TOC含量数据,达到对页岩含气层位有机碳含量的定量化预测的目的,以涪陵地区A井为例,从目的层五峰—龙马溪组页岩实测TOC含量出发,结合地球物理测井资料,采用多参数优选、交会分析法、多元回归分析及ΔlgR法寻找与TOC相关性最好的参数,并以此建立区域性的统计学方程。利用该拟合关系式,结合三维地震数据体的叠后反演,计算出TOC数据体。结果显示,预测TOC结果与实测值高度吻合,相关性好,误差小。计算得到页岩目的层位TOC含量为0.5%-5.15%。其中目的层第一段TOC含量为1.9%-5.15%,为优势层段。地震反演得到的TOC连井分布和平面分布特征与研究区4口井的实测与计算TOC值连井对比所表现的分布特征一致。表明用岩石测井密度与TOC关系所预测的TOC分布是准确可信的,此方法可以应用于涪陵地区页岩的勘探评价。

四川盆地东部上二叠统吴家坪组放射虫组合及其烃源意义

四川盆地东部(川东)红星地区上二叠统吴家坪组具备良好的页岩气成藏条件,是四川盆地二叠系页岩气勘探的重要接替领域,但对于该套硅泥质烃源岩的形成机理目前仍缺乏明确的认识。除了岩石矿物组成、地球化学成分、宏体化石组合等特征之外,以放射虫为代表的微体化石对于辨别硅质泥页岩沉积的成因也具有重要意义。放射虫是显生宙海洋浮游生态系统的重要组成部分,其组合可以指示沉积环境,而其丰度是古海洋生产力的良好指标。利用酸蚀法分离出放射虫化石,从而鉴别化石的形态组合特征并结合薄片镜下统计,分析了放射虫丰度与总有机碳(TOC)含量的相关性。研究结果表明,川东红星地区HY3井吴家坪组吴二段中发育大量放射虫化石,经鉴定为泡沫虫目和内射球虫目分子,属于典型的浅水放射虫组合(Se组合)。镜下统计表明吴二段放射虫丰度与TOC含量呈现较好的相关性。通过放射虫组合特征,结合吴家坪组沉积序列和古地理背景,推断吴二段烃源岩形成于水深小于60 m的较浅水环境。吴二段有机质富集可能受到初级生产力、氧化还原条件、陆源碎屑输入、上升流等多方面因素的影响,其中高古生产力是吴二段有机质富集的主控因素之一。

海水中总有机碳(TOC)对牙鲆铜、铅、镉吸收的影响

该文研究了海水中Cu、Pb、Cd浓度分别为0.5mg/L时,总有机碳(TOC)浓度、种类对牙鲆(Paralichthysolivaceus)内脏、肌肉、鳃组织Cu、Pb、Cd蓄积的影响。结果表明:当海水TOC种类相同时,随TOC浓度升高,牙鲆内脏、肌肉、鳃组织Cu、Pb、Cd蓄积量均明显下降;当海水TOC浓度相同时,孔石莼分泌物比牙鲆分泌物更能降低牙鲆各组织Cu、Pb、Cd蓄积量。研究表明:孔石莼、牙鲆分泌物均能降低Cu、Pb、Cd的生物有效性;TOC浓度、种类变化对牙鲆各组织Cu、Pb、Cd蓄积分配均无影响,重金属含量大小顺序均为:内脏>鳃>肌肉。内脏团、肌肉中3种重金属蓄积量大小顺序为Cu>Pb>Cd;鳃中3种重金属蓄积量顺序为Pb>Cu>Cd。

水质TOC分析仪器的现状及其检测技术的新进展

介绍了 TOC检测的基本原理以及其相关仪器的现状 ,包括仪器的方法原理、主要类型、使用标准、仪器型号等。还详细介绍了目前可用于 TOC检测的新技术的发展状况 ,而国际上最新的有关 TOC检测的实验研究也在文章最后进行了阐述。

阳澄湖水体PI、BOD_5与TOC的相关性

采集阳澄湖中湖网围养殖区的下层水样,测定高锰酸指数(PI)、生化需氧量(BOD)5及总有机碳含量(TOC)等水质检测指标,对TOC分别与PI、BOD5的相关性进行分析;并用BOD5/TOC比值作为废水可生化性判定指标,对阳澄湖中湖的水质污染有机物状况进行综合评价。结果显示,阳澄湖水体的TOC与PI、BOD5存在显著的相关性,BOD5与PI、PI与TOC以及BOD5与TOC指标间的相关系数接近或大于0.800,但相关性存在季节变化,在7月高温季节,相关系数均高于0.900,冬季枯水期其相关系数下降至0.800及以下;阳澄湖中湖的BOD5/TOC值为0.48～0.72,平均0.59,各个季节的变化较大,非养殖季节或雨季的BOD5/TOC比值较低,暗示阳澄湖中湖的污染物成分较复杂,除了养殖活动及生活污水造成的有机污染外,工业污染、农业面源污染等占有较大的比例。

湛江特呈岛红树林区底泥TOC的释放研究

以湛江特呈岛红树林区为考察对象,通过底泥TOC向上覆海水释放的模拟对比实验,研究了红树林区底泥中TOC的释放规律和泥水比、温度、pH值三个环境因子对TOC释放的影响,同时对静态和动态体系底泥TOC的释放进行了对比。结果表明,静态下,不同条件释放规律一致,上覆海水TOC的变化呈近似"W"的趋势;泥水比增大会使底泥向上覆海水的TOC释放量增加;温度对底泥TOC释放的影响较为复杂,上覆海水温度较高或较低都有利于底泥TOC的释放;碱性条件有利于沉积物中TOC的释放;海水的运动对沉积物TOC的释放有很好的促进作用。

总有机碳分析仪测定常见水的TOC

水体有机物污染程度的综合指标有CODCr、CODMn、BOD5、TOC等,其中TOC指标是以碳的含量表示水体中有机物总量的综合指标,我国目前尚未将TOC列为常规监测项目,但是TOC作为水体重要指标将越来越受到重视。采集广州地区的常见水样:珠江水、池塘水、河涌水、污水厂进水、污水厂出水各10份用岛津公司的TOC-VCPH型总有机碳分析仪来分析,通过测定样品总碳和无机碳含量,计算二者的差值可得到总有机碳的测定值;用重铬酸钾氧化法(GB11914-89)测定了常见水样的COD。讨论了TOC和COD之间的关系,求出常见水样的COD和TOC一元回归方程,数据表明TOC和COD之间存在比较好的线性关系,可以用TOC指标代替或者计算出COD值。

给水TOC对蒸汽氢电导率的影响

对于采用传统的离子交换除盐系统和全膜处理技术系统生产锅炉补给水的供热机组而言,其影响蒸汽氢电导率的主要因素分别是原水中有机物的残留物和还原性环境中细菌的大量繁殖。将凝胶型阴树脂换成去除有机物效果较好的D213大孔型阴树脂可显著降低传统的离子交换除盐系统出水总有机碳(total organic carbon,TOC);在超滤前后投加非氧化性杀菌剂,均可有效杀灭穿透超滤的细菌。过热蒸汽压力为12.7~18.3MPa和>18.3MPa的锅炉补给水TOC的标准值应分别控制为≤400/Nμg/L和≤200/Nμg/L(N%为供热机组的补水率,N>1)。保证过热蒸汽压力>18.3MPa的汽包炉和直流炉蒸汽质量氢电导率(25℃)标准值合格(氢电导率≤0.10μS/cm)的给水TOC标准值应为≤50μg/L。

测定水质中TOC的分析技术研究进展

水体有机物污染程度的综合指标有COD_(Cr)、COD_(Mn)、BOD_5、TOC等,其中TOC指标是以碳的含量表示水体中有机物总量的综合指标,TOC作为水体重要指标将越来越受到重视。本文对测定水质中TOC的氧化及检测方法进行了阐述和比较,总结了国内外TOC检测方法的研究现状及相关典型产品。

岛津TOC-V_(CPH)分析仪测定养殖废水中的总有机碳

总有机碳(TOC)是以水样中含碳量来表征有机物的含量,是对环境水体中有机物含量的一种估量,也是有机污染的综合指标之一,其作为水体重要指标越来越受到重视。采集天津地区的水产养殖场养殖废水水样,通过测定样品总碳(TC)和无机碳(IC)含量,计算二者的差值可得到总有机碳(TOC)含量。岛津TOC-VCPH分析仪操作简单、灵敏度高、成本较低,可在水产养殖废水的水质监测中应用。

基于变系数ΔlogR技术的烃源岩TOC精细评价

海拉尔盆地乌尔逊凹陷主力烃源岩层(南一段)烃源岩非均质性强,总有机碳(TOC)波动明显,利用有限的测试样品表征整套烃源岩层的生烃潜力具有较强的不确定性;烃源岩层的测井响应表现为高自然伽马、高声波时差、中等电阻率,易于识别,但是烃源岩测井评价参数的通用性差,难以建立起具有普遍适用性的TOC预测公式。针对上述问题,采用变系数ΔlogR技术评价该区烃源岩TOC,将ΔlogR技术中的经验参数视为待定系数,从模型参数地质意义出发,通过针对单井和"分区、分相"预测模型中的待定参数,完成全区120口井TOC测井评价,利用测井计算TOC实现烃源岩分级评价,通过"钻井定频率、层序定展布"的方法,得到南一段不同丰度级别烃源岩的厚度。结果表明,变系数ΔlogR技术预测TOC误差平均为16.6%,比传统方法平均降低19.9%;南一段差烃源岩厚度一般15~20 m,中等烃源岩厚度一般10~20 m,优质烃源岩的厚度一般20~45 m;南一段差烃源岩、中等烃源岩、优质烃源岩的体积分别为0.46×10^(11)、1.08×10^(11)和1.59×10^(11)m^3。

TOC检测技术的新进展及工业应用选型参数

本文介绍了近几年TOC检测技术及其发展,并阐明了主要的两种TOC氧化技术的优劣。