工业革命以来青藏高原与南极冰芯高分辨率甲烷记录对比研究

自工业革命以来全球大气CH4含量呈快速的增长趋势, 但达索普冰芯记录所显示的北半球中低纬度地区大气CH4增长的启动时间要晚于极地冰芯记录近100 a. 由于受北半球人类活动CH4排放、CH4在大气中的寿命及大气中CH4的传输等过程的影响, 最近150 a以来, 中低纬度大气CH4与南极大气CH4含量在不同的时段表现出不同的净积累量和增长速率, 且20世纪两次世界大战期间达索普冰芯记录明确显示出人类活动排放的减缓使大气CH4呈负增长. 对比研究认为, 到20世纪中叶人类活动的甲烷排放已达到极高值, 中低纬度大气中CH4增长率及年积累逐步趋于平稳且略有降低. 可以认定, 工业革命以来中低纬度地区大气CH4与南极大气CH4含量的变化在不同的时段在受控于人类活动影响的同时, CH4在大气中的行为和传输过程以及东亚中低纬度季风气候的影响决定了两地之间大气CH4含量变化存在显著的差异.     

Formation of H2 and CH4 by weathering of olivine at temperatures between 30 and 70°C

Hydrocarbons such as CH4 are known to be formed through the Fischer-Tropsch or Sabatier type reactions in hydrothermal systems usually at temperatures above 100°C. Weathering of olivine is sometimes suggested to account for abiotic formation of CH4 through its redox lowering and water splitting properties. Knowledge about the CH4 and H2 formation processes at low temperatures is important for the research about the origin and cause of early Earth and Martian CH4 and for CO2 sequestration. We have conducted a series of low temperature, long-term weathering experiments in which we have tested the CH4 and H2 formation potential of forsteritic olivine.The results show low temperature CH4 production that is probably influenced by chromite and magnetite as catalysts. Extensive analyses of a potential CH4 source trapped in the crystal structure of the olivine showed no signs of incorporated CH4. Also, the available sources of organic carbon were not enough to support the total amount of CH4 detected in our experiments. There was also a linear relationship between silica release into solution and the net CH4 accumulation into the incubation bottle headspaces suggesting that CH4 formation under these conditions could be a qualitative indicator of olivine dissolution.It is likely that minerals such as magnetite, chromite and other metal-rich minerals found on the olivine surface catalyze the formation of CH4, because of the low temperature of the system. This may expand the range of environments plausible for abiotic CH4 formation both on Earth and on other terrestrial bodies.     

长江中下游六省大气甲烷柱浓度时空分布

甲烷(CH4)是造成气候变暖的主要温室气体之一。为了了解长江中下游水稻种植区CH4浓度的分布情况,本次研究基于温室气体观测卫星(greenhouse gases observing satellite,GOSAT)和大气红外探测仪(atmospheric infrared sounder,AIRS)卫星反演的数据产品,对我国长江中下游六省大气CH4柱浓度的时空分布特征进行了研究。研究结果表明,由GOSAT反演的长江中下游六省大气CH4浓度呈逐年增长趋势,其年均浓度由2011年的1817×10^?9增长至2018年的1875×10^?9,高于东三省、华北平原和全国平均水平。区域平均年增长量为8.2×10^?9 a^?1。各省年际增长幅度略有差异,纬度偏低的江西、湖南和浙江三省大气CH4浓度高且增长量偏大,纬度偏高的湖北、安徽和江苏三省大气CH4浓度略低且增长量偏小。长江中下游六省大气CH4呈现较强的季节变化特征,湖北、湖南、江西和浙江峰值出现在9月,安徽、江苏峰值出现在8月。垂直方向上长江中下游六省CH4浓度随气压降低,浓度逐渐减小,呈现出明显的季节变化特征,近地面层GOSAT反演的最高值出现在夏季,最低值出现在春季;高层最高值出现在秋季,最低值出现在春季。AIRS反演的大气CH4浓度空间分布上北高南低,与GOSAT反演结果不一致,可能由于AIRS主要反映了对流层中层大气状况而GOSAT更多的反映了近地面层大气CH4的变化。其垂直方向上呈现高度越高,浓度越低,不同高度上秋季浓度均最高。     

澳大利亚纳沃日金矿流体混合与金的成矿作用

流体包裹体研究表明，纳沃日金矿成矿脉体中流体包裹体类型有三种，富CH4、CH4－CO2－H2O和富H2O包裹体。初始成矿流体是富CH4热液，在主矿化阶段，另一来源的CO2－H2O流体与CH4流体发生了不均匀混合，并且在石英－磁黄铁矿阶段最为强烈，造成不同矿化部位的xCH4变化极大，早期近于纯CH4流体被充分“稀释”后，石英－黄铁矿阶段的xCH4显著减小，到成矿晚期只剩CO2－H2O流体。正是由于不同性质流体的混合，造成热液的pH及fo2的升高，流体中的金－硫络合物分解，金沉淀成矿。     

Methane Adsorption on Montmorillonite,Kaolinite and Illite at High Pressures

Shale gas, which is derived from organic matters in shale and stored in shale deposits, is an important unconventional gas resource and attracts attention due to its significant requirement in the hydrocarbon production. Methane (CH4) is the dominant component of shale gas, and adsorbed gas is an important reservoir form. Many studies have investigated the adsorption capacities and adsorption mechanisms of CH4 in shale. Organic matters and clay minerals have been proposed to be the two major components for CH4 adsorption. Adsorption of CH4 in organic matters, such as the adsorption capacity and effects of characteristics of the organic matters, has been well investigated. However, studies on CH4 adsorption on clay minerals have mainly focused on evaluating the adsorption capacity, and very little information about the adsorption mechanism has been provided. For example, the adsorption sites and factors influencing CH4 adsorption on clay minerals remain unclear. Three main reasons account for this: (1) the co-existence of organic matters in samples affects the evaluation of CH4 adsorption on clay minerals; (2) the pressures used during adsorption are not representative of actual reservoir pressures; and (3) the clay minerals selected have low swelling capacity and a smaller interlayer distances than a CH4 size, resulting in the misunderstanding of the CH4 adsorption sites.     

水田和旱地土壤氧化甲烷的温度响应

为了探讨温度对农耕区土壤氧化CH4的影响,文中分别采用2种旱地（吉林暗棕壤和河北潮土）和2种水田土壤（江西水稻土和安徽水稻土）样品进行了4个温度下（5、15、25和35℃）氧化高浓度CH4的模拟实验研究。结果表明,4种土壤氧化高浓度CH。的最佳温度为25～35℃,除江西水稻土外,其余土壤在5和15℃没有表现出氧化高浓度...     

南海神狐海域天然气水合物注热降压开采数值模拟研究

针对南海神狐海域天然气水合物成藏条件,利用pT+H软件和水平井技术对天然气水合物的注热和注热降压开采效果进行了模拟分析。重点讨论了注入热水温度为30、60、90℃时水合物饱和度以及CH4气体饱和度、CH4产气率、累积CH4产气量和产水量的变化规律,发现两种开采模式下水合物低饱和度分布范围随时间增长和温度升高而增大;CH4产气率在开采10 d内升高较快,之后逐渐减小。模拟结果表明:注热降压开采模式比单纯注热模式的效果有较大改善,而且温度对于提高CH4产气量效果不明显,但因为天然气水合物藏的低渗透性,神狐海域的天然气水合物的CH4产气量不大。研究结果可为南海神狐海域和类似地区天然气水合物开采提供参考。     

羊东井田瓦斯块段划分及影响因素分析

根据羊东井田2号煤层钻孔煤样瓦斯成份、含量及分布特征,以F1断层为界,以北为瓦斯稳定地段,以南至F6、F19断层为瓦斯异常地段。区内大量数据表明,在稳定地段内随煤层埋深增加,CH4含量较大,CO2含量减少;异常地段内由西向东CH4含量降低,CO2含量增高。CH4、CO2含量主要影响因素之一是断层,具有明显挤压特征的断层附近CH4含量高,张性断裂附近CH4含量低,CO2含量高;之二是岩浆活动,岩浆岩与碳酸盐接触分解出大量CO2,遇到断层后CO2沿裂隙由深部向浅部运移,造成断裂附近煤层中CO2含量增加。根据CH4浓度,井田东南边界的F19断层区段为CO2-N2带,向西北部渐变为CH4带。     

CH4-H2O体系流体包裹体拉曼光谱定量分析和计算方法

CH4—H2O体系流体包裹体研究对含油气盆地流体分析和成矿流体研究都有重要的意义。本文详细介绍了H2O、CH4和CH4—H2O体系的拉曼光谱特征及分子作用,分析了CH4—H2O体系热力学特征,同时对CH4—H2O体系流体包裹体拉曼光谱定量分析和计算的方法及步骤进行了叙述。利用人工合成流体包裹体建立甲烷浓度与拉曼特征峰面积比值之间的校正曲线是实现CH4—H2O体系流体包裹体定量分析的基础。盐度对包裹体定量分析的影响最为显著,在恒定甲烷浓度下,甲烷与水的拉曼峰面积比值随着盐度增加而减少。对于流体包裹体封闭体系,随温度升高,液相甲烷浓度增大。校正曲线必须包含对温度和盐度的校正。石英主矿物性质和方位对甲烷浓度定量分析的影响可以忽略。实验研究表明,原位拉曼光谱技术是准确获取流体包裹体中甲烷水合物生成条件的一种有效方法。因此,基于拉曼光谱分析和显微测温分析结果,采用热力学模型可以定量计算CH4—H2O体系流体包裹体的相关参数。     

Discovery and Significance of High CH4 Primary Fluid Inclusions in Reservoir Volcanic Rocks of the Songliao Basin, NE China

Comparing compositions of the fluid inclusions in volcanic rocks to the contents and isotopes of the gases in corresponding volcanic reservoirs using microthermometry, Raman microspectroscopy and mass spectrum analysis, we found that： （1） up to 82 mole% methane exists in the primary inclusions hosted in the reservoir volcanic rocks; （2） high CH4 inclusions recognized in the volcanic rocks correspond to CH4-bcaring CO2 reservoirs that are rich in helium and with a high ^3He/^4He ratio and which show reversed order of 813C in alkane; （3） in gas reservoirs of such abiotic methane （〉80%） and a mix of CH4 and CO2, the enclosed content of CH4 in the volcanic inclusions is usually below 42 mole%, and the reversed order of δ^13C in alkane is sometimes irregular in the corresponding gas pools; （4） a glassy inclusion with a homogeneous temperature over 900℃ also contains a small portion of CH4 although predominantly CO2. This affinity between gas pool and content of inclusion in the same volcanic reservoirs demonstrates that magma-originated gases, both CH4 and CO2, have contributed significantly to the corresponding gas pools and that the assumed hydrocarbon budget of the bulk earth might be much larger than conventionally supposed.     

油气藏埋存二氧化碳生物转化甲烷的机理和应用研究进展

埋存CO<,2>生物转化CH<,4>技术是利用油、气藏中内源微生物,以埋存的CO<,2>为底物,通过CO<,2>生物还原途径合成CH<,4>的生物技术.此技术因兼备CO<,2>减排的环保意义、生物合成CH<,4>的再生能源意义、延长油气藏寿命和潜在经济收益等优势有着广泛应用前景.CO<,2>的捕集、埋存和油气藏生物多样...     

石漠化治理对土壤中CO2、CH4变化特征及碳汇效应的影响

为探究石漠化治理对土壤中CO2、CH4变化特征及碳汇效应的影响,采用气相色谱法对重庆市南川石漠化治理示范区土壤中CO2、CH4浓度进行观测,结合土壤温度、土壤含水率、土壤容重和土壤有机碳对石漠化治理区（试验区）和对比区（未经过石漠化治理的荒草地）进行研究,并用溶蚀量数据估算岩溶区碳汇量。结果显示:土壤中CO2浓度随土壤深度的增加先增加后减小,变化范围为393～7 400 mg·L-1;而土壤中CH4浓度随土壤深度的增加先减小后增大,变化范围为1.13～3.42 mg· L-1。试验区土壤中CO2浓度均值为2 131 mg· L-1,CH4浓度均值为1.94 mg· L-1 ;而对比区土壤中CO2浓度均值为2 338 mg· L-1,CH4浓度均值为2.10 mg·L-1。土壤温度、土壤有机碳与土壤中CO2浓度变化趋势呈显著正相关关系,而与土壤中CH4变化趋势呈显著负相关关系,说明土壤温度和土壤有机碳是影响土壤中CO2、CH4浓度的主要因素;土壤温度与土壤中CO2浓度呈正相关关系且相关性随石漠化治理而变弱,说明经过石漠化治理土壤温度对土壤中CO2浓度的影响减弱。试验区岩溶试片溶蚀速率大于对比区,且经过石漠化治理,由岩溶作用产生的碳汇可提高0.66～9.42 t·km-2·a-1 ;说明石漠化治理对于岩溶区碳汇起到了促进作用。      

控制灌溉对稻田CH4和N2O综合排放及温室效应的影响

采用静态箱-气象色谱法对控制灌溉稻田CH₄和N₂O排放进行了观测,研究控制灌溉模式对稻田CH₄和N₂O排放的影响,并对其温室效应进行了评估。结果表明,控制灌溉稻田CH₄排放通量明显低于淹水灌溉稻田,且主要集中在分蘖前期和中期,全生育期CH₄排放量比淹水灌溉稻田减少73.2%～85.0%。控制灌溉稻田N₂O排放通量在水稻全生育期大部分时间都要大于淹水灌溉稻田,稻季N₂O排放量分别为106.65 mg/m2和96.40 mg/m2,控灌稻田较淹灌稻田增加了10.6%。控制灌溉稻田稻季排放CH₄和N₂O的全球增温潜势(GWPs)为726 kg/hm2,较淹水灌溉稻田减少了59.1%。控制灌溉模式能显著降低CH₄和N₂O综合排放的全球增温潜势。     

煤及显微组分在超高温开放体系实验中动力学参数确立与天然气形成过程预测

通过对塔里木盆地煤及其显微组分以1K/min升温速率在开放体系下进行热模拟实验(Tmax=1200℃),确定了CH4与N2生成动力学参数。根据化学反应动力学原理,当煤岩生成CH4和N2为25个一级平行反应且具有相同频率因子(Ao=1.0×1013s-1)时,生成CH4与N2每个反应对应的活化能可以通过实验数据与理论计算拟合,获得Gaussian型活化能分布特征为:CH4在活化能为42～90kcal/mol内,煤、镜质组、壳质组、丝质组和半丝质组生成CH4的主频活化能分别为60、52、50、70和66kcal/mol;N2在活化能为60～108kcal/mol内,其主频活化能分别为74、108、100、108和102kcal/mol。根据这些实验动力学参数,推测了煤岩在地质升温速率为5.3K/Ma时CH4的转化率:CH4在地质温度为20℃时开始形成;当地质温度为160℃时,煤岩中CH4已生成总量的80%。镜质组和壳质组CH4转化率要高于煤岩。     

箱隔式拦河闸的抗冻胀研究与实践

传统的中小型拦河闸受冻害破坏较普遍而严重，新型的箱隔式拦河闸通过其总体布置，结果形式本身圆满地解决了复杂的冻害问题，不需外加任何特殊的防冻措施，箱隔式闸总体布置简单，阵线集中，薄弱环节少，受冻部位及面积小，基础在一个平面上均用水保温防冻，消除了基底法向冻胀力的危害，箱隔对称水平冻胀力大部分通过箱隔传递作用而衰减或平衡。     

东天山香山镁铁-超镁铁岩中富CH4流体包裹体的特征及其意义

香山岩体是东天山镁铁-超镁铁杂岩带的一个典型岩体，相带发育。各相带都含有韭闪石质普通角闪石巨晶，后环绕橄榄石和拉长石生长，构成包橄结构和包含结构，表明母岩浆富水。本研究的样品采自于香山岩体中岩体。拉长石和橄榄石中的流体包裹体孤立分布，或成群分布，大小不等，无明显方向性，或成串分布，平行于寄主矿物的颗粒边界和生长晶面。流体包裹体主要为原生，一部分为次生或假次生，是在以角闪石结晶为标志的岩浆流体大量出溶期间捕获的，因而代表了岩浆源区的流体。运用显微激光拉曼光谱仪，在100～4000cm。全波段范围内对拉长石和橄榄石中的50多个流体包裹体的气泡进行了分析。结果表明，流体包裹体的气体成分分为4类：a)富CH4气体；b)富H2O气体；c)H2O CH4混合气体；d)多组分(C2H6 N2 CH4，C2H6 CH4 N2 C4H6)混合气体。因而，香山岩体所携带的流体是一种富CH4等还原性挥发份和富H2O的流体。由于上地幔处于相对氧化状态，上地幔的挥发份以CO2为主。因而，香山岩体的母岩浆和流体应该来自于地幔过渡带或软流圈，这同时也表明新疆北部晚古生代的地幔过渡带或软流圈可能是未被氧化的、含C—H系列流体的圈层。俯冲板片的再循环，为地幔深处的H2O提供了来源。富CH4还原性C—H流体和富H2O流体，为地幔深处的熔融发挥了重要作用，进而产生了新疆北部造山后广泛分布的镁铁一超镁铁岩浆以及铜镍硫化物矿床。     

还原性流体与斑岩型矿床成矿机制探讨

目前已经广泛认同斑岩型Cu-Mo-Au矿床是在氧化性相对较高的含矿流体作用下形成的。但是随着研究的深入,逐渐发现了一系列具备还原性特征的斑岩型矿床,这些矿床往往不发育表征高氧逸度的原生磁铁矿和硫酸盐矿物。本文针对目前发现的与还原性I型花岗岩相关的斑岩矿床进行了综合分析,发现此类矿床的成矿流体中普遍含有CH4等还原性流体成分,并且伴生有CO2。结合相关资料分析认为还原性流体中所含有的CH4可能来自邻近的S型花岗岩的混染作用,但也不排除是经地球排气作用从地幔进入到地壳的可能性。结合典型还原性斑岩型矿床研究,给出了一个化学模型,认为CH4和SO2属于岩浆系统自生成分,在特定化学物理阶段发生反应,形成H2S和CO2,从而抑制了硫酸盐矿物的形成。反应所生成的H2S可以与Mo结合形成辉钼矿矿化,而Cu-Au由于在氧逸度较低的环境下具备更高的活性,易于富集在气相流体中,所以可以迁移到某一距斑岩系统较远的有利部位沉淀成矿,从而形成以Mo矿化为核心区,外围Cu-Au矿化的模式。     

胜利油田边缘及外围找寻不同类型深部天然气的可能性

笔者依据对前人资料和本人研究成果的综合分析,提出在胜利油田的边部碱性橄榄玄武岩发育地带找寻无机成因二氧化碳气藏和在油田外围金伯利角砾岩筒或含地幔岩包体的碱性玄武岩火山口附近找寻地球深部来源烃类气藏的建议。     

A blast of gas in the latest Paleocene: simulating first-order effects of massive dissociation of oceanic methane hydrate

Carbonate and organic matter deposited during the latest Paleocene thermal maximum is characterized by a remarkable -2.5% excursion in delta 13C that occurred over approximately 10(4) yr and returned to near initial values in an exponential pattern over approximately 2 x 10(5) yr. It has been hypothesized that this excursion signifies transfer of 1.4 to 2.8 x 10(18) g of CH4 from oceanic hydrates to the combined ocean-atmosphere inorganic carbon reservoir. A scenario with 1.12 x 10(18) g of CH4 is numerically simulated here within the framework of the present-day global carbon cycle to test the plausibility of the hypothesis. We find that (1) the delta 13C of the deep ocean, shallow ocean, and atmosphere decreases by -2.3% over 10(4) yr and returns to initial values in an exponential pattern over approximately 2 x 10(5) yr; (2) the depth of the lysocline shoals by up to 400 m over 10(4) yr, and this rise is most pronounced in one ocean region; and (3) global surface temperature increases by approximately 2 degrees C over 10(4) yr and returns to initial values over approximately 2 x 10(6) yr. The first effect is quantitatively consistent with the geologic record; the latter two effects are qualitatively consistent with observations. Thus, significant CH4 release from oceanic hydrates is a plausible explanation for observed carbon cycle perturbations during the thermal maximum. This conclusion is of broad interest because the flux of CH4 invoked during the maximum is of similar magnitude to that released to the atmosphere from present-day anthropogenic CH4 sources.     

无烟煤对甲烷等温吸附解吸特性实验研究

研究空气干燥基无烟煤对甲烷(CH4)的等温吸附/解吸特性,发现其对甲烷的解吸残余率达56%。为了对其进行深入探讨,特设计了原煤样的炭化和活化实验,扩大了原料的比表面积,进而在等温条件下研究了两个改性样品对甲烷的吸附/解吸特性。对比发现,比表面积的增大能显著增加样品对甲烷的吸附总量,但对解吸残余率没有明显的影响。考虑到影响甲烷吸附/解吸的因素,又在等温条件下对主控因素——水分作了平行实验,结果显示,水分对活化样解吸残余率有明显影响。