Controlling Factors,Accumulation Model and Target Zone Prediction of the Coal‐bed Methane in the Huanghebei Coalfield,North China     

Dawei Lv  Jitao Chen  Zengxue Li  Guiqiang Zheng  Cuiyu Song  Haiyan Liu  Yanru Meng  Dongdong Wang 《Resource Geology》2014,64(4):332-345

The Huanghebei Coalfield, one of the coal production bases in North China, was considered as a coalfield without coal‐bed methane (CBM) during past decades. In recent years, however, CBM has been discovered in coal‐bearing successions. In order to understand the CBM geological characteristics and accumulation process in this area, fifteen coal samples were collected and analyzed with respect to coal maceral and reflectance. The result shows that the gas distribution is uneven and the content varies in different areas even for the same coal bed. The storage of CBM is affected by geological factors such as burial depth, geological structures, and magmatic intrusion, among which the former two are more important in the formation of CBM. Deep burial of coal beds with the presence of cap‐rock mudstone can seal CBM. The CBM is also accumulated and preserved at the place where normal faults are distributed. Magmatic intrusion causes contact metamorphism and controls the CBM formation by heating the coal‐bearing successions. The obtained data indicate the geological conditions in northeastern Zhaoguan Mine are preferable for CBM formation and conservation; recent exploration estimates the CBM geological reserves up to 282.16 Mm³ and average of reserve abundance at 0.1662 × 10⁸ m³ km^?2. The Changqing Mine is a potential prospect in terms of CBM exploration since its geological conditions (structures and burial depth) are similar to the Zhaoguan Mine and its cap rock is even better.  相似文献   

塔中地区奥陶系喜马拉雅山期S干气充注的证据          下载免费PDF全文

何宏  李红霞  张科  陶小晚  蔡春芳 《地质科学》2014,49(4):1327-1336

塔中地区奥陶系天然气成因多样;Ⅰ号坡折带中东部奥陶系天然气以高干燥系数、 甲烷同位素值重为特征;与塔深1井寒武系原油裂解气接近;应主要来自寒武系原油裂解气成因。寒武系贫H₂S、 高成熟原油裂解气在喜马拉雅山期时;气侵奥陶系油气藏;得到了以下主要证据的支持: 1）天然气甲烷δ¹³C值大多比Chung et al.（1988）天然气模式甲烷δ¹³C值计算值高3‰以上;2）干燥系数与甲烷δ¹³C值大体上具有正相关关系;3）天然气干燥系数与H₂S含量大体上具有负相关关系。这些特征表明;存在贫H₂S、 相对富¹³C甲烷为主的干气与富H₂S、 相对贫¹³C甲烷的湿气混合作用。奥陶系中H₂S-δ³⁴S 值为14‰～20‰;远低于中深1井寒武系原地热化学硫酸盐还原作用（TSR）成因的H₂S（33‰）;支持了奥陶系中H₂S并不是来源于寒武系古油气藏。于是提出;来自寒武系贫H₂S的干气在喜马拉雅山期对良里塔格组和鹰山组油气藏发生了气洗;油气藏的气/油比值增大、 导致了原油蜡含量增高、 甲烷δ¹³C值发生正偏移。  相似文献   

Compositional zoning of fluid inclusions in the Archaean Junction gold deposit,Western Australia: A process of fluid ‐ wall‐rock interaction?     

P. A. Polito  Y. Bone  J. D. A. Clarke  T. P. Mernagh 《Australian Journal of Earth Sciences》2013,60(6):833-855

The Junction gold deposit, in Western Australia, is an orogenic gold deposit hosted by a differentiated, iron‐rich, tholeiitic dolerite sill. Petrographic, microthermometric and laser Raman microprobe analyses of fluid inclusions from the Junction deposit indicate that three different vein systems formed at three distinct periods of geological time, and host four fluid‐inclusion populations with a wide range of compositions in the H₂O–CO₂–CH₄–NaCl ± CaCl₂ system. Pre‐shearing, pre‐gold, molybdenite‐bearing quartz veins host fluid inclusions that are characterised by relatively consistent phase ratios comprising H₂O–CO₂–CH₄ ± halite. Microthermometry suggests that these veins precipitated when a highly saline, >340°C fluid mixed with a less saline ≥150°C fluid. The syn‐gold mineralisation event is hosted within the Junction shear zone and is associated with extensive quartz‐calcite ± albite ± chlorite ± pyrrhotite veining. Fluid‐inclusion analyses indicate that gold deposition occurred during the unmixing of a 400°C, moderately saline, H₂O–CO₂ ± CH₄ fluid at pressures between 70 MPa and 440 MPa. Post‐gold quartz‐calcite‐biotite‐pyrrhotite veins occupy normal fault sets that slightly offset the Junction shear zone. Fluid inclusions in these veins are predominantly vapour rich, with CO₂?CH₄. Homogenisation temperatures indicate that the post‐gold quartz veins precipitated from a 310 ± 30°C fluid. Finally, late secondary fluid inclusions show that a <200°C, highly saline, H₂O–CaCl₂–NaCl–bearing fluid percolated along microfractures late in the deposit's history, but did not form any notable vein type. Raman spectroscopy supports the microthermometric data and reveals that CH₄–bearing fluid inclusions occur in syn‐gold quartz grains found almost exclusively at the vein margin, whereas CO₂–bearing fluid inclusions occur in quartz grains that are found toward the centre of the veins. The zonation of CO₂:CH₄ ratios, with respect to the location of fluid inclusions within the syn‐gold quartz veins, suggest that the CH₄ did not travel as part of the auriferous fluid. Fluid unmixing and post‐entrapment alteration of the syn‐gold fluid inclusions are known to have occurred, but cannot adequately account for the relatively ordered zonation of CO₂:CH₄ ratios. Instead, the late introduction of a CH₄–rich fluid into the Junction shear zone appears more likely. Alternatively, the process of CO₂ reduction to CH₄ is a viable and plausible explanation that fits the available data. The CH₄–bearing fluid inclusions occur almost exclusively at the margin of the syn‐gold quartz veins within the zone of high‐grade gold mineralisation because this is where all the criteria needed to reduce CO₂ to CH₄ were satisfied in the Junction deposit.  相似文献   

Holocene initiation and expansion of the southern margins of northern peatlands triggered by the East Asian summer monsoon recession     

《地学前缘(英文版)》2023,14(2):101526

Northern peatlands represent one of the largest biospheric carbon reservoirs in the world. Their southern margins act as new carbon reservoirs, which can greatly influence the global carbon dynamics. However, the Holocene initiation, expansion and climate sensitivity of these peatlands remain intensely debated. Here we used a compilation of basal peat ages across six isolated peatlands at the southern margins of northern peatlands to address these issues. We found that the earliest initiation event of these peatlands occurred after the Younger Dryas (YD, 12,800–11,700 years ago) period. The second initiation event and rapid expansion occurred since 5 ka cal. BP. The recession of East Asian summer monsoon (EASM) during the YD period and at around 5 ka cal. BP likely played a major role in controlling the initiation and expansion of these peatlands. The rapid expansion of these peatlands possibly contributed to the significant increases in atmospheric methane concentrations during the late Holocene because of the minerotrophic fens status and rapid expansion of them. These ecological processes are different from northern peatlands, indicating the special carbon sink and source implications of these peatlands in the global carbon cycle.  相似文献   

煤层气储层岩石物理建模与脆性正演分析     

张钊基  王国伟  邹冠贵 《地质论评》2023,69(Z1):445-446

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春季黄、渤海沉积物中CH4和N2O的垂向分布特征研究     

李思琦  陈烨  尹霞  臧昆鹏  甄毓 《地学前缘》2022,29(5):35-46

本研究分别利用顶空平衡法与qPCR技术测定了2018年春季黄、渤海5个典型站位柱状沉积物中甲烷(CH₄)和氧化亚氮(N₂O)浓度及产甲烷菌与硫酸盐还原菌功能基因拷贝数,并分析了其与间隙水中相关环境因子的关系。沉积物上方水文条件的差异以及其中复杂的碳氮生物地球化学过程使得CH₄和N₂O浓度呈现出明显的空间和垂直变化。结果显示,沉积物中CH₄浓度为0.23~0.92 μmol·kg^-1,N₂O浓度为18.90~104.96 nmol·kg^-1。总体来说,渤海沉积物中CH₄和N₂O平均浓度高于黄海。垂向分布上,CH₄浓度均随深度增加逐渐升高, $\text{SO}_{4}^{2-}$浓度随深度增加逐渐降低,并与CH₄浓度呈镜像关系,产甲烷菌与硫酸盐还原菌的丰度也遵循着同样规律,这表明沉积物中产甲烷作用受$\text{SO}_{4}^{2-}$浓度的抑制。 mcrA基因拷贝数平均值为渤海低于黄海。除3500-7站外,沉积物中mcrA基因拷贝数随深度增加而升高。各站位mcrA 基因丰度与CH₄浓度均无显著相关性,且mcrA丰度与$\text{SO}_{4}^{2-}$浓度之间也未检测到显著相关性。dsrB基因拷贝数远高于mcrA基因拷贝数,且两者相差至少两个数量级。 dsrB基因拷贝数随深度逐渐增加,直至10 cm左右,随后至沉积物底部逐渐减少。各站位dsrB基因拷贝数与CH₄浓度剖面略有镜像关系,但均未检测到显著负相关性。以上结果均表明沉积物中存在着同时消耗沉积物中$\text{SO}_{4}^{2-}$与CH₄的其他作用。N₂O浓度随深度增加先降低,在深度30 cm以下逐渐升高。间隙水中$\text{NO}_{3}^{-}$和$\text{NO}_{2}^{-}$浓度均随深度减小,同时$\text{NH}_{4}^{+}$浓度与其呈相反趋势。沉积物中N₂O与$\text{NO}_{2}^{-}$及$\text{NO}_{3}^{-}$浓度均呈正相关,且前者相关性较高,说明反硝化作用是沉积物中N₂O产生的主要过程。这些结果为进一步了解近岸陆架海域沉积物中CH₄和N₂O的来源、分布及碳氮生物地球化学循环提供了参考资料。  相似文献   

Identification of functionally active aerobic methanotrophs and their methane oxidation potential in sediments from the Shenhu Area,South China Sea     

Jing Li  Chang-ling Liu  Neng-you Wu  Xiao-qing Xu  Gao-wei Hu  Yan-long Li  Qing-guo Meng 《China Geology》2022,5(2):285-292

Large amounts of gas hydrate are distributed in the northern slope of the South China Sea, which is a potential threat of methane leakage. Aerobic methane oxidation by methanotrophs, significant methane biotransformation that occurs in sediment surface and water column, can effectively reduce atmospheric emission of hydrate-decomposed methane. To identify active aerobic methanotrophs and their methane oxidation potential in sediments from the Shenhu Area in the South China Sea, multi-day enrichment incubations were conducted in this study. The results show that the methane oxidation rates in the studied sediments were 2.03–2.36 μmol/gdw/d, which were higher than those obtained by sediment incubations from other areas in marine ecosystems. Thus the authors suspect that the methane oxidation potential of methanotrophs was relatively higher in sediments from the Shenhu Area. After the incubations family Methylococcaea (type I methanotrophs) mainly consisted of genus Methylobacter and Methylococcaea_Other were predominant with an increased proportion of 70.3%, whereas Methylocaldum decreased simultaneously in the incubated sediments. Collectively, this study may help to gain a better understanding of the methane biotransformation in the Shenhu Area.©2022 China Geology Editorial Office.  相似文献   

河南省煤层气钻井技术发展历程及展望          下载免费PDF全文

张晓昂  刘国卫  齐治虎  张留彬  胡向志  王立峰 《探矿工程》2022,49(5):86-93

河南省地勘队伍自2003年开展煤层气钻井施工以来,积极开展技术创新研究,先后研发了大直径绳索取心机具、射流式扩孔掏穴器等专用器具,率先开展了煤层气参数井、水平井、采动井、穿采空井等施工技术研究和实践,形成了涵盖各类煤层气井型的钻井施工技术体系,积累了丰富的实战经验,促进了我国煤层气产业的发展。本文在总结了河南地勘单位在煤层气钻井技术方面取得的成果的基础上,结合国内煤层气开发深度逐渐增加、采空区覆盖面积逐渐增大、构造煤煤层气未实现突破等行业发展需求,提出了开展高效煤层气水平井钻井技术、气动定向钻井技术及构造煤开发钻井关键技术等方面研究的建议。  相似文献   

新疆阜康急斜地层煤层气井施工技术          下载免费PDF全文

石浩  姚宁平  赵洋洋  金新  张铁牛 《探矿工程》2015,42(10):17-20

针对新疆阜康白杨河煤层气矿区地层急斜、软硬互层、存在烧变岩层等问题造成的钻孔极易弯曲、坍塌等问题,采用空气潜孔锤钻井技术及无线电磁波随钻测井定向钻进技术,顺利解决了钻孔弯曲、塌孔、成孔难等施工难题,施工效率达到常规钻井速度的3倍以上,对于类似地层的煤层气井施工有借鉴意义。  相似文献   

利用AIRS产品分析中国地区近地面甲烷浓度时空特性   总被引：1，自引：0，他引：1  

王红梅  李佳田  张莹  李莘莘  张蓝  陈良富 《遥感学报》2015,19(5):827-835

甲烷(CH4)作为仅次于二氧化碳(CO2)的第二大温室气体,不仅在全球和区域尺度光化学反应中起着重要作用,而且在能量收支平衡及气候变化方面有着重要的影响。2013年,Auqa/EOS的大气红外探测仪(AIRS)热红外近地表CH4产品在AIRS Version6.0产品中发布,其结果尚未在中国进行验证,利用热红外传感器分析中国近地表CH4浓度的时空分布还处于初始阶段。本文利用中国青海瓦里关(WLG)、中国台湾鹿林山(LLN)及蒙古乌兰乌勒(UUM)地基观测资料对AIRS V6.0近地面CH4浓度产品进行了验证,误差在2%以内,二者相关系数r分别为0.68、0.5、0.69,变化趋势一致,进而从地域、季节变化和年际变化3个方面探讨了2003年—2013年中国地区近地面CH4浓度的时空分布特征。结果表明:CH4浓度最低值位于西藏地区(1800 ppbv),高值区位于新疆维吾尔自治区北部、内蒙古自治区及黑龙江北部(1920 ppbv);夏季高,冬季低,季节性变化明显,年际变化基本上呈增长趋势。  相似文献