共查询到20条相似文献，搜索用时 31 毫秒
1.
JU Yiwen JIANG Bo HOU Quanlin WANG Guiliang & NI Shanqin . College of Mineral Resource Geosciences China University of Mining Technology Xuzhou China . Laboratory of Computational Geodynamics College of Geosciences Graduate School of Chinese Academy of Sciences Beijing China 《中国科学D辑(英文版)》2005,48(9):1418-1437
13C nuclear magnetic resonance (NMR) is widely used for research of solid fossil energy (i.e., coal, kerogen)for three reasons. First, the spectrum and data are directly obtained from the samples; second, the samples are not destroyed during analysis, and third, multi-structure information on carbon, hydrogen and oxygen functional groups can be collected quantita- tively and semi-quantitatively. During the past 20 years, the NMR method has been used to study many aspects of coal structure [1… 相似文献
2.
Shen Boheng Shen Shuzhong Wu Qiong Zhang Shuichang Zhang Bin Wang Xiangdong Hou Zhangshuai Yuan Dongxun Zhang Yichun Liu Feng Liu Jun Zhang Hua Shi Yukun Wang Jun Feng Zhuo 《中国科学:地球科学(英文版)》2022,65(6):983-1011
Science China Earth Sciences - The Carboniferous-Permian strata in the North China Block (NCB) contain abundant fossils, coals and natural gases. Establishing a high-resolution timescale for the... 相似文献
3.
The genetic relationships between microenvironment of the Late Paleozoic peat-forming swamp and the sulfur contents of coal
in North China have been studied by using coal-facies parameters involving gelification degree, tissue preservation index,
vegetation index, transportation index, groundwater influence index, water medium indicator and swamp type index, etc. Among
the various controlling factors of swamp microenvironment, swamp water medium elaborates a dominant action to sulfur accumulation
in the marine-influenced coals; while coal-forming plant type, hydrodynamic state and water covering depth are more important
to sulfur accumulation in the fresh water-influenced coals. Geological fractionation of sulfur isotopes reflects that sulfur
accumulation experienced multi-stages evolution. Pyrite sulfurs formed earlier than organic sulfur and the sulfur isotopic
δ34Sp shows lower values than organic sulfur isotopic δ34So. In the brine-influenced coals, sulfur accumulation processed relatively a long time span, the distribution of sulfur isotopes
dispersed, and the coals are provided with high sulfur contents. In the fresh-water-influenced coals, sulfur accumulation
occurred mainly at the syngenetic-penesyngenetic stage and the early diagenetic stage, and the total sulfur is lower and mainly
composed of organic sulfur. 相似文献
4.
The physical characteristics of coal reservoirs are important for evaluating the potential for gas desorption, diffusion, and seepage during coalbed methane (CBM) production, and influence the performance of CBM wells. Based on data from mercury injection experiments, low-temperature liquid nitrogen adsorption, isothermal adsorption, initial velocity tests of methane diffusion, and gas natural desorption data from a CBM field, herein the physical characteristics of reservoirs of high-rank coals with different coal-body structures are described, including porosity, adsorption/desorption, diffusion, and seepage. Geometric models are constructed for these reservoirs. The modes of diffusion are discussed and a comprehensive diffusion-seepage model is constructed. The following conclusions were obtained. First, the pore distribution of tectonically deformed coal is different from that of normal coal. Compared to normal coal, all types of pore, including micropores (<10 nm), transitional pores (10–100 nm), mesopores (100–1000 nm), and macropores (>1000 nm), are more abundant in tectonically deformed coal, especially mesopores and macropores. The increase in pore abundance is greater with increasing tectonic deformation of coal; in addition, the pore connectivity is altered. These are the key factors causing differences in other reservoir physical characteristics, such as adsorption/desorption and diffusion in coals with different coal-body structures. Second, normal and cataclastic coals mainly contain micropores. The lack of macropores and its bad connectivity limit gas desorption and diffusion during the early stage of CBM production. However, the good connectivity of micropores is favorable for gas desorption and diffusion in later gas production stage. Thus, because of the slow decline in the rate of gas desorption, long-term gas production can easily be obtained from these reservoirs. Third, under natural conditions the adsorption/desorption properties of granulated and mylonitized coal are good, and the diffusion ability is also enhanced. However, for in situ reservoir conditions, the high dependence of reservoir permeability on stress results in a weak seepage of gas; thus, desorption and diffusion is limited. Fourth, during gas production, the pore range in which transitional diffusion takes place always increases, but that for Fick diffusion decreases. This is a reason for the reduction in diffusion capacity, in which micropores and transitional pores are the primary factors limiting gas diffusion. Finally, the proposed comprehensive model of CBM production under in situ reservoir conditions elucidates the key factors limiting gas production, which is helpful for selection of reservoir stimulation methods. 相似文献
5.
煤储层应力敏感性是影响煤层气井产能的地质因素,以鄂尔多斯盆地东南缘高煤级煤储层为对象,通过煤样的应力敏感性实验和现场测试,建立了高煤级煤储层渗透性与应力之间的相关关系和模型;探讨了渗透性变化的控制机理.研究结果表明, 煤储层渗透率随应力的增加按负指数函数规律降低.在应力小于5 MPa时,煤储层渗透率随应力增加快速下降,应力敏感性最强;应力在5~10 MPa时,渗透率随应力增加而较快下降,应力敏感性较强;而当应力大于10 MPa后,渗透率随应力的增加下降速度减缓,应力敏感性减弱.与沁水盆地南部高煤级煤样实验结果对比认为,鄂尔多斯盆地东南缘山西组2煤层应力敏感性要小于沁水盆地南部山西组3煤层的应力敏感性.煤储层渗透性是在应力作用下煤储层中裂隙产生压缩(压密)变形,裂隙开度急剧减小的结果.因此在煤层气开发过程中控制排采速度,尤其是排采早期降液速度,对于防止煤储层应力敏感性,提高采收率具有实际意义. 相似文献
6.
Laser Raman spectroscopy of organic matter in coals and sedimentary rocks has been increasingly investigated to assess thermal maturity. Pure organic matter such as vitrinite and solid bitumen, as well as isolated kerogen are definitely selected for this purpose, but there has been no systematic report on the Raman spectral parameters directly based on mineral-organic aggregations(MOA) in shales. In this paper, the Raman spectral characteristics and parameters of MOA in two sets of marine shale samples from southern China with either different TOC contents(TOC=0.10–4.59%) or different maturities(BRo=1.71–4.57%) were investigated. It was found that the Raman technique is very sensitive to the organic matter in MOA. As the TOC content of the shales reaches about 0.60%, perfect Raman spectra with D and G bands derived from organic matter in MOAwere obtained, and the Raman parameters of MOA are in good agreement with those of its associated solid bitumen, and can indicate the thermal maturity just like those of solid bitumen. Using the Raman parameters of MOA is a potential alternative way to estimate maturity levels of high and over mature shales, especially those lower Paleozoic and Precambrian shales that lack macerals suitable for reflectance or Raman measurements. 相似文献
7.
The detailed lithospheric structure of South China is the basis for the understanding of tectonic processes of eastern China.Specifically,two essential issues in the study of lithospheric structure are the thermal and compositional structures,which are usually derived from either geophysical or geochemical observations.However,inversions from single geophysical or geochemical datasets have certain limitations,making it necessary to develop joint inversions of geophysical,geochemical and petrological datasets.In this paper,through thermodynamic simulation and probabilistic inversion,we inverted multiple datasets including topography,geoid height,surface heat flow and surface wave dispersion curves for the 3D lithospheric thermal and compositional structure of South China.The results reveal a thin(<100 km)and flat LAB beneath the South China Fold System Block and the lower Yangtze Craton.Also,we found that the lithospheric mantle is primarily composed of saturated peridotite,indicating that the ancient refractory lithospheric mantle has been replaced by new materials.The dominant dynamic mechanism for lithospheric thinning in eastern South China may be the flat subduction of ancient Pacific slab,while thermal erosion may have also played a significant role.In contrast,the LAB depth beneath the Sichuan Basin is much thicker(>200 km),suggesting that the thick and cold craton lithospheric roots are retained.There may exist a discontinuous interface beneath the Sichuan Basin,with the saturated lower layer thicker than the refractory upper layer.As a result,the lithospheric mantle of the Sichuan Basin and surrounding regions is mainly composed of saturated and transitional peridotite. 相似文献
8.
为更好地发挥地球化学数据及方法在异常分析及震情跟踪研判中的作用,提高地球化学数据获取的便利性及数据存储的可靠性,规范异常核实及流动观测等地球化学样品的采集及检测流程,实现地球化学数据的自动分析及相关图件的自动绘制,中国地震台网中心建立了基于Linux系统的地球化学数据库管理平台,该平台应用数据库、地理信息系统(GIS)、WebGIS等技术,集成了样品送检、实验室检测、报告产出、数据存储筛选下载分析、图件绘制等功能,利用Piper图、Na-K-Mg三角图、同位素分析等方法,分析不同样品的地球化学特征,并给出相关图件。平台自推广以来,收集了大量的地球化学数据,提升了数据的可利用性,降低了地球化学数据分析的技术门槛,在异常性质分析及震情跟踪研判中发挥了作用。 相似文献
9.
Ultrasonic elastic characteristics of five kinds of metamorphic deformed coals under room temperature and pressure conditions 总被引：3，自引：0，他引：3
The calibration of the elastic characteristics of deformed coals is essential for seismic inversion of such units, because the prediction of coal deformation is essential for both mining safety and methane production. Therefore, many samples of broken and mylonitic deformed coal were tested with ultrasonic waves in the laboratory. These samples came from four mining areas: the Huainan, Pingdingshan, Hebi and Jiaozuo coal mines, which present five different metamorphic ranks shown as cylinders striking across circular limits of steel. Under normal pressures and temperatures, ultrasonic P- and S-wave tests show that the velocities, quality factors, and elastic moduli of the deformed coals were greatly reduced compared with undeformed coals. Also, some correlation was found between the P- and S-wave velocities in the deformed coals. However, there is no evidence of linear correlations between velocity and density, velocity and quality factor, or the quality factors of P- and S-waves. Compared with the elastic characteristics of undeformed coals, such as P- and S-wave velocity ratios or Poisson’s ratio, those of deformed coals generally decrease and the P-wave quality factors are less than those of S-waves. Moreover, the analysis of the relationship between pore structure and elastic modulus shows a better correlation between the P- and S-wave velocities and effective porosity, pore volume and specific surface area. Also, there are similar relationships between the pore structure and the Young’s and shear moduli. However, there are no such correlations with other moduli. Correlations between these elastic moduli, pore structure, coal rank and density were not found for the various samples of deformed coals, which is consistent with only structural destruction occurring in the deformed coals with other physical properties remaining unchanged. The experimental results show that it is possible to predict the deformation of coals with multi-component seismic elastic inversion. 相似文献
10.
莫霍面是地壳和上地幔的边界,但莫霍面并不是一个简单的"面",而是一个反映地壳和地幔物质交换、相互作用等动力学意义的"过渡带".本文综合深地震反射、宽角地震折射和高温高压岩石物理实验结果,确定壳-幔过渡带的地震P波速度变化范围为6.8~7.5 km·s-1.在克拉通等构造活动稳定地区壳-幔过渡带内的速度梯度强且壳-幔过渡带厚度薄,而在造山带等构造活动区域壳-幔过渡带内的速度梯度弱且壳-幔过渡带厚.中国东部地区的壳-幔过渡带的平均厚度约为5~10 km,在四川盆地下方最薄（<5 km）,而在华北克拉通中部造山带下方的壳-幔过渡带最厚（~30 km）.综合地球化学结果,华北中部巨厚壳-幔过渡带主要是幔源岩浆的底侵作用和堆晶作用而形成. 相似文献
11.
HU Kai ZHAI Jianping LIU Yingjun WANG Henian ZHANG Jingrong JIA Rongfen 《中国科学D辑(英文版)》2000,43(5):507-520
The organic matter of three different chronological major carbonaceous rock gold-bearing formations of South China (Middle
Proterozoic Shangqiaoshan group of northeastern Jiangxi, Lower Cambrian Shuikou group of northern Guangxi and Devonian Shetianqiao
group of eastern Hunan) and related carbonaceous stratabound gold deposits such as Jinshan, Longshui and Shixia deposits,
respectively, has been characterized by organic geochemical techniques. These organic geochemical results show that the average
total organic carbon (TOC) content of the three chronological carbonaceous rock gold-bearing formations of South China ranges
from 0.15% to 1.56%. The thermal maturity of the organic matter of host rocks in the three gold-bearing formations is high.
The micro-component of the organic matter of the host rocks consists primarily of solid bitumen and graphite. The organic
carbon and gold of the host rocks appear to syndepositin situ during the formation of the gold-bearing formations. The organic carbon played a certain role in controlling the geochemical
environment of the gold-bearing formations. The metallogenetic mechanism of the carbonaceous rock stratabound gold deposits
of South China is closely associated in genesis with the sedimentation, diagenesis and thermal evolution history of the organic
matter of host rocks in the gold-bearing formations. 相似文献
12.
Geochemical simulation of the formation of brine and salt minerals based on Pitzer model in Caka Salt Lake 总被引：1，自引：0，他引：1
LIU Xingqi CAI Keqin & YU Shengsong . Nanjing Institute of Geography Limnology Chinese Academy of Sciences Nanjing China . China University of Geosciences Beijing China . Institute of Salt Lakes Chinese Academy of Sciences Xining China 《中国科学D辑(英文版)》2004,47(8):720-726
Copyright by Science in China Press 2004 Interactions between ions in natural waters have a great effect on the rates of redox processes[1], mineral solubility[2] and biochemical availability[3,4]. A model describing the variation of activity coefficients with ionic strength, temperature and composition of the solution is required to quantify those effects,thereby it can be used to make many geochemical calculations such as the aqueous speciation of elements, the min-eral sequence, mixing of … 相似文献
13.
This paper presents new zircon U–Pb geochronological, Hf isotopic and whole-rock geochemical data for the granitic plutons in the Xing'an Massif, Northeast China, to constrain the Late Mesozoic tectonic evolution of the Mongol-Okhotsk Ocean and the Paleo-Pacific Ocean. The zircon U–Pb ages indicate that the granitoids emplaced during the Late Jurassic–Early Cretaceous. The granodiorites show an adakitic affinity with high Sr/Y ratios and low Yb (< 1.30 μg/g) contents. The monzogranites exhibit high SiO2, low MgO contents, enrichment in LILEs (Rb, K, and Th), and depletion in HSFEs (Ta, Nb, Zr, P, and Ti). Petrological and geochemical features of these monzogranites suggest that they are highly fractionated I-type granitoids. In addition, the zircon εHf(t) values and two-stage model ages (TDM2 ) are in the range of +2.6 to +8.1 and 669–1011 Ma, respectively, indicating that primary magma was generated by partial melting of juvenile lower-crustal materials, and there was a significant crustal growth in the Phanerozoic in the Northeast China. Combined with the coeval granitoids widely exposed in the Xing'an Massif, we conclude that the Late Jurassic magma in Northeast China was generated in an extensional setting related to the closure of the Mongol-Okhotsk Ocean, but the Early Cretaceous magma was related to the subduction of the Paleo-Pacific Plate. 相似文献
14.
Xiong Xiaolin Liu Xingcheng Li Li Wang Jintuan Chen Wei Ruan Mengfei Xu Ting Sun Zhongxing Huang Fangfang Li Jianping Zhang Lei 《中国科学:地球科学(英文版)》2020,63(12):1938-1951
Science China Earth Sciences - The partitioning behavior of trace elements is of key importance for understanding the geochemical process and material cycle mechanism in subduction zones. This... 相似文献
15.
Triassic magmatism and its relation to decratonization in the eastern North China Craton 总被引：5，自引：0，他引：5
Lithospheric removal and destruction of the North China Craton have been hotly discussed recently. It has been confirmed that the timing of a strong lithospheric removal took place in Late Mesozoic; however, little is known about when the lithospheric removal was initiated and how the Late Permian to Early Triassic deep subduction of Yangtze continental crust affected the cratonic destruction. This paper presents an overview on the temporal and spatial framework and geochemical characteristics of the Triass... 相似文献
16.
中国东部大陆上地幔的基本状况 总被引：2，自引：0，他引：2
本文概述了近年来我国在地幔岩石学和地球化学研究中取得的主要结果。重点讨论了地幔流体在地幔过程中的重要作用，特别是地幔流体成矿作用，我国东部陆下地幔化学的区域性特征及其动力学意义。 相似文献
17.
Traditional methods for studying surface water and groundwater interactions have usually been limited to point measurements, such as geochemical sampling and seepage measurement. A new methodology is presented for quantifying groundwater discharge to a river, by using river surface temperature data obtained from airborne thermal infrared remote sensing technology. The Hot Spot Analysis toolkit in ArcGIS was used to calculate the percentage of groundwater discharge to a river relative to the total flow of the river. This methodology was evaluated in the midstream of the Heihe River in the arid and semiarid northwest China. The results show that the percentage of groundwater discharge relative to the total streamflow was as high as 28%, which is in good agreement with the results from previous geochemical studies. The data analysis methodology used in this study is based on the assumption that the river water is fully mixed except in the areas of extremely low flow velocity, which could lead to underestimation of the amount of groundwater discharge. Despite this limitation, this remote sensing‐based approach provides an efficient means of quantifying the surface water and groundwater interactions on a regional scale. 相似文献
18.
19.
Pankaj Kumar 《Water Resources》2012,39(5):601-609
In order to delineate geochemical processes and its relation with groundwater quality evolution, hydrochemical and isotopic analysis were carried out in coastal groundwater of Saijo plain, western Japan. From analytical results, even within a small distance from the coast; ionic concentration of water samples varies a lot which infers non-homogenous and patchy distribution of different aquifer system (complex geology). From stable isotopic results, it was found that most of sample points plotted near the local meteoric water line (LMWL) i.e. origin of ground water is meteoric in principle; however point away from the LMWL might favors exchange with rock minerals. 相似文献
20.
LIN GuangChun LI XianHua & LI WuXian Key Laboratory of Isotope Geochronology Geochemistry Guangzhou Institute of Geochemistry Chinese Academy of Sciences Guangzhou China Graduate University of the Chinese Academy of Sciences Beijing China 《中国科学D辑(英文版)》2007,50(1):1-16
Neoproterozoic magmatic rocks are widespread in the western margin of the Yangtze block, and their origin and genesis have significant implications for understanding the evolution of the Rodinia super- continent. However, there are currently two opposing interpretations for their petrogenesis and tectonic setting: mantle plume-related and island arc origin. To further verify these two competing models, SHRIMP U-Pb zircon age determinations and geochemical and Nd-Hf isotopic analyses are conducted on the mafic dykes in the Kangdian Rift, western Sichuan. U-Pb dating suggests that these mafic dykes were emplaced at 780―760 Ma, spatially and temporally coeval with the Kangding granitoid complex. The parental magmas of these dykes were derived from a depleted asthenosphere mantle source likely triggered by an anomalously-hot mantle plume. Despite some arc-geochemical features caused by variable degrees of contamination of young island arc crust during magma ascending and emplace- ment, they show general geochemical and Nd-Hf isotopic features similar to those of the intraplate basalts. Our results support the reconstruction model of Rodinia in which the South China block was located between Australia and Laurentia. 相似文献