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    2016, Volume 23 Issue 3
    15 May 2016
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    Research on formation model and geological evaluation method of the middle to high coal rank coalbed methane enrichment and high production area
    2016, 23(3): 1-9. 
    DOI: 10.13745/j.esf.2016.03.001

    Abstract ( 2457 )   PDF (1651KB) ( 6232 )  

    Enrichment mechanism and geological evaluation method of coalbed methane (CBM) enrichment and high production areas is crucial for CBM successful exploration. Previous studies have mostly focused on the formation and forecast of CBM resource enrichment areas. However,CBM production practice in a few decades shows that the source enrichment area is not necessarily a high production area. Therefore, a facing challenge in CBM exploration is how to confirm a CBM high production zone in a resource enrichment area. In this paper, considering the geological characteristics of the middle to high rank coal bearing basins in China, three different middle to high coal rank CBM production fields including the south of Qinshui Basin, the east of Ordos Basin and Lianghuai coal mines were chosen as the study fields. Combining the analysis of geological factors statistics, and the experimental and production data, the results indicate that the coupling of gas content and permeability of coal reservoir determine the formation of enrichment and high production area. Three formation models of CBM enrichment and high production area were proposed. Geological evaluation indicator including seven geological parameters of CBM enrichment and high production area were established by analytic hierarchy process and principal component analysis. CBM production capacity based evaluation method for CBM enrichment and high production area was developed. The above understandings will play an important guiding role in optimizing beneficial CBM exploration target.

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    Progress in geological researches on the deep coalbed methane reservoirs
    LI Song,TANG Dazhen,XU Hao,TAO Shu
    2016, 23(3): 10-16. 
    DOI: 10.13745/j.esf.2016.03.002

    Abstract ( 2506 )   PDF (973KB) ( 6304 )  

    The potential of deep coalbed methane (CBM) resource is huge, which makes it a new field in the unconventional natural gas exploration and development. The U.S. and Canada have successfully achieved the commercial development of deep CBM in some area, while exploration and development of deep CBM in China are still limited due to technological limitations. Based on the study of representative publications in recent years, this paper wholly summarized the progress in researches on physical properties of deep CBM reservoirs from the following four aspects: pore and fracture structures, adsorption and desorption characteristics, diffusion and seepage processes of gas in coal reservoir, and the transformability of coal reservoir. Since deep coal reservoirs are located in complex geological environments with high temperature, high pressure and high stress; thus, the permeability evolution of coal reservoir, the equilibrium relationship among CBM adsorption, desorption, diffusion and seepage, as well as the stress and strain behavior of coal tend to be more complex. Therefore, the studies of the evolution mechanism of deep coal reservoir properties under special geological conditions have theoretical and practical significance for the exploration and development of deep CBM in China.

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    The stress characteristics of the DaningJixian Area and its influence on the permeability of the coal reservoir.
    JIANG Bo,WANG Jilin,QU Zhenghui,LI Changgui,WANG Linlin,LI Ming,LIU Jiegang
    2016, 23(3): 17-23. 
    DOI: 10.13745/j.esf.2016.03.003

    Abstract ( 2391 )   PDF (1304KB) ( 6238 )  

    The DaningJixian Area is one of the key areas of coalbed methane exploitation in China. The modern stress principally controls the coal reservoir permeability. This paper explored a stress evaluation method and technique process fitted for coal reservoir, based on the analysis and calculation of well log for coalbed methane exploitation. The study has revealed that the maximum and minimum horizontal principal stress of the 5# coal seam has a general waving variation trend of lowhighlowhigh from the east to the west of the DaningJixian Area; The vertical principal stress has a general variation trend of low in East and high in West, but the increasing trend decreases in the middle area with complex geological structures. The 5# coal seam is generally under the stress transition depth, and is significantly affected by the vertical principal stress, which is in favour of the stretch of coal seam fracture and the increase of permeability, as in a tension stress environment. The orientation of the maximum horizontal principal stress is close to the development direction of the dominant fracture, which benefits the stretch of the fracture and results in the improvement of the coal seam permeability. There is a higher permeability in the areas of low minimum principal stress and of high principal stress difference.

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    Geological controls of free natural gas reservoirs in coal measures and overlying strata in the Central and Southern Qinshui Basin.
    QIN Yong, WEI Chongtao, ZHANG Zheng, et al.
    2016, 23(3): 24-35. 
    DOI: 10.13745/j.esf.2016.03.004

    Abstract ( 2355 )   PDF (2172KB) ( 6218 )  

    Paragenesis, coexploration and comining of the natural gas in coal measures and its overlying strata is an important way for making the full use of natural gas resources and for improving the economic benefit of coal measures gas (CMG) development. In the central and southern Qinshui Basin, the continuouslydeposited Upper Carboniferous to Triassic strata constitute favorable hydrocarbon sourcereservoircaprock assemblage, the thermal evolution degree of the coal organic matters is high, the hydrocarbon generation and expulsion are intense, and CMG shows are very strong, which provides the abundant gas source and reservoiring prospects for CMG accumulation. Tectonic heat event during the middle Yanshan Movement led to the two strong secondary hydrocarbon generation and expulsion from the PermoCarboniferous coal seams, providing a rich gas source for the shale and tight sandstone reservoirs in the coal measures and overlying strata. Natural gas in coal seams is expelled by the diffusion, caprocks breakthrough and seepage, and the zones with the maximum cumulative hydrocarbon expelling intensity occur along the compound syncline axis. Active and moderately active zones of the hydrocarbon expulsion are distributed in middle and northern composite syncline axis, where the level of the natural gas emission is relatively low and is favorable for free gas accumulation. Overall, in the study area, the free gas system develops with the bottom source (coal measures of the Taiyuan and Shanxi formations), the bottom to middle reservoir (Taiyuan to Lower Shihezi formations), and the upper cap(the Upper Permian to Triassic), the various kinds of the traps such as the structural, lithologic and water power ones occur, and the free gas accumulation is controlled by two critical geological periods, including the structural differentiation and abnormal thermal event during the middle Yanshan Movement and the continuous basin return since the Cenozoic.

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    Resources characteristics and separated reservoirs drainage of unconventional gas in coal measures.
    FU Xuehai, Deleqiati JIANATAYI, ZHU Yanming
    2016, 23(3): 36-40. 
    DOI: 10.13745/j.esf.2016.03.005

    Abstract ( 2349 )   PDF (833KB) ( 6162 )  

    Coal measures area group of multiply superposed reservoirs which contain coalbed methane, shale gas and tight sandstone gas(there is also a gas hydrate reservoir lying on the Jurassic coal seam in the Muli coalfield, Qinghai Province); the transitional coal measures mainly contain coalbed methane and shale gas;the inland coal measures feature coalbed methane and tight sandstone gas; the mixed reservoir containing coalbed methane and shale gas often appears in coal measures owing to the coalmudsand structure system. In China, coalbed methane resources are about 36.8×1012 m3; shale gas and tight gas resources are about 32×1012 m3 and 20×1012 m3 respectively in coal measure(not including the Northeast China). The economic benefit of developing three kinds of gas individually is not obvious; but it has some convenient conditions, such as stress relief with three kinds of gas drainage by vertical surface wells and by crossmeasures boreholes in underground mine. Technology of separated reservoirs drainage was designed by adding hanging case and communicating tubes.

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    Trace element characteristics of the Lower Cambrian black shales in middle and lower Yangtze area, China.
    YAN Deyu,HUANG Wenhui,WANG Tinghao,LIU Bei
    2016, 23(3): 42-50. 
    DOI: 10.13745/j.esf.2016.03.006

    Abstract ( 2558 )   PDF (1316KB) ( 6287 )  

    Lower Cambrian black shales deposited widely in South China,which are mainly composed of the black shales, black dolomitic shales, black arenaceous shales and black siliceous shales. There are thick mineral deposits of phosphorus, vanadium deposit, molybdenum and nickel in the black shales. Petrologic characteristics and elemental geochemical characteristics of black shales were studied systematically, and the causes of enrichment of trace elements were analyzed in detail. The results show that the black shales were formed in reductive environment of gentle slope in shallow to bathyal milieu. The layered element enrichment belts were of sedimentary origin, and abundant substances were mainly from oceanic hydrothermal fluid. In general, the contents of Co, Be, Mn and Ga are relatively low. Cu, V, Ni and Mo have high content, and most of them are higher than North American Shale Composite (NASC). Element layers of Ni and Mo are usually located above the phosphorites and the sulfide and sulfate minerals in black shales and black dolomitic shales are the main carriers. The content of TOC is as high as 12.2%, which is much higher than any other element layers. With the increase of siliceous component in shales, the contents of Ni, Mo, Fe and Co decrease significantly. Many elements, such as V, mainly occur in hydromicas in the black siliceous shales. The content of V has a positive relationship with the content of siliceous components in shale. REE in black shales varies from 76.22×10-6 to 290.67×10-6 and LREE/HREE changes in the range of 1.21 to 4.22, which indicate that light rare earth element has high enrichment. The value of Sr/Ba ranges from 0.04 to 0.34, δEu is positively anomalous and the distribution patterns of REE normalized by North American shales are gentle leaning to LREE. These evidences indicate the existence of oceanic hydrothermal fluid during the deposition process.

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    Geochemistry of the rare earth elements of coals from the Longtan Formation in Chongqing and its geological implication
    GUO Jiangfeng,YAO Duoxi,CHEN Jian,CHEN Ping
    2016, 23(3): 51-58. 
    DOI: 10.13745/j.esf.2016.03.007

    Abstract ( 2420 )   PDF (1098KB) ( 6280 )  

    The geochemical features of the rare earth elements of coals from the Longtan Formation in Chongqing were studied using the methods of inductively coupled plasma mass spectrometry (ICPMS), Xray fluorescence (XRF), powder Xray diffraction (XRD). The results show that REE distribution patterns of coal samples are similar with each other. The left curve is at a high degree and the right is low and the curve is like the shape of ‘V’ as a whole. The curve of light REEs is steep and heavy REEs is rather flat in the mass. The coalforming swamps were impacted by terrigenous detrital deeply. There is high content of REEs in No.5 coal seam of Nantong Coal Mine,which is approximate twice of the average value of Chinese coal. It was controlled by Hannan Oldland, Dabashan Oldland and Longmenshan Island, only a little terrigenous detrital material was from Kangdian Oldland. There is low content of REEs in No.6 coal seam of Donglin Coal Mine,which is below the average value of Chinese coal. The effect of marine water was obvious. Although the REE contents of coal samples were not impacted by alkaline tonstein, the floor of No.6 coal seam of Donglin Coal Mine was impacted by it strongly. Based on the analysis of rare earth elements content and its ratios of coal seams, the depositional environments of Longtan Formation in the research region are sea bay (or lagoon) to tidal flat and shallow sea carbonate platform.

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    Geochemistry characteristics of sulfur and its effect on hazardous elements in the Late Paleozoic coal from the Qinshui Basin
    LIU Bei,HUANG Wenhui,AO Weihua,YAN Deyu,XU Qilu,TENG Juan
    2016, 23(3): 59-67. 
    DOI: 10.13745/j.esf.2016.03.008

    Abstract ( 2422 )   PDF (1414KB) ( 6130 )  

    Sulfur in coal is the main carrier of many hazardous trace elements. Based on sulfur form analysis, inductively coupled plasmamass spectrometry and Xray diffraction, the distribution of sulfur and hazardous trace elements in coal from the Qinshui Basin were analyzed and the influence of sulfur on hazardous trace elements was discussed. The occurrence modes of sulfide in coal were identified under microscope and scanning electron microscope with Xray energy dispersive spectrometer (EDX). The results show that organic sulfur is the main type of sulfur in coal, accounting for 78% of total sulfur. Pyritic sulfur only dominates in some highsulfur coals of the Taiyuan Formation. The microscopic occurrence modes of pyrite mainly include framboidal pyrite, thinlayer pyrite, euhedral crystals, nodular pyrite, massive pyrite and finegrained pyrite accumulations, and the occurrence modes of marcasite mainly include polysynthetic marcasite, plate marcasite and spearhead marcasite, some of which coexist with pyrite. Hazardous trace elements in coal from the Qinshui Basin are low and will not affect the environment during coal mining and coalbed methane development. Pyrite is the main carrier of As, Se and Hg, while organic sulfur determines the content of U in coal. It is suggested that the influence of seawater during and after peat swamp stage is the key reason for high total sulfur and pyritic sulfur in coal of the Taiyuan Formation. Sulfur in coal of the Taiyuan Formation has diverse sources and pyrite in coal of the Taiyuan Formation is characterized by multistage evolution.

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    A review of the geochemistry of tin (Sn) in Chinese coals: Measurement, concentration, distribution and modes of occurrence
    QU Qinyuan,LIU Guijian,SUN Mei,QI Cuicui,LIU Yuan
    2016, 23(3): 68-73. 
    DOI: 10.13745/j.esf.2016.03.009

    Abstract ( 2562 )   PDF (881KB) ( 6034 )  

    Tin (Sn) is an element with negative environmental effects. In recently years, samples collected from sediment from many places showed very rapid increasing ratio which suggests that Sn emitted from coal might be an important source. In this study, we try to make an overview on the progress of studying of Sn in Chinese coals. Generally, Sn in Chinese coals was 23 μg/g, relatively higher than the world average and the earth crust abundance. As the content of Sn in Chinese coal ranges from 0.4 to 10.5 μg/g, it is suitable to use the ICPMS or high sensitivity AAS as the measuring instruments after digestion with microwave oven. With the low content, Sn in coals hardly exists in the term of independent minerals. However, several kinds of possible modes of occurrence of Sn were proposed here, including cassiterite, sulfide tin compounds, Snincluded niobiumtantalum minerals, organically bonded Sn, Snincluded silicates and loosely bonded ionic Sn. Based on the occurrences of Sn, the genetic factor of some coal seams which were enriched in Sn was discussed here. Moreover, the mobile ionic Sn and organically bounded Sn should be paid much attention because of their high possibility of emitting into the environment.

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    Geochemistry of trace elements in the No.5 Coal from the Chuancaogedan Mine, Junger Coalfield
    YANG Ning,TANG Shuheng,ZHANG Songhang,CHEN Yunyun
    2016, 23(3): 74-82. 
    DOI: 10.13745/j.esf.2016.03.010

    Abstract ( 2386 )   PDF (1345KB) ( 6050 )  

    In order to ascertain the geochemical features of trace elements in the No.5 coal seam at Junger Coalfields Chuancaogedan Coal mine, the mineral composition characteristics were observed through optical microscope, SEM and the Xray Diffraction (XRD) method, the contents of trace elements in coal were determined by Inductively Coupled Plasma Mass Spectrometry (ICPMS), and the occurrence of trace elements were then analyzed based on statistics. The results show that the contents of Li, Be, F, U, Hg in the No.5 coal seam is higher than that in the No.6 coal and Chinese coal. Li, F, Ga, Se are strong inorganic affinity elements, Be, As, U are organic affinity elements, and Hg is of significant positive correlation with sulfur content. Organic combination, inorganic compounds and sulfide bonded forms are the dominant occurrences of these trace elements in the No.5 coal.

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    Geochemistry of trace elements in the Mengtuo Neogene lignite of Lincang, western Yunnan
    CHEN Jian,CHEN Ping,YAO Duoxi,GUO Jiangfeng
    2016, 23(3): 83-89. 
    DOI: 10.13745/j.esf.2016.03.011

    Abstract ( 2359 )   PDF (876KB) ( 6086 )  

    To investigate the geochemical characteristics of trace elements in the Mengtuo Neogene lignite of Lincang in western Yunnan, a total of 11 lignite samples were collected, and the trace elements were determined by ICPMS and ICPCCTMS(As and Se). Results indicated that the enriched trace elements were different from the Dazhai Gerich coals, i.e., significant enrichment of Rb(96.1 mg/kg), Sb(15.3 mg/kg) and Cs(25.9 mg/kg), enrichment of W(10.6 mg/kg) and U(20.2 mg/kg), and slight enrichment of Be(7.84 mg/kg), Ga(16.1 mg/kg), As(11.6 mg/kg), Cd(0.67 mg/kg), Sn(6.66 mg/kg), Pb(34.6 mg/kg), Bi(3.86 mg/kg) and Th(28.2 mg/kg) when compared to common Chinese coals, which might be inherited from the weathered granite around coalaccumulating basin. The REY concentrations in Mengtuo lignite range from 121 mg/kg to 420 mg/kg, with an average of 251 mg/kg, higher than that of Chinese coals. The UCCnormalized REY distribution patterns of Mengtuo lignite are characterized by the significant positive Ce anomaly and negative Eu anomaly, obviously differentiating from that of Dazhai coals, suggesting a terrigenous input of REY from weathered granite.

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    Study on the geochemistry of rare earth elements in the Permian coal from Xiayukou, Weibei Coalfield
    CUI Xiaonan,HUANG Wenhui,AO Weihua,ZHOU Hongpu,LIANG Fei
    2016, 23(3): 90-96. 
    DOI: 10.13745/j.esf.2016.03.012

    Abstract ( 2255 )   PDF (1135KB) ( 6106 )  

    The REY(REE+Y) content in the Permian coal seams mined at Xiayukou of Weibei were investigated by inductively coupled plasma mass spectrometry. The content characteristics and distribution patterns of REY were analyzed. Furthermore, the origin and occurrence states of REY were discussed. The results are as follows: compared with mean value of coal in China and North China, the REY are not obviously enriched in this research area with an average of 87.70 μg/g; the mean content of REY in No.2 coal is higher than that of No.3 coal due to the different coalforming microenvironment between them; the ∑REY reduced from top to bottom in the No.3 coal seam and enriched in the floor and roof samples; the light REY is obviously enriched compared with the heavy REY. The weak positive anomaly value of Ce indicates that seawater had little influence on the coal swamps. The negative anomaly value of Eu and the negative correlation between ∑REY and CaO indicate the sediment environments were acidreducing environment. The REY distribution patterns in coal, roof and floor seam samples are similar, indicating that they had the same and stable material supply during the coal formation. Positive but insignificant correlation (R=0.216) of ∑REY vs. ash yields demonstrates the possible coexistence of inorganic and organic states of REY in coals.

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    Technology process and application prospect of underground coal gasification
    LIU Shuqin,ZHANG Shangjun,NIU Maofei,YU Li
    2016, 23(3): 97-102. 
    DOI: 10.13745/j.esf.2016.03.013

    Abstract ( 2407 )   PDF (1422KB) ( 6134 )  

    Underground coal gasification(UCG) is a method of in situ coal mining. In this paper, the technology process, reaction characteristics, influencing factors, together with the development and application prospect of UCG were introduced. In addition, site selection and groundwater pollution prevention regarding UCG were especially emphasized. Gas production during UCG is based on the reactions of the mixture of coal and rocks in the percolation channel, and involves the chemical reactions along both the axial direction and radial direction. With the expanding of gasification face, the period of gas emission on stable process control is formed. The UCG technology of retraction gasification by moving injection using coiled tubing along long distance directional drilling borehole provides the technical basis for UCG commercialization. UCG gas could not only be used for IGCC, but also be used as chemical raw gas for synthesis of methanol, ethylene, oil, aromatic hydrocarbons, etc. UCG must have broad application prospect with the remarkable safe and environmental advantages if groundwater pollution is properly carried out.

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    Altered volcanic ashes in coalbearing strata: Advances in mineralogy and geochemistry
    ZHAO Lei,DAI Shifeng,WANG Xibo
    2016, 23(3): 103-112. 
    DOI: 10.13745/j.esf.2016.03.014

    Abstract ( 4792 )   PDF (1116KB) ( 6031 )  

    Tonsteins, and less commonly bentonites and Kbentonites, are known to occur in many different coalbearing formations in the world throughout geological time, although the actual definition of tonsteins is still regarded in some cases as controversial.Leaching of the precursor volcanic ash by ground waters and organic acids in the peatforming environment would be expected to result in enrichment of some elements that were released from the ash and accumulated as minerals or organometallic compounds in the immediately adjacent coal. The occurrence of such minerals may therefore be indicative of volcanic influence during peat accumulation and coal formation. Tonsteins are thought to provide geochronological markers, with a widespread distribution that enables stratigraphic correlation. The primary minerals in tonsteins, if preserved, may also provide opportunities for absolute age determination. Some alkaline tonsteins are indicators for the discovering of rare metal ore deposits. The geochemical characteristics of tonsteins serve as indicators of magma affinities and volcanotectonic settings.

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    Progress of research on mineralization mode of large coalGe deposits in China: CoalGe deposit in Wulantuga of Inner Mongolia and Lincang of Yunan
    WANG Tinghao,HUANG Wenhui,YAN Deyu,TANG Xiuyi
    2016, 23(3): 113-123. 
    DOI: 10.13745/j.esf.2016.03.015

    Abstract ( 2451 )   PDF (1523KB) ( 6124 )  

    Germanium is the most researched and bestdeveloped available associated element in coal. All of coal in the nature has Ge, while a tiny minority can accumulate commercially and most has little Ge. The average mass fractions of Ge in coal in China, USA, Australia, UK and former Soviet Union are 3.6×10-6, 5.7×10-6, 2.9×10-6, 4.4×10-6, and 1.5×10-6, respectively. n×100×10-6 is high anomaly in Ge content. Two commerciallyexploited coalGe deposits have been found in China, namely, Cenozoic basin in western Yunnan Province and Mesozoic basin in Inner Mongolia Autonomous Region. But the geological factors of two basins are different. In the article, we mainly compare two basins unique features respectively.The situation of Ge in coal in Yunnan Province is abundant and in the stage of mature development. The known reserve is high to 800 tons in Bangmai Basin in Lincang County, which belongs to extralarge Ge deposit. The approximate area is 16.4 km2 of Bangmai Basin, which is a smallscale Neogene faulted basin. The Ge distributions in each coal seams are not extremely even. Ge in coal generally occurs at the bottom of coal seams in the formation and at the margins of basins in planar surface. The basement of these Neozoic basins in western Yunnan Province can supply granite which is rich in Ge. The average Ge value in binary granite distributed in western Bangmai Basin is 3.5×10-6, and biotite granite in the east is 1.7×10-6, which uneven distribution is related with the different Ge sources supplied by two types of granite. Ge, which was released from source rocks, went into the solution, and flowed into coalbearing basins through favourable palaeohydrologic geological conditions.The coalGe deposit in Shenli coalfield in Inner Mongolia is in the stage of development. Monzonitic granite and diorite outcrop in western mineral land have high Ge value above 15×10-6 after sampling and testing. A bulk of active germanium was released from these rocks by oxygenolysis and decomposition, dissolved in the form of germanium acid solution and migrated into coal basins.Ge abundance increases in upper coal seams because Ge dissolved in hydrothermal fluid in thermometamorphic process and migrated upward. And it decreases near surface because of subsurface water leaching and migration downward. The result generated by the two migrations is that the Ge enriched zone formed between lower bituminous coal and low metamorphic coal near surface (volatile separated rate is above 37%), in which the average Ge value is 15×10-6 and the maximum value is high to 450×10-6.The Ge enrichment and geological factors in Shengli and Yimin coal fields, Inner Mongolia have great difference with those in Lincang County, Yunnan Province. It may be found new mineral occurrences in further general investigation and exploration in Erlian Basin Group which has semigraben basin, graben basin, faulteddepressed basin and contains affluent coal, oil and natural gas. The geological research outcomes related with coal and petroleum are abundant, which is a perfect basis for advanced research on coalGe deposits in basin groups.

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    The human health risk and safety threshold of arsenic in soils of a coal chemical industry area in Northwest China
    JIA Jianli,LI Xiaojun,YANG Le,HU Lei
    2016, 23(3): 124-132. 
    DOI: 10.13745/j.esf.2016.03.016

    Abstract ( 2275 )   PDF (1363KB) ( 6146 )  

    In this study, soil samples were collected from a largescale coal chemical industry area in Northwest China. And then arsenic (As) in soil samples was detected by novel collision/reaction cell technology (CCT) of inductively coupled plasma mass spectrometry (ICPMS, collectively ICPCCTMS) after closed vessel microwave digestion. Human health risks of As for three different gasification units were evaluated in three major exposure pathways, including inhalation particles, skin contact and ingestion of soil particles. Results showed that the comprehensive carcinogenic risk of As in coal chemical industry area soils is 6.159.24 times the acceptable risk level, and the hazard quotient of different coal chemical industry area is acceptable. The main exposure route of As in coal chemical industry area soils is ingestion of soil particles, which can account for 68.64% of total carcinogenic risk. Considering different control values by each exposure pathway, the minimum control value (1.59 mg/kg) in the pathway of ingestion of soil particles, which also have a maximum contribution to the carcinogenic risk could be selected as the strict reference of safety threshold for As in soil environment in coal chemical industry area. Combining the characteristics of coal chemical industry in China, background value of As in regional soil, regional climate and geological characteristics, etc., and taking into account the difference of the acceptable level of human health risk of As in different countries and regions and feasibility, the safety threshold of As in the soil environment of certain coal chemical industry could be comprehensively determined.

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    Isotopic geochemical characteristics of groundwater and its geological significance in Sunan mining area
    GUI Herong,CHEN Song
    2016, 23(3): 133-139. 
    DOI: 10.13745/j.esf.2016.03.017

    Abstract ( 2327 )   PDF (1093KB) ( 6013 )  

    Groundwater is not only the important water resource for human production, but also affecting coal mining safety in coalmining region. In order to understand the characteristics of isotopes in groundwater, the analysis of T, D, 18O, 87Sr/86Sr, 13Cdic and 18Odic compositions of groundwater samples from loose aquifer, sandstone aquifer and limestone aquifer in Sunan mining area, Anhui Province had been performed; the result were used to discuss the evolutionary age, isotope characteristics and its influencing factors of groundwater samples based on traditional graphic methods; the results showed that the tritium contents in groundwater samples from three aquifers are low, which suggests that the groundwater in Sunan mining area are supplied by submodern water. The D and 18O concentrations are clearly affected by the surrounding rock; the values range from -44.3‰ to -68.5‰ and -8.78‰ to -6.29‰, with the average of -61.15‰ and -8.16‰, respectively. The content of carbonate in surrounding rock determined the relationship between 13CDIC and 18ODIC. The values of 87Sr/86Sr varied from 0.7106 to 0.7123, with an average value of 0.7112, which also could be used to identify the three aquifers, since the value of 87Sr/86Sr is clearly influenced by the waterrock interactions.

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    Geochemical characteristics of emergent gas and groundwater in Haiyuan fault zone
    SUN Xiaolong,WANG Guangcai,SHAO Zhigang,SI Xueyun
    2016, 23(3): 140-150. 
    DOI: 10.13745/j.esf.2016.03.018

    Abstract ( 2269 )   PDF (1814KB) ( 6285 )  

    Seven measuring areas were selected and named Caowa(CW), Caiyuan(CY), Wanjia(WJ), Shuiquan(SQ), Santang(ST), Songshan(SS) and Anyuan(AY) respectively, in which soil gas was measured and geochemical composition in groundwater was detected. Characteristics of tectonic activity in Haiyuan fault zone was analyzed according to the soil gas concentration, chemical composition and isotopic composition in different area. Analysis results show that (1) those areas with higher soil gas concentration were ST and SQ along the fault strike;along the vertical direction of the fault, the concentration of Rn in soil gas was lower in the central position of fault than both sides; helium concentration and isotopic testing results show that mantlederived gas was mixed in the soil gas in ST, SQ and CY areas; that (2) according to results of the chemical composition and hydrogen isotope in spring water, we thought that there were more interaction and higher equilibrium state between groundwater and rock, and the depth of groundwater circulation were deeper in the areas of SQ and ST, compared to other areas in Haiyuan fault zone; that (3) the result of spring tritium activity showed that the groundwater recharge area in SQ area was far away, the water cycle period is longer, and the exchange action between old and new water is slow. Above all, the central and western areas of Haiyuan fault (SQST), which is close to the rupture zone of the 8.5 earthquake in 1920, has lower fault blocking degree and deeper connectivity with deep crust. So, different from other areas, those areas in central and western of Haiyuan fault has more conducive to subsurface fluid to diffuse towards the surface.

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    Predicting the trends of pollutant concentrations in groundwater based on the combined method of the improved quantification theory and RBF artificial neural network
    YANG Ping,WANG Xinmin,LU Laijun
    2016, 23(3): 151-155. 
    DOI: 10.13745/j.esf.2016.03.019

    Abstract ( 2219 )   PDF (726KB) ( 5824 )  

    In this paper, an improved quantification theory I proposed by Chikio Hayashi was used as a preprocessing tool to covert quantitative data to qualitative data and to reduce data dimensionality for 20 factors impacting groundwater quality. Then 8 important characteristic factors were used as nodes of input layer in RBF Neural Networks, and RBF ANN model was created through training and learning the sampling data of monitoring well, finally migration and transformation law of pollutants were revealed. By using the combination model of the quantification theory and RBF ANN, the simulation results covered most of the existing experimental data and could forecast the dynamic changes of groundwater quality. The result is relatively accurate for a wide range and has some promotional value.

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    The preliminary research on the cluster feature of timespace distribution of Chinese coalmine disasters and earthquake activities
    CHEN Bo.
    2016, 23(3): 156-169. 
    DOI: 10.13745/j.esf.2016.03.020

    Abstract ( 2249 )   PDF (2781KB) ( 6387 )  

    Recently, Chinese Geographic Name Database was published, based on which the author has located as many as 5825 coalmines. “Replayed” by natural order, it has been found that 48.7% of coalmine disasters did not occur randomly, but tended to occur continuously within certain scopes, presenting cluster feature, some accompanied with earthquakes (with magnitude>3), in which all the disaster types are involved. In further research, with micro earthquakes introduced, quite a few coalmine disasters are found to be accompanied with micro earthquakes, in which earthquakes tended to occur earlier than coalmine disasters. Of all the causative factors, stress disturbance is the only one that can cause all kinds of disasters at one time. The earthquakes accompanied with disasters may be the vital geophysical evidence of the tectonic stress fluctuation around mining area(causing coalmine disasters). This paper made a quantitative research, by which the ratio of disasters involved in cluster series and the number of earthquakes accompanied with disasters are achieved. For example, under threshold of 100 miles, of all the 7368 disasters, at least 38.5% are involved in cluster series, in which 372 disasters are accompanied with earthquakes. Of all the cluster series, the proportion of the durations sorted by descending order is 2 days, 1 day, 3 days, 4 days, …, 11 days. Potentially, the duration of cluster series reflects the duration of stress disturbance. The majority of the durations are composed of short ones, such as 1 and 2 days, which correspond well earthquakes (with magnitude<5) and are speculated to be more likely related to local stress disturbance. While the minority long durations correspond well with fatal earthquakes, which are speculated to be related to regional stress disturbance. In addition, all the cluster series under every threshold have been picked out successfully and a full open access is provided. As to the mechanism, the author makes the most common speculations on a given geological model, in which five affecting cases are analyzed. The phenomena remain unknown to human, which, to earthquake research and coalmine disaster prevention, widely scientific significance is suggested.

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    Discovery of Pelmatozoan reefs of Early Tremadocian at Liujiachang in Songzi Area
    XIAO Chuantao, TIAN Yicong, XIAO Sheng
    2016, 23(3): 170-177. 
    DOI: 10.13745/j.esf.2016.03.021

    Abstract ( 2240 )   PDF (1641KB) ( 6057 )  

    It is the first time that Pelmatozoan reefs was discovered from early Tremadocian strata (lower Nanjinguan Formation) of early Ordovician at Liujiachang in Songzi area of Hubei Province. Pelmatozoan not only forms individually bafflestone reef, but also combines together with low microbial algae to form microbial reefs, namely baffling and binding reefs. Baffling reefs can be divided into Pelmatozoan bafflestone reefs and stalked echinodermsconcentric circles cyanobacteriabindingbaffling reef, Binding reefs can be divided into the siliconized spongestalked echinodermscyanobacteria bafflingbinding reef and stalked echinodermscyanobacteria binding reef. Accordingly, it can be divided into 4 biomes, namely, Pelmatozoan community, stalked echinodermsconcentric circles cyanobacteria community, siliconized spongestalked echinodermscyanobacteria community and stalked echinodermscyanobacteria community. Composition, structure, function and ecologic environment of each community are expounded and analysed. In the reefs discovered, the diameter of pelmatozoan is much smaller than that of pelmatozoan during late Tremadocian, this phenomena shows the evolution rule of organism from small to large during geological time. In the baffling reefs found, the content of pelmatozoan is lesser than that of late Tremadocian pelmatozoan, this phenomena reveals that reproductive ability and reefbuilding function of organism is weaker during early geological time. In the discussion of the relationship between filter feeding of pelmatozoan and destruction of the stromatolites lamina in the study area, this paper argues that the baffling of pelmatozoan may be the main reason blocking off part of the lamina growth of stromatolites, while filter feeding of pelmatozoan may be secondary reason, As the pelmatozoan is not a wandering animal or boring animal, the predation and disturbing ability may be poorer than that of other boring animals. The discovery of organic reefs demonstrates that the earliest reefbuilding age of stalked echinoderms in the world is early Tremadocian in the study area, at the same time, it also confirmed that early Tremadocian is also the earliest reefbuilding age during Ordovician. Therefore, the discovery of early Tremadocian Pelmatozoan reefs is not only of important significance theoretically for the evolution studying of stalked echinoderms reefs and Ordovician reef, but also of certain practical significance for the evaluation of oil and gas for Jianghan Plain and other fields of the economy.

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    The discovery of aragonite sedimentary on the top of lacustrine sedimentary in the Middle Pleistocene in Yangyuan Basin, Hebei Province and its scientific significance
    JI Yunping, WANG Guiling, ZHAO Hua
    2016, 23(3): 178-185. 
    DOI: 10.13745/j.esf.2016.03.022

    Abstract ( 2198 )   PDF (1327KB) ( 6004 )  

    Yangyuan Basin located in the Northwest of Hebei Province is a Cenozoic rift basin. It was occupied by the palaeolake Nihewan for a long time during the Quaternary and filled up by a thick succession of lacustrine and fluvial sediments. Several chemical sedimentary layers in the basin had been found previously and the chronologic results suggested that they belonged to the late Pleistocene. Recently, a new chemical sedimentary layer was found in Beiliang section located in 16 km southwest of Yangyuan County by field investigation, which widely distributed in the top of lacustrine and fluvial sediments in western basin. In order to discuss the sedimentary processes and environmental history of the palaeolake Nihewan, the sampling of this section was performed in much detail, and the samples were analyzed by OSL dating, Useries dating, SEM, XRD, XRF, and diatom and ostracoda fossil identification. Its Useries dating shows that the age of grayish white chemical sedimentary layer is about 270 ka, much older than that of the chemical sediments found before. Mineralogical data of this grayish white chemical layer reveal that it was mainly composed of aragonite(71%) and ankerite (12%). Ostracoda identification shows very low diversity (only two ostracod species) and very high abundance. These evidences suggest that the chemical sedimentary layer was formed under a relatively warmer and dryer climate. The palaeolake had shrank rapidly and became a salt lake during that stage, which led to a large number of minerals like aragonite to be precipitated. The disappearance of the palaeolake Nihewan was during the late Middle Pleistocene at Beiliang area. This result would be of a great significance for reconstruction of paleoenvirenment in northern China during the late Middle Pleistocene.

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    Palaeogeographic evolution of the Upper Cretaceous in Termit Basin and its adjacent areas, Niger
    MAO Fengjun,LIU Ruohan,LIU Bang
    2016, 23(3): 186-197. 
    DOI: 10.13745/j.esf.2016.03.023

    Abstract ( 2527 )   PDF (2313KB) ( 6040 )  

    The Termit Basin and its adjacent areas are the typical MesozoicCenozoic rift basin of West African Rift System (WARS), and they are also the most potential risk exploration area for CNPC overseas. However, because of the complex tectonic movement, the study area is lack of system analysis in paleogeographic evolution of the Upper Cretaceous. In this article, we take the Termit Basin and its adjacent areas as our study area. On the basis of tectonic evolution, we comprehensively utilize geochemistry, stratigraphy and geophysics to analyze the paleosedimentary environment and Paleogene provenance in the study area. The study suggested that during the early Cenomanian in the study area the transgression began to occur, and it achieved maximum transgression in the Santonian, then the sea level began to descend. Because of the regional tectonics, the uplifting movements occurred in the Termit Basin and the west part. The geochemical, lithological and seismic data show that the Termit Basin and its adjacent areas were in shallow shelf deposition during the CenomanianSantonian period, and the provenance mainly came from the NE direction; during the second period, the sedimentary facies of marine deposit transited to transitional facies, and the provenance came from the NE and SW directions; and all of this had provided the theoretical basis for the analysis of sedimentary systems and sand body prediction.

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    Geological features of Djanydjer ophiolitic mélange and chronology of gabbro in Kyrgyz, South Tianshan
    WANG Bin, CHEN Bo, JI Wenhua
    2016, 23(3): 198-209. 
    DOI: 10.13745/j.esf.2016.03.024

    Abstract ( 2297 )   PDF (2313KB) ( 6004 )  

    Djanydjer ophiolitic mélange in the Kyrgyzstan, South Tianshan suture are composed of serpentinized peridotite, gabbro, basalt and chert. Two groups UPb zircon ages of 422.0±2.0 Ma(MSWD=1.2) and 397.3±3.9 Ma (MSWD=0.6) have obtained for the gabbro. Considered with chronology studies of ophiolites in ChinaKyrgrz, South Tianshan, the older age (422 Ma) represents the crystallization of gabbro, which implies the oceanic basin separated the Tarim craton and Kyrgyz Middle Tianshan terrane has existed in the early stage of the Late Silurian. The younger age might be related to metamorphism during the oceanic lithosphere obduction or the postcollisional magmatism. Muscovitequartz schist in the same belt with Djanydjer ophiolitic mélange was considered as a part of Precambrian metamorphic terrane. It has similar petrology and deformation characteristics with the host rocks of Atbashi ecologite. Its detrital zircons vary widely in age from 406 Ma to 2856 Ma, which is similar to that reported from the Atbashi greywacke. Compared with the age spectrum of zircons from Tarim Craton and Atbashi greywacke, the protolith of the muscovitequartz schist has a depositional age <406 Ma and the provenance was probably in the North and Middle Tianshan.

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    The genesis of layered iron bodies occurring in the middle zone of Panzhihua intrusion, Zhujiabaobao mine: Evidence from quantitative crystal textural analysis
    LI Jie, LUO Zhaohua, YANG Zongfeng
    2016, 23(3): 210-220. 
    DOI: 10.13745/j.esf.2016.03.025

    Abstract ( 2520 )   PDF (1671KB) ( 6201 )  

    Magmatic iron deposit, occurring in Panzhihua layered intrusion, is one of the most important iron resources in China and builds up Emeishan mantle plume. However, the metallogenic mechanism is still left controversial. In this article, the middle zone of Panzhihua intrusion in Zhujiabaobao mine is investigated. With the analysis of quantitative clinopyroxene texture, the genesis of layered iron bodies has been put forward based on field and microscopic observation. In the aspect of petrography, the textures of clinopyroxene and plagioclase in dissolved samples have been obviously changed by dissolution and the dissolved parts were occupied by oxide. Crystal Size Distribution diagrams show that dissolved samples have steeper CSD slopes and are more curved at small granularity with higher oxide than those of the original. It is explained that the dissolution results in a more steep CSD slope and a coarseninglike CSD diagram. Spatial Distribution Pattern shows that crystals in the upper part are better sorted, however the lower underwent compaction from the former. Sorting in magmatic processes have been recorded in the upper part and the lower are suffered from dissolution which results in bigger pore space. Rocks with larger space can not hold up the weight from the lower part so compaction trend is shown up. It is shown that fluid exists during oxide forming processes revealed by dissolution of rockforming minerals and fluidrich amphibole together with serpentine around the dissolved minerals and interstitial oxide. During the late magmatic stage of Panzhihua intrusion. Fluid rich in iron injected into the unsolidificated body, resulting in the dissolution, then filled the pore space. Iron formed when fluid escaped. Pervasive dissolution occurred in the lower part and ironrich fluid escaped by compaction, so poor bulk ore body came into being. In the upper part, fluid moved horizontally without compaction, so rich layered iron body formed. This oreforming pattern is similar to transmagmatic fuild metallogenic model.

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    Magmatic processes in Jiaochong gold deposit, Tongling, China: Evidence from dioritic porphyrite
    DU Jingguo, DU Yangsong, CHEN Linjie
    2016, 23(3): 221-229. 
    DOI: 10.13745/j.esf.2016.03.026

    Abstract ( 2382 )   PDF (1573KB) ( 5966 )  

    This paper presents new petrographic observations and microprobe analyses for the dioritic porphyrite from the Jiaochong gold deposit. Petrographic observations indicate the existence of unique quartz, plagioclase and hornblend phenocrysts in the rock. The quartz phenocryst is composed of resorbed core and growth rim, with melt inclusions along the border between core and rim. The plagioclase phenocrysts consist of resorbed core, resorbed growth mantle, and growth rim, with melt inclusions along resorption surfaces in the mantle. Hornblende poikilotopes are observed within core and mantle of the plagioclase phenocrysts. Hornblend phenocrysts are elongated in shape and contain acicular apatite poikilotopes. Microprobe analyses show that the An content of plagioclase from core to rim presents a reduced tendency and appears some An peaks at mantle, the aluminum content of hornblende from core of plagioclase to the matrix is decreasing. Using AmpPl geothermobarometry and wholeAl content of hornblende geobarometry the crystallization temperature and pressure of plagioclase phenocryst core and hornblende inclusions within it, the mantle of plagioclase and its hornblende inclusions, and coexisting HblPl micolites in the matrix are calculated respectively. The results show that the temperatures are 806.84808.75, 791.00797.86 and 660.3683.9  ℃, respectively. The pressures are 6.757.06 kb, 4.634.87 kb, and 2.062.12 kb respectively. The corresponding formation depths are 25.5226.70, 17.5018.40, and 7.798.02 km, respectively. Besides, the crystallization conditions of hornblende phenocryst are similar to those of embedded hornblende in the mantle of plagioclase phenocryst, the pressure of crystallization and corresponding depths are 4.484.83 kb and 16.9318.25 km, respectively. On the basis of the petrographic and geochemical analytical results, the present paper proposes the model of multiple magma chambers: the deep mantlederived transmagmatic fluids activate differentlevel magma chambers, as a result, forming intermediatebasic and granodioritic magmas,and the magma mixing between them has occurred. Finally, the mixing intermediate meltfluid flow driven by fluid pressure emplace rapidly near the surface, meanwhile, large amounts of volatile (orebearing fluid) are released. The exhalation process caused by decompression is probably the main mineralization mechanism.

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    The geochemical characteristics and formation mechanism of the Eocene lacustrine dolomite reservoirs in the Western Qaidam
    HUANG Chenggang, YUAN Jianying, Tian Guangrong
    2016, 23(3): 230-242. 
    DOI: 10.13745/j.esf.2016.03.027

    Abstract ( 2381 )   PDF (2318KB) ( 6140 )  

    In recent years, important breakthrough has been made in exploring petroleum from dense carbonate reservoirs of Eocene Epoch in Western Qaidam Basin. Among the carbonate rocks in the reservoirs, dolomite proves to be the high quality reservoir rock type. By the comprehensive petrologic, textural and geochemical studies, we describe and demonstrate the origin and characteristics of the two sorts of lacustrine dolomites from western Qaidam Basin. One is the protistic algal dolomite, which is rare in this area. The analytical results of electron probe energy spectrum scan showed that the Mgenriched zone and the distribution of algal lamination are highly consistent,which, therefore,strongly indicates its microbiological characteristics because the microbial activity can overcome dynamic obstacles and create a favorable microenvironment for the formation of dolomite. Another is the penecontemporaneous metasomatic micritic dolomite, which are widely distributed in the study area. The results of the observation with polarizing microscope and Xray diffraction analysis showed that most of the dolomicrites contain detrital grains and argillaceous components, which is due to the mixed deposition of detritus that brought from the peripheral braided delta. The results of electron microprobe analyses on rock components showed that the average content of FeO is 0.942% and that of MnO is 0.052%. These data are significantly lower than those of hydrothermal dolomites. And the SiO2 and Al2O3 contents are also higher, which fully show a penecontemporaneous metasomatic origin. The discrete rare elements spider diagram shows the diversity of the source material of this mixedly deposited lacustrine dolomite. The ∑REE average value is less than that of the upper crust ∑REE(146.37×10-6), but much larger than the value of chondrite ∑REE(2.56×10-6) and without Eu negative anomaly. Carbon isotope negative offset is primarily impacted by the CO2 produced from the oxidation of reservoir organic matter and the surface water provided by the peripheral braided delta, which increased its light carbon components. The oxygen isotope positive offset is mainly impacted by the saline lacustrine basin depositional environment. Evaporation makes δ18O increase in lake water. Though the surrounding river system could bring forth some light oxygen components, it caused little success. It obviously reveals that penecontemporaneous metasomatic dolomite is opposite to the hydrothermal ones which caused the oxygen isotope positive offset. During its formation process dolomicrite generated a lot of disseminated intergranular pores, on account of intergranular diffusion process. And the pore radii are small while the number of them are numerous, which is the major cause for the forming of “medium porosityextralow permeability” type reservoir. This type of pore has a strong ability to resist compaction. It is the best oil and gas reservoirs in study area. The research results have great significance for the exploration of oil and gas in the deepseated dense carbonate rocks in Qaidam Basin.

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    The characteristics of organic matter in Maoming oil shales and their paleoclimate significance
    CAO Xinxing, SONG Zhiguang, LI Yan
    2016, 23(3): 243-252. 
    DOI: 10.13745/j.esf.2016.03.028

    Abstract ( 2307 )   PDF (1331KB) ( 6066 )  

    The late Eocene to the early Oligocene (about 33.5 Ma) climate transition determined by the marine sediment studies was a global event based on marine sediments during the Paleogene, while there is few researches on the terrestrial sediment records of this climate transition. The Youganwo Formation oil shales from Maoming basin of Guangdong Province, deposited during the late Eocene to the early Oligocene, have been studied in terms of organic matter abundance, hydrocarbon components and the carbon isotopic composition of individual hydrocarbon compounds, and aiming to study the response of terrestrial organic matter to the EoceneOligocene transition (EOT) at the low latitude region. The results show that the δ13C composition of nalkanes in the shallower buried sample display a significant positive excursion ranged from -19.1‰ and -25.9‰ with an average of -22.2‰. By contrast, the δ13C composition of nalkanes in the deeper buried sample is much negative and varied from -23.7‰ and -30.2‰ with averaged at -26.3‰. The difference between the δ13C compositions of corresponding nalkanes in these two samples vary from 1.5‰ to 8.1‰ with an average deviation of 4.6‰. This significant shift in the δ13C composition of nalkanes signals that the terrestrial organism(s) at the low latitude land response to the paleoclimate changes which may closely related to the decrease in the concentration of atmospheric CO2 and the ocean temperature during EOT. Therefore, the discrepancy in the δ13C composition of nalkanes may suggest that there was an significant shift or increase from C3 plant to C4 plant at the low altitude continental region of Maoming basin, which resulted in a remarkable change in the δ13C composition of sedimentary organic matter; while it is also possible that the positive excursion of organic matter might be due to the decrease in the concentration of atmospheric CO2 that gives rise to the δ13C composition of atmospheric CO2. Finally, this primary study suggests that more detailed research on the Maoming oil shale could provide some critical information to a better understanding of low latitude continental paleoclimate changes during EOT.

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    Characteristics and classification of tight oil pore structure in reservoir Chang 6 of Daijiaping area, Ordos Basin
    ZHOU Xiang, HE Sheng, LIU Ping
    2016, 23(3): 253-265. 
    DOI: 10.13745/j.esf.2016.03.029

    Abstract ( 2451 )   PDF (2342KB) ( 6281 )  

    Based on the data such as cast thin section, scanning electron microscope, Xray diffractometry and mercuryinjection, this paper has researched the micropore structure classification and evaluation of tight oil reservoir Chang 6 in Daijiaping area according to the feature and genetic analysis. The results showed that the reservoir space of reservoir Chang 6 is mainly characterized by intragranular dissolved pore and residual intergranular pore, and secondly by intergranular dissolved pore and debris dissolved pore associating with flaky, curved lamellar throat and necking throat mainly. The differences between rock fabric and clastic composition during sedimentation decided the original porosity and permeability, and influenced the diagenesis type and strength in the later stage. The results of the quantity calculation about the influence of diagenesis on reservoir quality suggest that compaction and cement of carbonate are the principal reason causing the damage of primary pore; whereas tectonic compression strengthened the heterogeneity of reservoir pore.We divided the porosity evolution into four stage, such as shallow burial cement, middle burial compaction porosity decrease, deep burial dissolve porosity increase and deep burial cement porosity decrease according to burial history analysis. Based on the correlation analysis among pore structure parameters and physical properties, we selected the largest connected throat radius, the main flow throat radius, sorting coefficient, displacement pressure and median pressure as the basis parameters for classification of reservoir. Further, this paper divides the reservoir of Chang 6 member into four types by Qcluster analysis, in which Ⅰ and Ⅱ types of reservoir pore structure are more favorable to be as development target play.

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    Spectra simulation of lunar regolith based on the Hapke radiative transfer model
    ZHAO Zhe, ZHOU Ping, YAN Bokun
    2016, 23(3): 266-278. 
    DOI: 10.13745/j.esf.2016.03.030

    Abstract ( 2322 )   PDF (1610KB) ( 6083 )  

    Due to so few of landing site on the moon, the ground truth data of lunar soil is scarce, which limits the further study of the lunar science. Thus to carry out spectral simulation of lunar regolith is almost the only feasible way to research the spectral mechanism of lunar regolith and improve the reliability of composition inversion of lunar regolith, which also is essential and beneficial supplement to the measured spectra of lunar regolith. We selected plagioclase, clinopyroxene, orthopyroxene, olivine, metallic iron, ilmenite, volcanic glass and agglutinate acquired from RELAB spectral library as mineral endmembers, and simulated spectra of LSCC lunar regolith based on Hapke radiative transfer model, using Newton interpolation and least square optimization method. The simulated spectra and the measured spectra fits well with the correlation coefficients more than 0.99 and the root mean square error at the magnitude of 10-3. The simulated mineral abundance shows a good linear fitting with the measured abundance. The simulated SMFe content has a distinct linear relationship with the relative maturity index Is/FeO. The simulated particle size strictly falls within the measured particle size range. The simulation accuracy of spectral parameters, such as absorption center wavelength and absorption area, was discussed. We also discussed the calculation method of optical constants used for spectra simulation with high precision.

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    General design of geophysical logging of the CCSDSK2 East Borehole in the Songliao Basin of Northeast China
    ZOU Changchun, XIAO Liang, NIU Yixiong
    2016, 23(3): 279-286. 
    DOI: 10.13745/j.esf.2016.03.031

    Abstract ( 2333 )   PDF (1378KB) ( 6188 )  

    CCSDSK2 East Borehole is the main borehole of China Continental Scientific Drilling Project in Songliao Basin, which is designed to reach a depth of 6400 m to penetrate Cretaceous strata. Its implementation is important for the research of the Cretaceous sedimentary environment and climate, for the achievement of new breakthroughs in oil and gas exploration, for the enhancement of the deepdrilling level and geophysical logging techniques, etc. Based on the scientific objectives and tasks of this project, combined with the design of drilling engineering and the characteristics of well conditions, the authors carried out the logging design of CCSDSK2 EastBorehole,intending to adopt the most advanced equipment to acquire log data. The adopted logging suits include comprehensive logging in openhole and cementevaluation logging in cased hole. Based on the situation of drilling times and programs, eight times of comprehensive logging and five times of cementevaluation logging are designed respectively, and comprehensive logging suits in different drilling times are different; taking into account the challenge of high temperature under the depth of 4500 m, logging items are designed including both required and selected ones. This logging design not only seeks to completely acquire all kinds of log data, but also conduces to flexibly deal with complex conditions of the borehole, which would be beneficial to the achievement of scientific goals.

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