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    20 September 2003, Volume 9 Issue 3
    Article
    A New Approach to Exploring for Anomalously Pressured Gas Accumulations: The Key to Unlocking Huge, Unconventional Gas Resources
    Ronald C.Surdam, Zun sheng-Jiao, Yuri Ganshin
    2003, 9(3):  307-338. 
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    Anomalously pressured gas(APG)accumulations,commonly denoted “basin-center” gas systems(BCGS),represent a huge,largely undeveloped gas resource.For example,in the Wind River Basin,Wyoming,which is approximately 8 500 mi2 in area,the USGS estimates the in-place anomalously pressured gas resource is 900 Tcf. The cumulative production to date from the anomalously pressured portion of the stratigraphic section in the Wind River Basin is less than 1 Tcf.This type of gas in-place to production imbalance is typical of all anomalously pressured,“basin-centered” gas accumulations.The huge, underdeveloped gas resources occurring in BCGS need to be more effectively exploited.In the past, the exploitation of APG resources has been difficult and costly,but recent successes in the Greater Green River and Wind River basins,W Y ,and relatively older successes in the Alberta,Denver-Julesburg,and San Juan basins,demonstrate that more effective exploitation is achievable.Most importantly,when success is achieved in the exploitation of an anomalously pressured gas accumulation,the financial awards can be outstanding.I agree that to more fully exploit the APG resources in so-called basin-center configurations will require new and more innovative exploration strategies,technologies, and diagnostic techniques,all with the dedicated objective of substantially increasing the rate and magnitude of convetting these gas resources to energy reserves. The research group at Innovative Discovery Technologies(IDT)has developed a new and effective w ay to efficiently explore and exploit anomalously pressured gas accumulations. Application of the IDT technology provides the operator,prior to drilling,with the following essential information:(1)the spatial distribution of gas-charged rock/fluid systems,including pressure compartment boundaries;(2)the location and nature of the regional pressure surface boundary,or boundary between normally and anomalously pressured fluid (either under-or overpressured);(3)the determination of gas and water content in the fluid;(4)the identification and spatial distribution of microfracture swarms;(5)the orientation and timing of faults;and(6)the nature of reservoir attributes. With the specialized information yielded by the IDT approach optimum drilling and completion practices can be designed and employed that will enable operators to avoid the many disastrous pitfalls currently associated with exploitation of gas.charged,anomalously pressured formations.
    Advances and Reviews on Research of Coalbed Gas Geology in China
    QIN Yong
    2003, 9(3):  339-358. 
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    Based upon the study of the representative publications in recent years,the advances on the basic geology of coalbed gas in China were reviewed in four aspects,i.e.,coalbed gas generation-evolution-migration,coal reservoir and its predication,pool-forming dynamic condition and its numerical modeling ,and coalbed gas reservoir mod el an d regional accumulation.Some topics for the study of coalbed gas geology in China in the near future,then are propose ,which include the coalbed gas supercritical absorption effect,energy equilibrium system and accumulation-emission mechanism ,evaluation theory and mod el for the effective resources,structural-drainage control to coal reservoir permeability,and superimposed field effect for the effective anequilibrium of coalbed gas-bearing system .
    Predication for the Occurrence of High Permeability Coalbed Gas Reservoirs With Tectonics Analysis
    ZHANG Jian-bo1 2, QIN Yong2, WANG Hong-yan1, CHEN Jin-gang2
    2003, 9(3):  359-364. 
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    With the Shan’xi Qinshui Basin as a case,the geological mechanisms of structures controlling the occurrence of coalbed gas reservoirs with high-permeability were studied through a comprehensive analysis of modem tectonic stress field and curvature.The results showed that the testing well permeability of the major lower Permian Shan ’xi Formation coal reservoirs is positively and exponentially correlated to the main maximum stress difference of modem tectonic stress field an d the structural fissures in the coal reservoirs occur mostly in the zones with the structural curvature more than 0.1×10-4 /m.The zones matched high curvature to high main stress difference in the central and southern basin extend in the NNW strike,where the coal reservoir permeability is relatively high.The tectonic stress affects coal reservoir substantially through controlling the open-close degree of the fissures in coal reservoir.
    Storing Characteristics of Jurassic Coalbed Gas in Junggar and Tuha Basins
    SANG Shu-xun1, QIN Yong1, GUO Xiao-bo1, CHEN Yu-hua2
    2003, 9(3):  365-372. 
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    Coalbed gas exploration and development of the low-rank coal reservoirs in the Jurassic continental basins of Northwest China is drawing more an more attentions .The reservoirforming mechanism is important for the exploration an d development of the coalbed gas because the coalbed gas store is one of the key geological processes.The results of this study indicate that there are high pore volume,high pore specific surface area,high free gas storing potential and low gas absorption in the low-rank coal reservoirs of the Jurassic continental basins in the Junggar and Tuha Basins and the gas storage quantity in the deep coal reservoirs might be remarkably higher.The shallow coal reservoirs pools primarily absorption gas , but in the deep coal reservoirs ,absorption,dissociation and dissolution gases may coexist.The structural elevation and traps might influence greatly the formation of deep coalbed gas pools. Concurrent exploration and development for both coalbed gas and normal natural gas is theoretically feasible,however,the deep coalbed gas reservoirs might be more valuable for the development.
    Coupling Correlation Between High-rank Coal Matrix Mechanic Effect and Coal Reservoir Permeability
    FU Xue-hai, QIN Yong, ZHANG Wan-hong
    2003, 9(3):  373-377. 
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    Based on the adsorbing-swelling experiments of coal samples,the self-adjusting effects of lean coal to antracite were revealed.Then,the influence of the effects on coal reservoir permeability was analysed and the coupling mathematical model between the effective-stress effect,coal matrix shrinkage effect an dpermeability was established .The degressive rule of high-rank coal reservoir permeability during the coalbed methane recovery and the geological significance of the discovery were discussed.
    Effects of Coalification on the Formation and Accumulation of Coa1-Bed M ethane:A Studying Case From Qinshui Basin
    FANG Ai-min1, HOU Quan-lin2, LEI Jia-jin1, LI Ji-1iang1, YANG Lu-wu3, HU Ai-mei3
    2003, 9(3):  378-384. 
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    By reviewing the current achievements in the studies of relationships between coal metamorphism, distribution and accumulation of the coalbed methane, we find that different types and degrees of coal metamorphism have different effects on the formation,transportation,and accumulation of coalbed methane.Mainly through affecting the formation an devolution of pore an d track system in the coal seams,coal metamorphism is one of the most important geological factors which control the distribution and accumulation of coalbed methane.With the Qinshui Basin as a case.we discussed how the metamorphism of high-rank coal controls the formation and accumulations of the coalbed methane,and proposed some suggestions for the exploration and development of the coalbed methane in this coal field.
    Geological Alalysis of Production History in Coalbed Methane Wells
    HE Wei-gang1, YE Jian-ping2
    2003, 9(3):  385-389. 
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    Production data of 25 coalbed methanne wells of Jincheng,Lu’an,Jiaozuo and Tiefa coalfields are used in a comprehensive study on permeability,gas saturation,condition of reservoir pressure drop-off,underground water system an d energy system of coalbed methane reservoir.Four types of typical production curve in combed methane wells are recognized.The author believe that necessary reservoir conductions of high production coalbed methane well are high permeability (>0.5 mD),high specific value of critical desorption pressure and reservoir pressure(> 0.6)and high gas saturation(>8O%).Variable combination between coal seam and stratum may control directly coalbed methane production.
    Geological History Model and Its Numerical Simulation of Coalbed Methane Emission for Multi-Coal Seams
    WEI Chong-tao, ZHOU Rong-fu
    2003, 9(3):  390-395. 
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    The geological history of coalbed methane (CBM) emission during the formation of CBM reservoir formation was studied through the design and simulation of the numerical model under the condition of multi-coal seams.Some principles for simplifying multi-coal seams into the upside, bottom.major and middle seams were suggested.A formula for adjusting the CBM emission coefficient in the simplified seams was established according to the lithological composition an dvariety of the wall rocks.The method for setting the boundary condition.In which the neighbor coal seams could be taken as the boundary of the inner seams, was discussed. The boundary condition was studied in the case that the source rock or coal seams occur above or under the simulated coal series .The geological and mathematical models of the CBM emission in multi-coal-seams then were set up an d used in a case study in the Qinshui Basin.
    Application of the Technique of Coal Facies Analysis to Evaluation of Coal Reservoir
    WANG Sheng-wei, CHEN Zhong-hui, ZHANG Ming, DUAN Lian-xiu, LUO Shan-guo
    2003, 9(3):  396-401. 
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    The pore-fracture system, permeability of the coal reservoir and the heterogeneity of the pore-fracture system and permeability are very important aspects of the coal reservoir evaluation .The permeability of the coal reservoir depends on the pore-fracture system of the coal reservoir,an d the pore-fracture system of the coal reservoir depends on coal rank,coal lithotypes and maceral. In a small districts, the coal rank is usually stable or changes regularly, the permeability of the coal reservoir is mainly related to the coal lithotypes and maceral.The coal lithotypes,organic maceral,minerals depend on environment during the peat formation.The evaluation an d forecasting of the pore-fracture system an d permeability of the coal reservoir may be carried out by coal facies analysis,in which the important contents are coal maceral,structure of maceral,sequence of coal lithotypes an d parting
    Structural Features of the Longmen Shan Fold and Thrust Belt and Development of the Western Sichuan Foreland Basin,Central China
    JIA Dong1, CHEN Zhu-xin1, JIA Cheng-zao2, WEI Guo-qi2, LI Ben-liang2, ZHANG Qie1, WEI Dong-tao1, SHEN Yang1
    2003, 9(3):  402-410. 
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    The Longmen Shan fold and thrust belt is a key region for the study of Meso-Cenozoic tectonic evolution of the China continent.This belt experienced at least two major tectonic events of the Late Triassic an d Early Cenozoic ages,and formed obviously two phases of the foreland basin and the foreland fold-thrust belt.In this paper,the structural features of the Longmen Shan fold belt are presented ,with both tw-dimensional seismic profiles and field data.The complex structures of the NE trending Longrnen Shan fold—thrust belt and its foreland in the western Sichuan basin are interpreted as being formed by southeast-directed thrusting.The wedge-shaped Longmen Shan belt,consisting of numerous thrust sheets and nappes,thrust over the western side of the Yangtze craton.In both structural geometry and relative timing of folding an d thrusting, the northern Longmen Shan is significant different from the southern Longrnen Shan.The Longmen Shan fold and thrust belt can he divided into two major segments:the northern Longmen Shan an d the southern Longrnen Shan .Several eastward-verging,rootless thrust sheets and imbricates of the Cambrian-Triassic rocks have been recognized in the northern Longrnen Shan .Evidence suggests that the northern Longmen Shan experienced two periods of major deformation in the late Triassic an d Cenozoic ages ,though the late Triassic deformation is mole significant than the Cenozoic.Farther south,these principal tectonic units in the southern Longmen Shan are represented by the basement—involved thrust structures ,and the frontal thrust structures Propagated east-ward and actually passed from the edge of the thrust belt into the foreland of the western Sichuan basin.Its major deformation started in the Late Cretaceous-Early Cenozoic and continues to the present. Contemporaneous with thrusting was the development of the western Sichuan foreland basin.Sedimentary features of the foredeep exhibit two-phase flexural loading occurred within the western Sichuan basin,an d suggest that the Late Triassic peripheral foreland basin extends along the foredeep of the Longmenshan belt,but the Late Cretaceous.Paleogene rejuvenated foreland basin is restricted in the southern part of the western Sichuan basin.
    Tectonic Characteristics and Basin Evolution of the Mohe Basin,Heilongjiang Province
    ZHANG Shun1 3, LIN Chun-ming2, WU Chao-dong1, YANG Jian-guo3
    2003, 9(3):  411-419. 
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    Studies have been conducted to analyze the stratigraphical sequence,tectonic characteristics and basin evolution of the Mohe Basin in Heilongjiang Province.The results suggest that the Mohe Basin is located in the collision sutures of E’erguna micro-plate and Siberian Plate,belonging to Mongolia-Okhotsk fold belt.Its foundation consists of the Triassic metamorphic rocks and the Cambrian granites,and the sedimentary covers are mainly terrestrial coal formation(Jurassic) and the volcanic rocks(Cretaceous)with a typical dual structure.Because of the closing of Mongolia an d Okhotsk Ocean and the collision of Siberian and E’erguna micro-plates ,the western part of the basin produced cover structure in the opposite direction,and the strata was shortened more than 64 km in the Early Jurassic.During the Early Jurassic and the Late Cretaceous,the basin was affected by west Pacific tectonic evolution and was in extension environment.The volcanic and faulted basin was formed be cause the volcanic activities took place on a large scale three times in the middle and western parts of the basin.Because the Mohe Basin has experienced two kinds of evolution i.e.,the Mongolia,Okhotsk and west Pacific ocean structural evolution,therefore,the basin is characterized by compression in west part,extensional,faulted structures in the middle and east parts.
    Relationship Between Ore-Control Fracture and Gold Deposits in Linglong Goldfield,Zhaoyuan,Shandong
    DU Song-jin1 2, LI Hong-xi2, ZHANG Qing-long1, DU Ju-min1, XIE Guo-ai1
    2003, 9(3):  420-426. 
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    The linglong goldmine is mainly controlled by the NEE and NE treading faults, whose forming and motion features are closely related to the activity of Tanlu Fault.The main ore bodies are concentrated on the combination parts of two groups of faults.In the early Mesozoic,this area was affected by the Tanlu Fault.The NNE treading Ling long Fault is a sinistral strike-skip moving fault.while the character of the NE treading Podouqing Fault is mainly squeezable and sinistral movements.In the late Early Cretaceous,the NNE treading faults was moving dextrally,while the NE treading fault was on sinistral movement.All these suggest the multi-periodicity and complexity in the motion of faults.The characters of tectonic rocks imply that the ore-control fractures have suffered two stages of transformation- the ductile stage an d the brittle stage.Ore bodies are mainly occurred in lower plates .The scale of ore body an d ore-control fracture are positively correlated .
    Sequence-Stratigraphic Framework of the Early to Middle Triassic and Evolution of Sedimentary-Facies and Paleogeography in the Nanpanjiang Basin and Its Adjacent Areas:Discussion on Evolutionary Process from the Dianqiangui Basin to the Nanpanjiang Basin
    MEI Ming-xiang, MA Yong-sheng, DENG dun, MENG Qing-fen, YI Ding-hong, LI Dong-hai
    2003, 9(3):  427-439. 
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    A large-scale drowning event occurred in the transitional period between the Permian and the Triassic and resulted in the demise of some carbonate platforms in the Nanpanjiang Basin and its adjacent areas.The research areas experienced an evolutionary process of sedimentary basin from the Dianqiangui Basin to the Nanpanjiang Basin in the Triassic.Accordingly, the Triassic period is a differential period of sedimentary facies in the research areas,which are marked by the spatial changes from the connective platforms to the turbidity basin with the development of the several isolated platforms.More particularly,oolitic banks of the early epoch are developed in some isolated platforms such as in the Jingxi platform and in the Nanning platform in the southern part of the Nanpanjiang Basin.Seine as the limestones of reef and beach in the margin of the attached platform,the limestones of oolitic banks in isolated platforms came to front. Despite the differences in the time-span and the architecture of facies-succession of third-order sedimentary sequences ,the process of the third-order relative sea-level changes reflected by the sedimentary-facies succession is generally synchronous.Therefore,six third—order sequences could be discerned in the Early and the Middle Triassic in the Nanpanjiang Basin.With the two types of facies-changing surfaces and two types of diachronisms in stratigraphic records as the key elements, the framework of sequence stratigraphy from the Early to the Middle Triassic in the Nanpanjiang Basin could be constructed. The sequence-stratigraphic framework and the relevant paleogeographical features of the Early to Middle Triassic reveal the formational and the evolutionary process of the Nanpanjiang Basin,and the paleogeographical features of the Late Triassic reflect the dying of the Nanpanjiang Basin. In the research areas,the Early Triassic can be grouped into three third-order sequences SQl,SQ2 and SQ3.The forming process of SQ1 represents a building process of a ramp carbonate platform not only in the attached platform but also in the isolated platform .The forming process of SQ2 and SQ3 reflects an evolutionary process of the carbonate platform from the ramp type to the rimmed-shelf type.Correspondingly,oolitic-bank limestones constitute the HSTs from SQl to SQ3 in the background of an isolated platform .A succession from the non-compensatory sediments to the compensatory sediments of turbidity basin is form ed in the settings of a deep-water basin. Three third-order sequences from SQ4 to SQ6 of the Middle Triassic reflect three obvious changing processes in the deepening-shoaling of sedimentary environment.Consequently,turbidity rock-series are form ed in the setting of a basin;ref limestones or bank limestones are developed in the margin of attached platform ,and bioherm limestones are formed in isolated platforms. In the transitional period between the Early and Middle Triassic,in concomitance with the strong volcanic activity,there was a large-scope fall of third-order sea level changes ,which generated the unconformity of the first episode of the Indosinian movement---the top boundary of SQ3.With the rise of the crust caused by Indosinian movement in the east part of the research area,“ the Xianggui Basin”is defined by Zhao et a1.(1996)Was gradually closed,thus a unified turbidity basin i.e,”the Nanpanjiang Basin”defined by Enos et a1.(1998)was formed in the Ladinian age in the Dian qiangui area.
    Middle and Upper Cambrian in the East of Guizhou Province
    WANG Xian1 2, ZHANG Xiu-1ian1, SUN Yu2, LIN Xun2, QIAN Tian2, Qu Wei2
    2003, 9(3):  440-449. 
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    Three 3rd-order sequences and eight system tracts are recognized in two outcrop sections of the Middle and Upper Cambrian in Danzai and Sandu,eastern Guizhou province.Because of the tectonic fluctuation activity,the sedimentary environments of the two outcrops changed and the Platform evolved from ramp shelf in the Middle Cambrian to rimmed shelf in Upper Cambrian.Since the late of Middle Proterozoic Era,the ocean crust evolved to continental crust gradually in Guizhou area.Therefore,there were two sedimentary models:a broad open sea shelf model with ramp platform and flat floor,formed in the Middle Cambrian;and a platform (ramp)-open sea(basin)sedimentary model,shaped in the Upper Cambrian.The sequence cycles was controlled by the evolution of regional tectonics,and the sedimentary sequence characters are very important to the analysis of sedimentary environment.
    Restudy on the Shahejie Formation Transgression of the Paleocene in Zhan-Che Sag(Jiyang Depression)
    GE Rui-quan1, SONG Chuan-chun2, CHUN Ping1, WANG Ru-1iang1, ZHANG Duo-wen1, XU Hong-ze1
    2003, 9(3):  450-457. 
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    Restudy of lithological and paleontologic analysis of Zhan-Che Sag in Jiyang depression implies:(1)abundances of primary glauconite are different in the 1st to 4th members the Cenozoic Shahejie Formation;(2)reef limestones were found in the eastern part of Zhanhua sag,and Cladosiphonia fossils were found in the top of 4th member of Shahejie Formation;(3)salty water Foraminifera were found through the whole Paleogene;(4)abundant ostracoda fossils were found deposited in the 1st member of Shahejie Formation in Oil well of Gudong 25 before glauconite occurred.These facts further prove that marine transgression happened in this area during the Paleocene.
    Equilibrium Principle and Mathematic Description for Source-Contacting Gas Accumulation
    ZHANG Jin-chuan1, ZHANG Jie2
    2003, 9(3):  458-466. 
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    The driving of water by natural gas in tight sands is an extremely a complicated process.The injecting of gas from the bottom of tight sands has the feature of piston-fashioned water driving when both porosity and permeability of the sands are homogeneous.The accumulation of gas will be typically source-contacting or root-sourced when the driving of water by gas is pistonfashioned, Typically,source-contacting gas or basin-centered gas will not be accumulated when the tight sands are of heterogeneous or even fractured ,since the piston-typed and replacement-fashioned driving of gas will occur in the same time.In this paper,we will discuss the accumulation conditions and equilibriums of source—contacting gas for typical and practical hypothesis.Conditions for the accumulation of source-contacting gases or rooting gases can be summarized into the regional existence of tight sands,abundant supplying of generated gas,directly contact between source rocks an d reservoirs,and integration of reservoirs an d seal rocks.As a result,the equilibrium equations for the formation of different types of source-contacting gases,or basin,centered gases are established respectively.Further more,the applications of equations is concisely discussed.The result indicates that the formation condition of typical source-contacting gas is not related to the height of gas column as in normal gas accumulation,instead,it is closely related to the buried depth.
    Application of Electromagnetic Wave Computerized Tomography to Testing Quality of Pile
    Ll Cai-ming, WANG Liang-shu, ZHONG Kai
    2003, 9(3):  467-473. 
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    Quality inspection of pile foundations,is very important in the field of geotectonic engineering,especially engineering evaluation of integrality and damage degree.Electromagnetic wave computerized tomography (EWCT) is a new geophysics method for quality inspection of pile foundations.The main technological objective of EW CT is to acquire 2D images of defect distribution in the pile foundation and to evaluate the quality of pile foundation.This paper designs and tests the observation system and technique of data collections in EWCT as well as data processing of EWCT to the quality inspection of pile foundations.With a practical engineering example of successful application,the paper illustrates the effectiveness of this method .In the engineering demonstration,through the field tests data,the author acquire the CT images derived from the data inversion,then combined the result of CT technology and the result of drilling survey data.The comparative result shows that EWCT has the advantages of higher precision and credibility.When the pile foundations have inhomogeneous defects of layers, this method can efficiently and accurately make precise image of the defects distribution between wells.Electromagnetic tomography levels is clear,defects distribution is obvious geologic data,the interior structure and quality qualitative analysis and quantitative analysis. and intuitive.Combining with other engineering of concrete can be evaluated accurately through qualitative analysis and quantitative analysis.
    Numerical Simulations of Pit Discharge and Uplift Pressure of the South Anchor Region of Runyang Bridge
    GUO Fei1, LIU Jian-1i2, ZHU Xue-yu1
    2003, 9(3):  474-480. 
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    The South Anchor of Runyang bridge is a super-deep foundation pit.In this paper, the hydrogeological sub-division is made based on systemic study of the fault,physical characters of rock mass,water abundance,and permeability.Then the numerical simulation of the pit discharge an d uplift pressure were conducted with M ODFLOW software.The simulated results indicate that the discharge would not induce tragically water bursting in the process of engineering excavation if the aquifer of Quaternary is excluded by using underground continuous wall or artificially ground freezing .But the effect of uplift pressure on the foundation stability should be considered because uplift pressure will affect the engineering stability of the South Anchor excavating directly.W e propose to solve the problem by using drainage holes .Drainage orientation.Drainage depth an d drainage availability are discussed.
    The Significance of the Discovery and Researches of the Homo erectus From Nanjing
    ZHANG Lu-jin
    2003, 9(3):  481-483. 
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    In 1993,two very important human skulls and a number of mammal remains of Middle Pleistocene age were discovered from the Huludong karst cave.Which is situated on the Tangshan Hills,about 26 km east of Nanjing.It is interest to note that the Homo erectus of Nanjing,especiously the skull No.1, from the Huludong karst cave is more complete than those from the Zhoukoudian (according to the present preserved materials).In 1992,the initial investigation of the Huludong karst cave was carried out by Mu Xinan,Xu Hankui,Mu Daocheng and Zhong Shilan .In 1993, the earliest relevant papers were published separately by Mu Xinan et a1.and Xu Qinqi et a1.They essentially reported for the first time that the Homo erectus No.1 was a young woman,21-35 years old.The mammals represented a northern fauna type of Middle Pleistocene age in China.Afterwards,in December of 2002,a comprehensive monograph 《Homo erectus from Nanjing》was published (Wu Rukang,Li Xingxue,Wu Xinzhi and Mu Xinan,eds.).It contains more than ten research fields.A series of valuable conclusions are drawn out and new evidences for the human evolution of China are also provided .
    Geochemical Alteration of Hydrocarbon Compositions During Migration and Accumulation and Its Controlling Factors
    ZHANG Zhi-huan1 2, DENG Zu-you3, WU Shui-pi2, CHANG Xiang-chun4
    2003, 9(3):  484-493. 
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    Geochemical characteristics of hydrocarbon in reservoir are not only controlled by the organic-phase,maturity and sedimentary environment of source rock,but also affected by many other geological and geochemical factors including biodegradation,water washing ,fluid/rock interaction and geochromatography(during hydrocarbon migration and accumulation),phase-controlling molecular fractionation (during hydrocarbon migration and entrapment)。thermal alteration,multiple charge and mixed of petroleum,dissemination(reservoir overprinting ,solubilization)and thermochemistry sulfate reduction,etc.,during petroleum migration and accumulation.In this paper,the influences of the geological and geochemical factors on the geochemical characteristics of petroleum , such as biodegradation an d water washing ,fluid/rock interaction and geochromatography,phase-controlling molecular fractionation,thermal alteration,multiple charge and mixed of petroleum,dissemination and thermochemical sulfate reduction。etc.are disccessed.
    New Ar-Ar Geochronologic Rocks in the Western Segment Data of Paleozoic Volcanic of Chinese Southern Tianshan
    GONG Fu-hua1, LI Yue-jun2, WANG Qing-hua3,HU Shi-ling3, HUANG Zhi-bin3, LUO Jun-cheng3
    2003, 9(3):  494-509. 
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    The samples were collected in the western part of Chinese Southern Tianshan Mountains.The rock types for Ar-Ar analysis are andesite in the Wupataerkan Group of the Silurian to Devonian age and quartz andesite breccia in the Kangkelin Formation of the Carboniferous to Permian age.The plate and isochron ages of the former sample are 427.70±0.60 Ma and 426.96±4.57 Ma respectively;and those of the latter sample are 288.16± 0.40 Ma and 289..18±2.02 Ma,respectively.The 40Ar-39Ar geochronologic date reported here provide new information for the study in the Chinese Southern Tianshan orogenic belt.