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Acta Geologica Sinica(English Edition) 2013年第3期87卷 767-776页

作者： ZHU Youhai HUANG xia FU Shaoying SU Pibo Oil & Gas survey China Geological Survey Institute of Mineral Resources Chinese Academy of Geological Sciences Guangzhou Marine geological survey

The Shenhu gas hydrate drilling area is located in the central Baiyun sag, Zhu I! depression, Pearl River Mouth basin, northern South China Sea. The gas compositions contained in the hydrate-bearing zones is dominated by methane with content up to 99.89% and 99.91%. The carbon isotope of the methane （δ^13C1） are -56.7%0. and -60.9%0, and its hydrogen isotope （δD） are -199%0 and -180%0, respectively, indicating the methane from the microbial reduction of CO2. Based on the data of measured seafloor temperature and geothermal gradient, the gas formed hydrate reservoirs are from depths 24-1699 m below the seafloor, and main gas-generation zone is present at the depth interval of 416-1165 m. Gas-bearing zones include the Hanjiang Formation, Yuehai Formation, Wanshan Formation and Quaternary sediments. We infer that the microbial gas migrated laterally or vertically along faults （especially interlayer faults）, slump structures, small-scale diapiric structures, regional sand beds and sedimentary boundaries to the hydrate stability zone, and formed natural gas hydrates in the upper Yuehai Formation and lower Wanshan Formation, probably with contribution of a little thermogenic gas from the deep sedments during this process.

关键词： natural gas hydrate methane microbial gas gas source migration South China Sea

Genesis of sandstone-type uranium deposits along the northern margin of the Ordos Basin,China

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Geoscience Frontiers 2020年第1期11卷 215-227页

作者： Ruoshi Jin Xueming Teng xiaoguang Li Qinghong Si Wei Wang Tianjin center China Geological SurveyTianjin 300170China Key Laboratory of Uranium Geology China Geological SurveyTianjin 300170China

Sandstone-type U mineral resources are among the important sources for nuclear *** U deposits in the Ordos Basin in China form part of the northern segment of the sandstone-hosted Central Asian Uranium *** types of mineralizations are recognized in this basin:"phreatic permeable type"and"interlayer permeable type",both exhibiting features equivalent to roll-front ***"interlayer permeable type"is widely accepted as the dominant mineralization type for sandstone-type uranium deposits within large-scale basins,also designated as the"interlayer oxidation zone type",based on the horizontal color zoning model representing changing redox *** we synthesize data from several drill holes within the Ordos Basin,which suggest that major Mesozoic tectonic movements controlled the evolution of the sedimentary system in the *** tectonic movements contributed to the formation of three angular unconformities and four parallel unconformities as inferred from the stratigraphic *** addition,other features such as vertical color zoning,paleo-channel controlled tabular or lentoid ore bodies(without roll-type)and a group interlayer horizontal zoning of altered minerals are also *** stratigraphic analysis indicates that the Ordos Basin generally witnessed four cycles of water level variations during *** the variations,three high water level and three low water level events were *** characteristics imply that the Ordos Basin went through multiple arid to humid climatic evolutions during *** the newly documented features with some novel concepts on the hydrodynamic mechanism for supergene ore-forming fluids,we propose a metallogenic model which invokes the importance of tectonic movements and water level fluctuations to explain the genesis of uranium deposits along the northern margin of the Ordos Basin.

关键词： Sequence stratigraphic analysis Hydrodynamic mechanisms Metallogenic model Tectonic history Ordos Basin

Improving reservoir volumetric estimations in petroleum resource assessment using discovery process models

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Petroleum Science 2009年第2期6卷 105-118页

作者： Osadetz Kirk G. geological survey of Canada

The reservoir volumetric approach represents a widely accepted, but flawed method of petroleum play resource calculation. In this paper, we propose a combination of techniques that can improve the applicability and quality of the resource estimation. These techniques include： 1） the use of the Multivariate Discovery Process model （MDP） to derive unbiased distribution parameters of reservoir volumetric variables and to reveal correlations among the variables; 2） the use of the Geo-anchored method to estimate simultaneously the number of oil and gas pools in the same play; and 3） the crossvalidation of assessment results from different methods. These techniques are illustrated by using an example of crude oil and natural gas resource assessment of the Sverdrup Basin, Canadian Archipelago. The example shows that when direct volumetric measurements of the untested prospects are not available, the MDP model can help derive unbiased estimates of the distribution parameters by using information from the discovered oil and gas accumulations. It also shows that an estimation of the number of oil and gas accumulations and associated size ranges from a discovery process model can provide an alternative and efficient approach when inadequate geological data hinder the estimation. Cross-examination of assessment results derived using different methods allows one to focus on and analyze the causes for the major differences, thus providing a more reliable assessment outcome.

关键词： Multivariate Discovery Process model sampling bias correction cross-validation Geoanchored method

Uranium mineralization formed through multi-stage superposition: Case of the Qianjiadian deposit in Songliao Basin, China

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Energy Geoscience 2021年第1期2卷 32-40页

作者： Zhenyan Chen Qingchun Li Mingyi Liu Bairong Song Minqiang Cao Miao Wang Liaohe Petroleum Exploration Bureau PanjinLiaoning124010China Department of Geology Northwest UniversityXi’an710069China xi'an center of geological survey CGSXi'an710054China

The Qianjiadian uranium deposit is located in the Kailu Depression of Songliao *** is a large-scale in-situ leachable uranium deposit of sandstone type and provides a typical case of the uranium deposits in the Songliao *** we analyze the impact of oil and gas on reduction alteration,and factors including low grade *** Qianjiadian uranium deposit is characterized as a typical rolltype deposit with interlayers in oxidized *** occurrence of reductive low-permeability sandstone in uranium reservoirs controls the morphology of the uranium-rich *** propose a metallogenic model involving multi-stage superposition characterized by“primary sediment enrichment-interlayer oxidation-superimposed transformation”.Our model would be helpful for formulating guidelines in the exploration for sandstone-type uranium deposits in the Songliao Basin.

关键词： Qianjiadian uranium deposit Sandstone-type uranium deposit Interlayer oxidation Hydrothermal transformation Metallogenic model

Failure mechanisms and risk mitigation of check dams on the Chinese Loess Plateau: A case study at the Gutun Gully

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Journal of Mountain Science 2022年第6期19卷 1509-1524页

作者： JIANG Rui-jun ZHANG Mao-sheng FENG Li SUN Ping-ping Department of geological Engineering Chang’an UniversityXi’anShaanxi 710054China Department of Civil Engineering School of Human Settlements and Civil EngineeringXi’an Jiaotong UniversityXi'an 710049China Key Laboratory for Geo-hazards in Loess Area Ministry of Natural ResourcesXi’an Center of China Geological SurveyXi’an 710054China

Loess is long-term aeolian dust deposition, characterized by loose structure, concentrated participle distribution and unstable mineral composition, and thus easy to cause extensive collapsibility and have general water sensitivity. To reveal the difference in water sensitivity between naturally intact(NI) loess and mechanically compacted(MC) loess used for the check dam, the transient water release and imbibition method(TRIM) was used to acquire the suction stress–expanded hydraulic characteristic curves for the NI and MC loess and explore possible approaches for formulating the potential of loess water sensitivity. Based on the Local Field of Safety(LFS) associated with slope stability, we constructed a finite element model of a check dam to depict its failure processes under different rainfall scenarios. The results revealed the strong water sensitivity in NI loess, while the MC loess retained a certain water-sensitive potential. This capacity depends on the ‘water sensitivity coefficient’ obtained from the suction-stress characteristic curve,which better presented the deformation potential of the two loess samples at different water content levels. In the context of LFS, we identified two failure patterns in the dam body that were involved in loess water sensitivity under hydromechanical conditions: rainfall erosion-induced shallow mudflow failure, and preferential-infiltration progressive failure. These patterns may provide new insights into dam-breakage mechanisms and potential chain effects of check dams on the Chinese Loess Plateau from the perspective of soil–water interactions, which is vital for predicting the position and timing of check dam failure, and mitigating risks.

关键词： Chinese loess Water sensitivity Suction stress Failure patterns Slope stability Check dam

Effect of modeling factors on the dissolution-diffusion-convection process during CO2 geological storage in deep saline formations

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Frontiers of Earth Science 2013年第2期7卷 238-256页

作者： WeiZHANG National geological Library of China (Geoscience Documentation center) China Geological Survey Beijing 100083 China

It is well known that during CO2 geological storage, density-driven convective activity can significantly accelerate the dissolution of injected CO2 into water. This action could limit the escape of supercritical CO2 from the storage formation through vertical pathways such as fractures, faults and abandoned wells, consequently increasing permanence and security of storage. First, we investigated the effect of numerical perturbation caused by time and grid resolution and the convergence criteria on the dissolution-diffusion-convection （DDC） process. Then, using the model with appropriate spatial and temporal resolution, some uncertainty parameters investigated in our previous paper such as initial gas saturation and model boundaries, and other factors such as relative liquid permeability and porosity modification were used to examine their effects on the DDC process. Finally, we compared the effect of 2D and 3D models on the simulation of the DDC process. The above modeling results should contribute to clear understanding and accurate simulation of the DDC process, especially the onset of convective activity, and the CO2 dissolution rate during the convection-dominated stage.

关键词： climate change carbon dioxide geologic sequestration density-driven convection reactive transport modeling grid resolution

Detrital Zircon Geochronology of Early Triassic Strata in the West Qinling Orogen:Implications for the Tectonic Evolution of the Paleo-Tethyan Ocean

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Journal of Earth Science 2024年第4期35卷 1087-1106页

作者： Zuochen Li xianzhi Pei Liyong Wei Guobing Liang Meng Wang Ruibao Li Lei Pei Chengjun Liu Youxin Chen Feng Gao xi’an Key Laboratory for Mineralization and Efficient Utilization of Critical Metals School of Earth Science and ResourcesChang’an UniversityXi’an710054China xi’an Mineral Resources survey center China Geological SurveyXi’an710100China School of Geology and Mining Engineering Xinjiang UniversityUrumqi830000China

The West Qinling Orogen(WQO)is located in the western part of the Qinling Orogen and in the transition zone of Qilian Orogen,Songpan-Garze Orogen and Yangtze Block,and also the key position of Triassic collision orogenic *** study of the Early Triassic strata in the WQO is contributed to analyze the closure process of the *** conducted LA-ICP-MS U-Pb dating studies on detrital zircons to determine the provenance,depositional age,and tectonic setting of the Early Triassic Longwuhe Formation in the Lintan area of the *** results show that the majority of the detrital zircons in the Longwuhe Formation are mainly magmatic origin and have characteristic of crust source *** lowest limit of sedimentation of the Longwuhe Formation is constrained to the Early Triassic,with the youngest detrital zircon age of 253±3 *** ages can be divided into five age groups:3346–1636 Ma,with two peak ages of ca.2495 and ca.1885 Ma;1585–1010 Ma,with a peak age at ca.1084 Ma;992–554 Ma,with a peak age at ca.939 Ma;521–421 Ma,with a peak age at ca.445 Ma;418–253 Ma,with a peak age at ca.280 ***,the sources of the Longwuhe Formation include the northern margin of the WQO,the Qilian Orogen(QLO)and the basement of the southern margin of the North China Block(NCB),of which the ancient basement of the southern margin of the NCB is the main source area of the Longwuhe *** with previous studies,we propose that the Longwuhe Formation was formed in a fore-arc basin,which is related to the closure of the A’nyemaqen-Mianlüe Ocean from the Early Permian to Early–Middle Triassic due to the northward subduction-collision of the Yangtze Block(YZB).This also indicates that the A’nyemaqen-Mianlüe Ocean has flat subduction characteristics.

关键词： West Qinling orogenic belt Early Triassic paleo-Tethyan Ocean geochronology zircon

The First Discovery of a Large Sandstone-type Uranium Deposit in Aeolian Depositional Environment

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Acta Geologica Sinica(English Edition) 2020年第2期94卷 583-584页

作者： MIAO Peisen JIN Ruoshi LI Jianguo ZHAO Hualei CHEN Lulu CHEN Yin SI Qinghong Tianjin center China Geological SurveyTianjin 300170China

The exploration depth of sandstone-type uranium deposits worldwide is mostly less than 700 m,and most of them occur in strata of fluvial facies(Adams et al.,1981;Jin et al.,2016;Hou et al.,2017).Only a few small uranium deposits have been reported in aeolian depositional environments(Isachsen et al.,1955;Li et al.,2001).In the Pcngyang Jingchuan region of the southwestern Ordos Basin,uranium ore bodies with large thickness and high grade in the aeolian sandstone of the Luohe Formation were newly found at depths from 700 to 1500 m,which have laid the foundation for increasing the uranium resources significantly in the Ordos Basin.

关键词： sandstone uranium mostly

Teleseismic waves reveal anisotropic poroelastic response of wastewater disposal reservoir

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Earth and Planetary Physics 2021年第6期5卷 547-558页

作者： Andrew J Barbour Nicholas M Beeler u.s.geological survey earthquake science centerusa

Connecting earthquake nucleation in basement rock to fluid injection in basal,sedimentary reservoirs,depends heavily on choices related to the poroelastic properties of the fluid-rock system,thermo-chemical effects *** constraints on these parameters outside of laboratory settings are rare,and it is commonly assumed that the rock layers are *** the Arbuckle wastewater disposal reservoir in Osage County,Oklahoma,high-frequency formation pressure changes and collocated broadband ground velocities measured during the passing of large teleseismic waves show a poroelastic response of the reservoir that is both azimuthally variable and anisotropic;this includes evidence of static shifts in pressure that presumably relate to changes in local *** azimuthal dependence in both the static response and shear coupling appears related to tectonic stress and strain indicators such as the orientations of the maximum horizontal stress and faults and *** dynamic strains from a nearby borehole strainmeter,we show that the ratio of shear to volumetric strain coupling is~0.41 which implies a mean Skempton's coefficient of A=0.24 over the plausible range of the undrained Poisson's *** these observations are made at relatively low confining pressure and differential stress,we suggest that the hydraulically conductive fracture network is a primary control on the coupling between pore pressure diffusion and elastic stresses in response to natural or anthropogenic sources.

关键词： poroelasticity dynamic strain anisotropy wastewater disposal Oklahoma induced seismicity

Earthquake swarms near eastern Himalayan Syntaxis along Jiali Fault in Tibet:A seismotectonic appraisal

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Geoscience Frontiers 2015年第5期6卷 715-722页

作者： Basab Mukhopadhyay Sujit Dasgupta Geodata and Database Division Geological Survey of IndiaCentral Headquarters geological survey of India

The seismotectonic characteristics of ten repeated earthquake swarm sequence within a seismic cluster along Jiali Fault in eastern Himalayan Syntaxis(EHS) have been *** swarms are spatially disposed in and around Yigong Lake(a natural lake formed by blocking of Yigong River by landslide) and are characterized by low magnitude,crustal events with low to moderate b ***:mb discriminant functions though indicate anomalous nature of the earthquakes within swarm but are considered as natural events that occurred under condition of high apparent stress and stress *** fault plane solutions of selected swarms indicate strike-slip sense of shear on fault planes;solution parameters show low plunging compression and tensional axes along NW-SE and NE-SW respectively with causative fault plane oriented *** steeply towards south or *** fault plane is in excellent agreement with the disposition and tectonic movement registered by right lateral Jiali *** process of pore pressure perturbation and resultant ’r—t plot’ with modelled diffusivity(D = 0.12 m^2/s) relates the diffusion of pore pressure to seismic sequence in a fractured poro-elastic fluid saturated medium at average crustal depth of 15-20 *** low diffusivity depicts a highly fractured interconnected medium that is generated due to high stress activity near the eastern syntaxial bent of *** is proposed that hydro fracturing with respect to periodic pore pressure variations is responsible for generation of swarms in the *** fluid pressure generated due to shearing and infiltrations of surface water within dilated seismogenic fault(Jiali Fault) are causative factors.

关键词： Seismic swarm Eastern Himalayan Syntaxis(EHS) Jial