2018 Vol. 24, No. 3

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2018, 24(3): .
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2018, 24(3): 封二-封三.
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THE FORMING MECHANISM OF THE BAODI-TONGBAIZHEN TRANSFER ZONE IN THE JIZHONG DEPRESSION AND ITS OIL-GAS BEARING
ZHOU Congan, ZHAO Li, SUN Yuhao, LI Xiaodong, LIU Haijian
2018, 24(3): 293-300. doi: 10.12090/j.issn.1006-6616.2018.24.03.031
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Based on the 3D seismic data, through structural section interpretation, fault throw calculation, structural evolution analysis of balanced section and classification of transfer zone types, the formation mechanism of the Baodi-Tongbaizhen transfer zone in the Jizhong Depression is studied in this article. The results indicate that:the Baodi-Tongbaizhen transfer zone is classified as synthetic collinear-type with horst and transfer fault as the main internal structural styles, while the Hupoying fault and the Yangshuiwu fault provide the conjugate accommodation. The Baodi-Tongbaizhen transfer zone acted intensively in Es4 because of the maximum differential extension, and its active intensity decreased gradually in Es3-Es1. However, the transfer zone fell into weakening again in N-Q after strong reaction in Ed. Hydrocarbon source rocks and traps developed respectively in the strong and weak structural regions on the two sides of the transfer zone, and the transfer faults connected with source reservoirs, which makes the area a favorable oriented region for oil and gas exploration.
THE FAULT SEALING ANALYSIS OF THE PUTAOHUA OIL LAYER IN THE GULONG OILFIELD
ZHANG Chi, LI Tao, HU Jia, TIAN Miao
2018, 24(3): 301-308. doi: 10.12090/j.issn.1006-6616.2018.24.03.032
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Faults in the Gulong oilfield are extremely developed. The fault sealing ability plays an important role in controlling the oil and gas migration and accumulation in the study area, so the study of fault sealing is in favor of the prediction of favorable locations for oil and gas accumulation. Qualitative analysis were carried out on the fault sealing ability in the study area from the aspects of fault type, geometric characteristics and buried depth, focusing on the two sides lithology configuration, clay smearing and stress. The sealing evolution history of typical faults was also studied. The results show that the primary and tertiary faults have good sealing ability, while the sealing ability of the secondary faults is ordinary. The fault sealing ability of the nose structure is superior to that of the syncline fault, in which the fault sealing ability of Longnan nose structure is the best.
EVALUATING MEASURED IN-SITU STRESS STATE CHANGES ASSOCIATED WITH EARTHQUAKES AND ITS IMPLICATIONS: A CASE STUDY IN THE LONGMENSHAN FAULT ZONE
QIN Xianghui, CHEN Qunce, MENG Wen, TAN Chengxuan, ZHANG Chongyuan, FENG Chengjun
2018, 24(3): 309-320. doi: 10.12090/j.issn.1006-6616.2018.24.03.033
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Evaluating measured in-situ stress state changes associated with large earthquake events plays a crucial role in earthquake prediction using measured in-situ stress data, whereas typical examples were not stated systematically yet. In this study, the Qiaoqi and Yingxiu regions which contain measured in-situ stress data crossing two large earthquakes (the Wenchuan earthquake and the Lushan earthquake) were selected as examples to study this issue. The changes of the stress state before and after the Wenchuan and Lushan earthquakes in the Qiaoqi and Yingxiu regions were analyzed by comparing the magnitudes of gradient coefficient, characteristic indexes KHV (ratio of the maximum horizontal stress to vertical stress), KHh (ratio of the maximum horizontal stress to minimum horizontal stress), and μm (shear stress normalized by average stress) obtained before and after these two earthquakes. The results indicate that the average magnitudes of KHV, KHh, and μm obtained after the Lushan earthquake (QQ-14) in Qiaoqi region are larger than those obtained before the Wenchuan earthquake (QQ-99); and the mean magnitudes of these parameters obtained from QQ-99 are larger than those obtained after the Wenchuan earthquake (QQ-09). However, the evolution feature of gradient coefficient before and after these two earthquakes can be characterized by QQ-09>QQ-14>QQ-99. Based on above estimation, it was stated that the changes of KHV, KHh, μm can reflect the evolution trend of the regional tectonic stress filed in Qiaoqi region, while the gradient coefficient can not reflect the evolution feature accurately enough. The magnitudes of gradient coefficient, KHV, and μm obtained from measured in-situ stress data after the Wenchuan earthquake exceed those after this large earthquake in Yingxiu region, while the KHh shows contradictory trend. The tectonic stress evolution in Yingxiu region should be verified by supplementing additional stress data. Long-term measured in-situ stress data which can be compared is the key element in significant breakthrough of earthquake prediction using the change laws of stress state characteristics parameters. Conclusions drawn in this study is of great significance for tectonic stress field estimation and disaster prevention and reduction in Longmenshan region, and can provide reference for earthquake prediction research.
RESEARCH ON GROUND STRESS DISTRIBUTION RULES OF DEEP TIGHT VOLCANIC ROCK RESERVOIRS IN THE HUOSHILING FORMATION, XUJIAWEIZI FAULT DEPRESSION
MAO Zhe, ZENG Lianbo, QIN Longbu, ZU Kewei, LIU Guoping, TIAN He
2018, 24(3): 321-331. doi: 10.12090/j.issn.1006-6616.2018.24.03.034
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The XujiaweiziFault Depression is located in the north of the Songliao basin, and its deep Mesozoic Huoshiling formation is a dense volcanic gas reservoir with natural fracture development and strong heterogeneity of the stress distribution. The present ground stress orientation of single well is analyzed by induced fracture method and well diameter caving method, and the longitudinal distribution of present ground stress is calculated by acoustic logging method.The heterogeneous three-dimensional geological model is established according to the top-and-bottom surface maps, volcanic facies groups and fault distribution characteristics of the Huoshiling Formation. Based on the fitting and correction of dynamic and static rock physical parameters, the physical parameters of different lithofacies groups and fault rocks are determined in combination with experimental tests and existing research results, and the three-dimensional mechanical model is established. Ansys finite element numerical simulation software is used to establish the three-dimensional mathematical model of the Huoshiling Formation and to obtain the three-dimensional present ground stress distribution model by correlative calculation.The calculated results show that in the Huoshiling Formation the preferred orientation of the maximum horizontal principal stress is EW, with the stress values range from 86 to 110 MPa, and the minimum horizontal principal stress preferred orientation is SN, with the stress values range from 67 to 84 MPa. The simulation results show that the volcanic facies, characteristics of faults and structural relief have great influences on the present ground stress of the Huoshiling Formation, Xujiaweizi Fault Depression. Among them the horizontal principal stress orientation is greatly affected by the distribution of faults and the near-crater facies, while the value of the horizontal principal stress is controlled by them three. The horizontal stress in the lower position of the depression, the near crater facies and the fault ends are high.The results of present ground stress can provide important guidance for the next-stage of well networks arrangement, fracturing reformation scheme, horizontal well design and water injection management in the Xujiaweizi Fault Depression.
MODELING OF DEFORMATION-CRACKING PROCESSES OF GEOMATERIALS BASED ON A CONTINUUM-DISCONTINUUM METHOD: A CASE STUDY OF COMPACT TENSION TEST
WANG Xuebin, BAI Xueyuan, ZHU Mingze
2018, 24(3): 332-340. doi: 10.12090/j.issn.1006-6616.2018.24.03.035
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Geomaterials are easily subject to tensile cracking. To model effectively deformation-cracking processes of geomaterials, a continuum-discontinuum method is developed, which is a combination of the Lagrangian element method and the fictitious crack method. This method can be used to more accurately model the stress and strain fields and the complex transition process from the continuum medium to the discontinuum medium. To demonstrate the ability of this method, deformation-cracking processes of rock specimens under compact tension are modeled. The following results are found. Deformation-cracking processes of rock specimens under compact tension are as follows:firstly, the concentrated maximum principal stress is observed at the tip of the Ⅴ-shaped notch; secondly, nodes get separated, fictitious or real cracks extend, and the concentrated maximum principal stress is at the tip of the Ⅴ-shaped notch all the time; finally, the rock specimen is split to two parts. A rapid increase in the maximum unbalanced force corresponds to a nodal separation. Load-displacement curves exhibit strain-hardening phenomena at pre-peak. The peak of stress-strain curve decreases with an increase of the size of the rock specimen, which is consistent with the scaling law of Bazǎnt. Moreover, the post-peak stress-strain curve becomes steep with an increase of the size of the rock specimen. The present numerical results of rock specimens under compact tension are reasonable, indicating the apparent ability of the present continuum-discontinuum method to model the transition process from the continuum medium to the discontinuum medium.
GEOCHEMICAL CHARACTERISTICS OF GRANODIORITE PORPHYRY AND MINERALIZATION STUDY IN THE GAERQIN COPPER DEPOSIT, TIBET
HE Yangyang, WEN Chunqi, LIU Xianfan
2018, 24(3): 341-349. doi: 10.12090/j.issn.1006-6616.2018.24.03.036
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The rare earth elements (REEs) in granodiorite porphyry and zircon from the Gaerqin copper deposit of Tibet, China, were geochemically traced, and the mineralization was also studied. The total levels of REEs in granodiorite porphyry varied slightly (ΣREE=48.64×10-6~78.12×10-6) with LREE/HREE=8.67~11.68. All samples were featured by a right-leaning distribution with enrichment in light REEs (LREEs) and depletion in heavy REEs (HREEs), δEu changed from weak negative anomaly to weak positive anomaly, which is due to the gradual weakening of negative Eu anomalies caused by crystallization differentiation and a weak positive Eu anomaly in the process of the partially remelting growth of the angled magma in the crust. The zircon was found with typical oscillatory zones, large total REE levels (ΣREE=735.78×10-6~6792.10×10-6), LREE depletion, HREE enrichment, evident Ce positive anomaly and weak negative Eu anomaly. This is because under the action of mantle fluid, heavy rare earth elements and Ce are more likely to enter the lattice of zircon than other light rare-earth elements. The weak negative abnormality of Eu is caused by oxidation and leaching of the late diagenetic rock mass. Comprehensive analysis reveals that the mantle fluid action endowed the granodiorite porphyry with the characteristics of crust-mantle mixing or even ore-formation. Meanwhile, the matter-energy exchange between magma and surrounding rocks accounted for the metamorphic sandstone ore-formation.
GEOLOGICAL MODEL FOR PROSPECTING PREDICTION IN "TRINITY" PROSPECTING AREA IN THE XIAOQINLING GOLD DEPOSIT IN SHANNXI AND ITS PROSPECTING SIGNIFICANCE
ZHANG Huanhuan, CHEN Hong, BAI He, LI Changshou, DONG Hongyi, LIU Xiaolong
2018, 24(3): 350-370. doi: 10.12090/j.issn.1006-6616.2018.24.03.037
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To solve the key problems to prospecting breakthrough, on the basis of the theory of prospecting prediction in exploration area, by conducting works such as structural-alteration special mapping, typical deposits analysis, the ore-forming geological bodies, the metallogenic structures, the metallogenic structural surface and the characteristics of mineralization of quartz vein type gold deposits in the Xiaoqinling gold fields are studied. On the basis of comprehensive analysis and research, the "trinity" prospecting prediction model is constructed.In combination with rock geochemical survey results, 13 prospecting target areas are delineated, including two which reveal industrial orebodies verified by engineering preliminary evidence, identifying that the "trinity" prospecting prediction model has preferable performance in quartz vein type gold deposits in the Xiaoqinling gold fields and practical guiding significance in the new round of "exploring deep deposit" work.
THE RECOVERY OF PROTOTYPE BASIN AND ITS CONTROL OVER THE DEPOSITION IN THE LOWER THIRD SUB-MEMBER AND FOURTH MEMBER OF THE SHAHEJIE FORMATION IN THE SOUTH SLOPE ZONE OF THE LAIZHOUWAN SAG
WANG Qiming, HUANG Xiaobo, ZHOU Xiaoguang, LIU Rui, LI Xiaohui
2018, 24(3): 371-380. doi: 10.12090/j.issn.1006-6616.2018.24.03.038
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The south slope zone of the Laizhouwan Sag in the late stage has been reformed in many large-scale tectonic movements, resulting in the unclear appearance of the original basin and the unclear distribution of the sedimentary system. Based on the tectonic evolution analysis as the main line, through seismic interpretation, sound wave time difference method and trend thickness method, prototype basin at the sedimentary period and its configuration relationship have been recovered in the lower third sub-member and the fourth member of the Shahejie Formation at the early paleogene, and the planar distribution and controlling factors of different sedimentary system have been cleared. Study showed that:(1)At the sedimentary period of the fourth member of the Shahejie Formation, the whole south slope zone of the Laizhouwan Sag were lifted and dropped due to block differences caused by fault extension, in the west three east-west spreading fault trough were formed by two groups of east-west trending faults and the east and south areas were the uplift areas of the Weibei salient.The early faults resulted in the palaeogeomorphology differences in the east and west. (2)At the sedimentary period of the lower third sub-member of the Shahejie Formation, the whole south slope zone went through rapid settlement and the west part was uplifted by the differences between the east and west faults, forming a local highland. Part of the eastern Weibei salient submerged in water later, forming broad platform. (3)Different provenance supply systemcontrolledthe differential distributionin Fan delta and braided river delta of the fourth member of the Shahejie Formation. Geomorphology together with the provenance supply differentiation controlled the development of lacustrine carbonate rocks and weathered eluvial facies and their vertical distribution in the lower third sub-member of the Shahejie Formation. The development and distribution of sedimentary systems have an important response relation to basin prototype.
MAIN TYPES AND HYDROCARBON EXPLORATION DIRECTION OF THE PALEO-UPLIFTS IN THE QAIDAM BASIN
ZENG Xu, TIAN Jixian, ZHANG Guoqing, ZHAO Jian, WU Pei, WANG Wei
2018, 24(3): 381-390. doi: 10.12090/j.issn.1006-6616.2018.24.03.039
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The paleo-uplifts in the Qaidam Basin are widely distributed and have great exploration potential. In order to indicate the exploration direction of the Qaidam Basin, the structural styles, sedimentary characteristics, evolution stages, kinematic characteristics and reservoir-forming laws of the main paleo-uplifts are summarized in this article through the interpretation of seismic data and the example analysis of discovered hydrocarbon reservoirs in paleo-uplifts in recent years. The paleo-uplifts in the basin are divided into 4 main types:stable type, active type, residual type and extinction type. At the same time, the distribution of paleo-uplifts in the basin has a certain regular pattern:the paleo-uplifts mainly developed on both sides of the deep faults, and the boundary conditions of different properties of basin determined the type of the paleo-uplift. The paleo-uplifts have superior reservoir forming conditions in the migration and accumulation of hydrocarbon, reservoir types, trap types, transportation conditions and preservation conditions etc. Therefore, two favorable exploration directions of the paleo-uplifts in the Qaidam Basin are confirmed:one is tapping the potential of the discovered hydrocarbon fields; the other one is the piedmont tectonic belt with relatively good reservoir conditions on the basin margin.
SEISMIC IDENTIFICATION AND PREDICTION OF C5 CHANNEL SANDSTONE IN THE CARBONERA FORMATION, LLANOS BASIN, COLOMBIA
ZHENG Liandi, YANG Jiangfeng, YUAN Liansheng, YANG Qilin, FENG Fang, LI Yang, MA Yongqiang, HU Junfeng
2018, 24(3): 391-398. doi: 10.12090/j.issn.1006-6616.2018.24.03.040
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The channels developed in the Micocene Carbonera formation in the eastern part of the Llanos basin, Columbia, are so favorable reservoir that the accurate descriptions for these channels are key issues in this area. Guided by the simulation of wave equation, the seismic identification mode for channel sand is established. The distribution of the channels is then predicted with RGB mixing frequencies data slices and sensitive attributes. Eventually, the thickness and porosity of sand body are quantitatively described, using constrained sparse impulse inversion and geostatistical inversion. In our study, five favorable lithologic traps of channel sandstone are described in detail. The width of channel is about 322~830 m, and the thickness for channel sand (with porosity larger than 18%) is 35.05 m, which make this channel sand favorable prospecting areas. The result of the drilling W2 verifies the validity of the technique and the reliability of the reservoir description, which provides a new direction for exploration and development in the next step.
PHYSICAL MODEL EXPERIMENTAL STUDY ON DEFORMATION AND FAILURE OF OVERLYING ROCK SLOPE UNDER THE CONDITION OF STEEP COAL SEAM MINING
HE Kai, GAO Yang, WANG Wenpei, ZHU Sainan
2018, 24(3): 399-406. doi: 10.12090/j.issn.1006-6616.2018.24.03.041
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Major rockslide is the main type of geological hazards in the mining mountainous areas of southwestern China. The failure modes and behaviors of this kind of rockslides are complex. Taking the Jiguanling landslide as an example, centrifuge modelling was taken to analyze the failure mechanism of a steep-dip carbonate slope which was induced by goaf in this study. With the model plate of coal seam was pulling out, the overlying strata began to move and dislocate under centrifugal acceleration. The model rock slope failed completely when the model plate was pulled out about 150mm.The experimental results show that the deformation tendency of bending and toppling appeared in steep-dip and layered limestone slopes by gravity. With the underground mining of coal seams, overlying steep-dip and layered rock slope lost its support, then strata got separated and tension fissures were generated. These rock strata were toppled due to severe deformation. The underlying stable rock mass was squeezed by the toppled overlying strata, and shear failure occurred. In the end, the Jiguangling rock slope was failed with the composite mode of toppling-sliding. This study could be a guide of early identification and failure mechanism analysis for major rockslides in mountainous area of southwestern China.
REAEARCH ON THE MECHANISM OF THE INFLUENCE OF DYNAMIC LOAD OF HIGH-SPEED TRAIN ON LAND SUBSIDENCE SUBJECTED TO FAULT EFFECT: A CASE STUDY OF THE HUAILAI SECTION OF THE BEIJING-ZHANGJIAKOU HIGH-SPEED RAILWAY
WANG Miaomiao, FENG Chengjun, QI Bangshen, MENG Jing, ZHANG Peng, REN Siqi, TAN Chengxuan
2018, 24(3): 407-415. doi: 10.12090/j.issn.1006-6616.2018.24.03.042
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The Huailai section of Beijing-Zhangjiakou (BZ) high-speed railway is located in the compound position of the Huaizhuo basin and Yanfan basin. The ground subsidence resulted from the difference of engineering geological characteristics of soil and sliding of buried faults in the basin will undoubtedly threaten the safe operation of BZ high-speed railway. Using numerical simulation to study the mechanism of the influence of dynamic load of high-speed train on land subsidence subjected to fault effect, the 2D geological model of soils in the Huailai section of BZ high-speed railway is established based on the field data of engineering geological boreholes and geophysical exploration in this study. The results indicate that the dynamic load of the train mainly affects the soil within the depth of 50m, with increasing displacements accompanying decreasing train velocities and increasing train mass. Under both the dynamic train load and fault slip, the settlement of the soil mainly affected by the dynamic train load tends to be mainly controlled by the fault slip as the depth increases. And the settlement of the soil below 50m is controlled by the fault slip. What's more, the settlement of soil around the fault in the hanging wall is larger than that in the footwall at the same distance from the fault.
APPLICATION OF TRANSIENT ELECTROMAGNETIC METHOD IN COLLAPSE HAZARD OF GOAF: TAKE THE INVESTIGATION OF THE GOAF IN SHENDONG COAL MINE AS AN EXAMPLE
GONG Peili, LI Wei
2018, 24(3): 416-423. doi: 10.12090/j.issn.1006-6616.2018.24.03.043
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A large number of unknown goaf areas formed in the random mining area of coal mine area, which are the causes of geological disasters such as ground collapse and ground fissure. In coal mining areas, underground caves are mainly coal mine goaf areas, showing the condition of being filled and not filled with accumulated water under the influence of hydrogeological conditions and exploration time. Due to the influence of hydrogeological conditions and mining time, the goafs present two statuses:filled and not filled with water. By using transient electromagnetic method, the goafs in Shendong mining area were investigated and explored, and the most primitive normalized secondary potential was used to explain the goafs filled and not filled with water. According to the time length of underground cavity development and the level of accumulated water, it will present high or low resistivity anomaly, showing striking features. It provides an example for the application of transient electromagnetic method in the exploration of goaf and goaf filled with water, and it is of great significance to predict and prevent the collapse geological disaster caused by the goaf.
ANALYSIS ON INTERNAL DYNAMIC GEOLOGICAL GENESIS OF SHALLOW LANDSLIDE IN QIN-BA MOUNTAIN AREA
XIONG Wei, LIU Ke, FAN Wen
2018, 24(3): 424-431. doi: 10.12090/j.issn.1006-6616.2018.24.03.044
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Taking the Diangou shallow landslide in Qin-Ba Mountain Area as an example, deformation destruction characteristics and internal dynamic geological genesis are analyzed in detail and multi-scale through regional macrostructure, side slope microstructure and rock microstructure. The study results show that the formation mechanism of shallow landslides in Qin-Ba Mountain Area is closely related to the internal dynamic geological conditions. Landslides usually developed in weak metamorphic areas and affected by regional tectonic activities. Folds, faults and other macro-structures were continuously and crossly distributed in the area which resulted in the deformation, elongation and shear of minerals in the rock, forming a ductile shear zone and a large number of micro-cracks. The filling and intersecting of multi-stage cracks made the rock mass more deteriorated. When the stress exceeded the rock strength, a series of micro-deformation occurred in the internal lamellar structure, such as bending, breaking and fracturing, which are the main deformation and failure modes of metamorphic rocks. The oblique crossing of faults and landslides, the same direction and inclination of the rock layers and folds with the slope aspect, providing a good forming condition of landslide. This relatively fragile geological environment affected by external factors, such as human activity and heavy rain, can easily lead to shallow landslides. It would be serious threats for nearby residents and constructions.
MODELLING TEST ON THE MECHANICAL PROPERTIES OF PRE-STRESSED LATTICE FRAMED ANCHOR STRUCTURE
SONG Jun, LIANG Jiong, SHI Shengwei, CHENG Yingjian
2018, 24(3): 432-438. doi: 10.12090/j.issn.1006-6616.2018.24.03.045
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Lattice anchoring is one of the frequently used prevention technologies for slope and landslide engineering. A large-scale physical model test was adopted to explore the interaction of actual mechanics characteristics of lattice frame anchorage in the detritus soil slope. Using the compacted clay filling the indoor model experiment groove to simulate the landslide mass, and designing the lattice beams with the ratio of similitude 1:2.5, which revealed the whole deformation process in lattice beams of pre-stressed lattice anchorage system under the action of pre-stress, we monitored parameters of the soil pressure, stress of lattice and displacement of lattice. On the basis of analysis about stress-strain data and deformation signs, the following results are obtained:The deformation of the anchor points at the boundary of the lattice were more obvious than those of the interior, and also fractured nearby, in addition, the shape of deformed cross-beam was just like an arch bridge; The stress on each beam was near the inverted triangle distribution which was maximum at the beam crossing points; The stress distribution of the anchor points was linearly decreasing from the top to the bottom. The above research could provide some reference for engineering optimization design.