水射流破碎南海含水合物沉积物数值模拟研究          下载免费PDF全文

潘栋彬  陈晨  杨林  靳成才  李曦桐  刘书源  陈勇  朱江 《探矿工程》2018,45(10):27-31

为研究高压水射流切割、破碎南海天然气水合物储层的过程,采用著名的LS—DYNA显示动力分析有限元程序,对淹没状态下,水射流破碎海底含水合物沉积物过程进行数值模拟研究,研究了不同射流速度对高压水射流作用下含水合物沉积物破碎效果的影响规律。随着射流速度的增大,冲蚀深度逐渐增大,两者呈线性递增关系。含水合物沉积物冲蚀体积是轴向冲蚀与径向冲蚀共同作用的结果,射流速度越大,对含水合物沉积物的轴向与径向冲蚀作用增强,加大了含水合物沉积物冲蚀体积递增速率。  相似文献   

大兴安岭呼中钼多金属矿床成矿流体特征及成矿机制          下载免费PDF全文

王升鹏  杨倩倩  齐忠友  陈晨  王童  钱鸿 《贵州地质》2018,35(2):118-124

大兴安岭呼中镇钼多金属矿床产于早白垩世碎裂花岗岩中,矿体形态似层状、脉状或透镜状。成矿阶段分为辉钼矿阶段、铜铅锌阶段、方解石阶段等3个阶段。本矿床中的包裹体主要有气液H_2O包裹体、气相H_2O包裹体、含子矿物H_2O包裹体,CO_2包裹体、CO_2-H_2O包裹体等五大类。辉钼矿阶段均一温度为209.2℃413.4℃,盐度ω(NaCleq)为0.53%16.53%,平均值7.3%,属中低盐度,成矿压力在53.3 68.5 MPa,相应的成矿深度为2 052 2 807 m;铜铅锌阶段为191.5℃351.0℃,盐度ω(NaCleq)为0.88%34.24%,平均值3.96%,属低盐度;方解石阶段207.2℃233.5℃,盐度ω(NaCleq)为3.55%4.18%,平均值3.77%,为低盐度。从辉钼矿阶段到铜铅锌阶段再到方解石阶段,温度及盐度逐渐降低。辉钼矿成矿压力在53.3 72.9 MPa,成矿深度为2 052 2 807 m。成矿过程中发生了CO_2-H_2O不混溶作用,这是导致辉钼矿沉淀的主要机制。矿床类型属中低温浅成热液型矿床。  相似文献   

华北克拉通北缘东段“开原岩群”的解体及重新认识     

赵辰  巩恩普  刘锦  宋淑娥  彭游博  崔育菘 《地质与资源》2018,27(3):209

根据近年来的同位素年代学资料,对分布于辽北地区的一套构造变质岩系（"开原岩群"或"清河镇岩群"）进行了重新认识和划分,并将其重新定义为清河构造混杂岩,由中太古代、新太古代、中元古代、新元古代、二叠纪等不同时代、不同构造环境的地质体组成.其中,中太古代、新太古代、中元古代岩石来自华北克拉通,而新元古代、二叠纪岩石则来自兴蒙造山带.将原沈家堡子岩组重新划分为新太古代变质表壳岩和中-新太古代变质深成岩,原板石沟岩组（或芦家堡子岩组）厘定为中元古代石门岩组,原照北山岩组重新划分为新元古代南平岩片和晚二叠世照北山岩组,将原佟家屯岩组和尖山子火山岩合并为晚二叠世佟家屯岩组.最后,提出了清河构造混杂岩带为华北克拉通与兴蒙造山带的界线以及古亚洲洋在华北板块北缘东段的最终闭合时间为中三叠世早期（约245Ma）的认识.  相似文献   

四川西昌盆地白垩纪恐龙足迹群的新发现     

童馗  邢立达  姜巽  彭光照  叶勇  江山  丑春永  李轲  李智武 《地质通报》2018,37(10):1771-1776

四川西昌盆地白垩系小坝组尚未发现骨骼化石记录,其白垩系恐龙动物群的信息全赖于足迹化石。2017年,在喜德县洛甘发现小坝组迄今最大型的恐龙足迹群。该足迹点保存了大量的兽脚类足迹。足迹保存条件较差,但具备了基本的形态学特征。总体来看,兽脚类足迹具有尺寸较小(8~13cm),中等中趾前凹(0.5~0.6)和第Ⅱ趾和第Ⅳ趾间较宽趾间角(70°~100°)的特征;少量足迹保存了跖骨垫。初步分析认为,洛甘兽脚类足迹与四川盆地夹关组的兽脚类足迹Eubrontes和Grallator形态类型相似,为两地在白垩纪中期具有类似的恐龙动物群的观点提供了新的证据。该发现对于西昌盆地的古气候、古地理和地层对比都具有重要的意义,足迹详细分类还有待进一步研究。  相似文献   

Investigation of gas content of organic-rich shale:A case study from Lower Permian shale in southern North China Basin,central China     

Wei Dang  Jin-Chuan Zhang  Xuan Tang  Xiao-Liang Wei  Zhong-Ming Li  Cheng-Hu Wang  Qian Chen  Chong Liu 《地学前缘(英文版)》2018,9(2):559-575

Measuring gas content is an essential step in estimating the commerciality of gas reserves. In this study,eight shale core samples from the Mouye-1 well were measured using a homemade patented gas desorption apparatus to determine their gas contents. Due to the air contamination that is introduced into the desorption canister, a mathematical method was devised to correct the gas quantity and quality.Compared to the chemical compositions of desorbed gas, the chemical compositions of residual gas are somewhat different. In residual gas, carbon dioxide and nitrogen record a slight increase, and propane is first observed. This phenomenon may be related to the exposure time during the transportation of shale samples from the drilling site to the laboratory, as well as the differences in the mass, size and adsorptivity of different gas molecules. In addition to a series of conventional methods, including the USBM direct method and the Amoco Curve Fit(ACF) method, which were used here for lost gas content estimation, a Modified Curve Fit(MCF) method, based on the 'bidisperse' diffusion model, was established to estimate lost gas content. By fitting the ACF and MCF models to gas desorption data, we determined that the MCF method could reasonably describe the gas desorption data over the entire time period, whereas the ACF method failed. The failure of the ACF method to describe the gas desorption process may be related to its restrictive assumption of a single pore size within shale samples. In comparison to the indirect method, this study demonstrates that none of the three methods studied in this investigation(USBM, ACF and MCF) could individually estimate the lost gas contents of all shale samples and that the proportion of free gas relative to total gas has a significant effect on the estimation accuracy of the selected method. When the ratio of free gas to total gas is lower than 45%, the USBM method is the best for estimating the lost gas content, whereas when the ratio ranges from 45% to 75% or is more than 75%, the ACF and MCF methods, are the best options respectively.  相似文献   

Upscaling permeability for three-dimensional fractured porous rocks with the multiple boundary method     

Tao Chen  Christoph Clauser  Gabriele Marquart  Karen Willbrand  Thomas Hiller 《Hydrogeology Journal》2018,26(6):1903-1916

Upscaling permeability of grid blocks is crucial for groundwater models. A novel upscaling method for three-dimensional fractured porous rocks is presented. The objective of the study was to compare this method with the commonly used Oda upscaling method and the volume averaging method. First, the multiple boundary method and its computational framework were defined for three-dimensional stochastic fracture networks. Then, the different upscaling methods were compared for a set of rotated fractures, for tortuous fractures, and for two discrete fracture networks. The results computed by the multiple boundary method are comparable with those of the other two methods and fit best the analytical solution for a set of rotated fractures. The errors in flow rate of the equivalent fracture model decrease when using the multiple boundary method. Furthermore, the errors of the equivalent fracture models increase from well-connected fracture networks to poorly connected ones. Finally, the diagonal components of the equivalent permeability tensors tend to follow a normal or log-normal distribution for the well-connected fracture network model with infinite fracture size. By contrast, they exhibit a power-law distribution for the poorly connected fracture network with multiple scale fractures. The study demonstrates the accuracy and the flexibility of the multiple boundary upscaling concept. This makes it attractive for being incorporated into any existing flow-based upscaling procedures, which helps in reducing the uncertainty of groundwater models.  相似文献   

Effects of Wave–Current Interaction on Salt Intrusion During a Typhoon Event in a Highly Stratified Estuary     

Wenping Gong  Yunzhen Chen  Heng Zhang  Zhaoyun Chen 《Estuaries and Coasts》2018,41(7):1904-1923

Wave–current interaction (WCI) is important in modulating hydrodynamics and water mixing in estuaries, and thereby the transport of water-borne materials. However, the effects of WCI on salt transport and salt intrusion in estuaries during storm events have been rarely examined. In the present study, we use a coupled atmosphere–ocean–wave–sediment transport (COAWST) modeling system to investigate the effects of WCI on salt intrusion in the highly stratified Modaomen Estuary during Typhoon Hagupit (2008). The model is validated by the measured wave, water elevation, and surface salinity data, and several diagnostic model experiments are conducted. WCI increases the storm surge by 0.8 m at the peak surge (25% of the total surge height). The wave-breaking-induced momentum flux and the Stokes drift increase the magnitude of the landward flow by 0.3 m s^?1 (30% of the total landward flow). In addition, the waves increase water mixing by 2–4 times compared with that without waves. Hence, WCI significantly increases the landward advective salt transport and decreases the steady shear transport. The net effect of the WCI is a significant increase of salt import and salt intrusion during the typhoon event. However, in the aftermath of the storm, the imported salt water is rapidly flushed out by the increased river discharge, and the estuary regains its stratification within one day.  相似文献   

Application of incomplete similarity theory to the estimation of the mean velocity of debris flows     

Tao Wang  Jiangang Chen  Xiaoqing Chen  Yong You  Niansheng Cheng 《Landslides》2018,15(10):2083-2091

The mean velocity of debris flow is one of the most important parameters in the design of mitigation structures and in quantitative risk analysis. This study develops a model to predict the mean debris flow velocity observed in the field by applying the incomplete similarity argument. An equation for estimating the Darcy-Weisbach resistance coefficient for debris flows with a volumetric sediment concentration larger than 0.19 is accordingly derived using 128 sets of observation data from nine Chinese gullies, in which both the effect of the volumetric sediment concentration and channel slope on resistance are considered. The derived equation is then verified and compared against five previously published equations by using 61 sets of published observation data from six gullies located in four countries. The applications of the proposed equation are discussed, and the improvements made using the proposed equation are clearly very significant when compared with the previously published equations.  相似文献   

Application of magnetic adsorbent with silicate and phenyl polymers to adsorb Rhodamine B     

C.-S. Chiou  H.-W. Chen  Z.-T. Chen 《International Journal of Environmental Science and Technology》2018,15(9):1879-1886

The extensive use of Rhodamine B (RhB) for textile, paper, pigment, food, cosmetic, and drug manufacturing and its indiscriminate disposal leads to serious human, biological, and environmental hazards. A magnetic adsorbent with silicate and phenyl polymers (Ph/SiO₂/Fe₃O₄) has been prepared to absorb RhB. The morphology and structure of the adsorbents have been characterized by TGA, XRD, FTIR, and adsorption–desorption measurement. The results revealed that Ph/SiO₂/Fe₃O₄ exhibited a paramagnetic behavior and could easily and quickly be separated from a suspension. The RhB adsorption behavior was almost pH independent due to the adsorption between the phenyl ring of Ph/SiO₂/Fe₃O₄ and RhB by π–π electron-donor–acceptor interactions. The adsorption behavior of RhB adsorption was in good agreement with the Langmuir adsorption isotherm, and the maximum adsorption capacity was 142.186 mg g^?1. Good desorption performance of Ph/SiO₂/Fe₃O₄ showed that this novel magnetic adsorbent cannot only be activated by ethanol extraction process but also reuse by the recovery of magnetic force.  相似文献   

Probabilistic calibration of a coupled hydro-mechanical slope stability model with integration of multiple observations     

Lulu Zhang  Fang Wu  Yafei Zheng  Lihong Chen  Jie Zhang  Xu Li 《Georisk: Assessment and Management of Risk for Engineered Systems and Geohazards》2018,12(3):169-182

Multiple types of responses, such as displacements, ground water level, pore water pressures, water contents, etc., are usually measured in comprehensive monitoring programmes for rainfall-induced landslide prevention. In this study, a probabilistic calibration method for coupled hydro-mechanical modelling of slope stability is presented with integration of multiple types of measurements. A numerical example of a soil slope under rainfall infiltration is illustrated to compare the effects of single and multiple types of responses on parameter estimation and model calibration. The results show that the soil parameters can be estimated with less uncertainty and total uncertainty bounds are narrower with multiple types of responses than with a single type of response. Model calibration based on multiple types of responses can compromise different responses and hence the means and standard deviations of model error are the smallest. A feasible correlation coefficient between soil modulus and permeability can be obtained from model calibration with multiple types of responses and single type of response as long as the responses include displacement data.  相似文献