北京房山应急水源地地下水数值模拟及河流渗漏量预测     

沈媛媛  辛宝东  郭高轩  纪轶群 《城市地质》2011,6(4):36-40

以北京房山岩溶水应急水源地为例,采用等效连续介质体概化地下水流系统,建立地下水流数值模型,评价地下水源汇项,分析地下水系统特征。运用MODFLOW中的河流（渠）子程序包,刻画地表河流和泉水与地下水的交换关系。经参数识别和验证,计算结果与实测数据拟合较好,能够比较准确的模拟水源地岩溶水系统。模拟和预测结果表明,水源地地区地下水与地表水联系密切,应急开采后,地下水系统由向河流排泄转变为河流渗漏补给地下水,可为应急水源地合理开发利用提供科学依据。  相似文献   

http://www.sciencedirect.com/science/article/pii/S1674987111000508   总被引：2，自引：0，他引：2  

Yanhua Zhang  J. Robinson  P.M. Schaubs 《地学前缘(英文版)》2011,2(3):449-461

This paper presents the results of a set of numerical models focussing on structural controls on hydrothermal mineralization.We first give an overview of natural phenomena of structurally-controlled ore formation and the background theory and mechanisms for such controls. We then provide the results of a group of simple 2D numerical models validated through comparison with Cu-vein structure observed near the Shilu Copper deposit(Yangchun,Guangdong Province, China) and finally a case study of 3D numerical modelling applied to the Hodgkinson Province in North Queensland(Australia).Two modelling approaches,discrete deformation modelling and continuum coupled deformation and fluid flow modelling,are involved.The 2D model-derived patterns are remarkably consistent with the Cu-vein structure from the Shilu Copper deposit,and show that both modelling approaches can realistically simulate the mechanical behaviours of shear and dilatant fractures.The continuum coupled deformation and fluid flow model indicates that pattern of the Cuveins near the Shilu deposit is the result of shear strain localization,development of dilation and fluid focussing into the dilatant fracture segments.The 3D case-study models(with deformation and fluid flow coupling) on the Hodgkinson Province generated a number of potential gold mineralization targets.  相似文献   

http://www.sciencedirect.com/science/article/pii/S1674987111000788     

Minghui Ju  Jianwen Yang 《地学前缘(英文版)》2011,2(4):577-582

This paper presents numerical investigation on the ore-forming fluid migration driven by tectonic deformation and thermally-induced buoyancy force in the Chanziping ore district in South China. A series of numerical scenarios are considered to examine the effect of meteoric water precipitation, the dip angle of the faults, unconformity surface, and thermal input on the ore genesis. Our computations reveal that the downward basinal fluid flow driven by extensional stress mixes with the upward basal fluid driven by the thermal input from depth at the junction of two faults at a temperature of about 200 C, triggering the precipitation of the Chanziping uranium deposit.  相似文献   

基于水电比拟方法的山东南四湖上级湖流场研究          下载免费PDF全文

汪嘉宁  吕红民  江文胜 《海洋与湖沼》2011,42(2):324-329

利用水电比拟方法模拟了南四湖流场结构。同时,基于HAMSOM模式,对其流场进行了数值模拟,所得结果与水电比拟结果一致,两者平均相关系数在0.94以上,表明水电比拟实验技术路线可行,流场基本结构准确。该方法适用于低流速大流场的模拟。流场结构分析表明,湖区流速在汛期为cm/s量级,非汛期仅为mm/s量级。其中,在南阳湖北部...  相似文献   

热带海气相互作用对大气BSISO年际振荡的影响     

林爱兰  LITim  李春晖  梁建茵  LUOJing-Jia 《海洋学报(英文版)》2011,30(4):62-73

利用卫星观测OLR资料以及海气耦合数值模拟试验结果,从每年波-频分析结果提取了各种传播模态的强度指数序列,分析了热带北半球夏季季节内振荡(BSISO)各种传播模态的年际变化谱特征,探讨了热带各海区海气相互作用对其影响。主要结果如下:赤道外西传波和印度洋北传波以准2 a为显著振荡周期,赤道东传波、南海北传波和西太平洋北传波则都包含准2 a和准5 a两种周期,南海北传波是5种指数中惟一以准5 a为最主要周期振荡的模态。热带印度洋、西太平洋、东太平洋各海区海气相互作用对各指数准2 a振荡、准5 a振荡既有加强作用,也有削弱作用。各海区比较而言,对赤道东传波准2 a和准5 a振荡、南海北传波准2 a和准5 a振荡起最大加强作用的是西太平洋海区海气相互作用;对赤道外西传波准2 a振荡、西太平洋北传波准2 a和准5 a振荡起最大加强作用的是印度洋海区海气相互作用。  相似文献   

Effect of slowly varying drift forces on the motion characteristics of truss spar platforms     

O.A. Montasir 《Ocean Engineering》2011,38(13):1417-1429

Spar platform has been regarded as a competitive floating structure for deep and ultra deep water oil and gas production. In this paper, an efficient methodology has been developed to determine the slow motion responses of slender floating offshore structures due to wave forces. Based on this methodology, a MATLAB program named ‘TRSPAR’ was developed to predict the dynamic responses in time domain and it was used in this study to obtain the numerical results of a typical truss spar platform connected to sea bed using nine taut mooring lines. The difference frequency forces were calculated using the principles of the extension of Morison equation for an inclined cylinder and the wave kinematics were predicted using hyperbolic extrapolation. Mooring lines were modelled as nonlinear springs and their stiffness was obtained by conducting the static offset simulation. Because of the lack of detailed calculations in literature, most of the equations used were derived and presented in this paper. The effects of the different sources of the second order difference frequency forces were compared for inertia and drag forces in terms of response spectra. To validate the TRSPAR code, its results were compared to results of a typical truss spar model test.  相似文献   

Numerical simulation of nearshore circulation on field topography under random wave environment     

Junwoo Choi  Sung Bum Yoon 《Coastal Engineering》2011

In order to investigate surf zone hydrodynamics through two-dimensional numerical simulations of nearshore circulation under random wave environment, a nearshore circulation model, SHORECIRC, and a random wave model, SWAN, were combined and utilized. Using this combined model, a numerical simulation of the October 2, 1997 SandyDuck field experiment was performed. For this simulation, field topography and an input offshore spectrum were constructed using observed data sets synchronized with the experiment. The wave-breaking model in SWAN was modified by using breaker parameters varied according to bottom slope. The simulation results were compared with the experimental data, which revealed a well-developed longshore current, as well as with results using other combinations which were SHORECIRC and its original monochromatic wave-driver, and SHORECIRC and the default of SWAN. The results from the novel combined model agreed well with the experimental data. The results of the present simulation also indicate that alongshore field topography influences shear fluctuation of longshore currents.  相似文献   

Numerical studies of methane production from Class 1 gas hydrate accumulations enhanced with carbon dioxide injection   总被引：2，自引：0，他引：2  

M.D. White  S.K. WurstnerB.P. McGrail 《Marine and Petroleum Geology》2011,28(2):546-560

Class 1 gas hydrate accumulations are characterized by a permeable hydrate-bearing interval overlying a permeable interval with mobile gas, sandwiched between two impermeable intervals. Depressurization-induced dissociation is currently the favored technology for producing gas from Class 1 gas hydrate accumulations. The depressurization production technology requires heat transfer from the surrounding environment to sustain dissociation as the temperature drops toward the hydrate equilibrium point and leaves the reservoir void of gas hydrate. Production of gas hydrate accumulations by exchanging carbon dioxide with methane in the clathrate structure has been demonstrated in laboratory experiments and proposed as a field-scale technology. The carbon dioxide exchange technology has the potential for yielding higher production rates and mechanically stabilizing the reservoir by maintaining hydrate saturations. We used numerical simulation to investigate the advantages and disadvantages of using carbon dioxide injection to enhance the production of methane from Class 1 gas hydrate accumulations. Numerical simulations in this study were primarily concerned with the mechanisms and approaches of carbon dioxide injection to investigate whether methane production could be enhanced through this approach. To avoid excessive simulation execution times, a five-spot well pattern with a 500-m well spacing was approximated using a two-dimensional domain having well boundaries on the vertical sides and impermeable boundaries on the horizontal sides. Impermeable over- and under burden were included to account for heat transfer into the production interval. Simulation results indicate that low injection pressures can be used to reduce secondary hydrate formation and that direct contact of injected carbon dioxide with the methane hydrate present in the formation is limited due to bypass through the higher permeability gas zone.  相似文献   

Analysis of formation pressure test results in the Mount Elbert methane hydrate reservoir through numerical simulation     

Masanori Kurihara  Akihiko SatoKunihiro Funatsu  Hisanao OuchiYoshihiro Masuda  Hideo NaritaTimothy S. Collett 《Marine and Petroleum Geology》2011,28(2):502-516

Targeting the methane hydrate (MH) bearing units C and D at the Mount Elbert prospect on the Alaska North Slope, four MDT (Modular Dynamic Formation Tester) tests were conducted in February 2007. The C2 MDT test was selected for history matching simulation in the MH Simulator Code Comparison Study. Through history matching simulation, the physical and chemical properties of the unit C were adjusted, which suggested the most likely reservoir properties of this unit. Based on these properties thus tuned, the numerical models replicating “Mount Elbert C2 zone like reservoir”, “PBU L-Pad like reservoir” and “PBU L-Pad down dip like reservoir” were constructed. The long term production performances of wells in these reservoirs were then forecasted assuming the MH dissociation and production by the methods of depressurization, combination of depressurization and wellbore heating, and hot water huff and puff. The predicted cumulative gas production ranges from 2.16 × 10⁶ m³/well to 8.22 × 10⁸ m³/well depending mainly on the initial temperature of the reservoir and on the production method.This paper describes the details of modeling and history matching simulation. This paper also presents the results of the examinations on the effects of reservoir properties on MH dissociation and production performances under the application of the depressurization and thermal methods.  相似文献   

The effect of the dominant polychaete Scolelepis squamata on nematode colonisation in sandy beach sediments: An experimental approach     

Tatiana F. Maria  André M. EstevesJan Vanaverbeke  Ann Vanreusel 《Estuarine, Coastal and Shelf Science》2011,94(3):272-280

The effect of an abundant sandy beach polychaete, Scolelepis squamata, on the colonisation of defaunated sediments by marine nematodes indicates that sandy beach fauna can be partially controlled by biological interactions within and across size groups. Experimental cores, equipped with windows allowing infaunal colonisation, were filled with defaunated sandy beach sediment containing two different treatments with and without S. squamata. These cores were inserted into microcosms filled with sediment with indigenous meiofauna collected from the field. The treatments were incubated in the laboratory at ambient temperature and salinity for 2, 7, 14 and 21 days, in order to follow the colonisation process of the defaunated sediments by the indigenous nematode fauna over time. Nematodes initially colonised both treatments, with abundances of up to 10% of the densities in the control; after 2 weeks, nematode densities in the cores without S. squamata surpassed the control densities. Nematode assemblages in both treatments were not species rich, and also differed in composition from the natural assemblages. The most successful colonising species, Enoplolaimus litoralis, was rare in the surrounding sediment, suggesting that colonisation was determined by species-specific characteristics such as body size, motility and feeding strategy. Initially the presence of macrofauna did not affect the nematode community composition, but after 2 weeks of the experiment, the presence of the polychaete seemed to facilitate the earlier establishment of non-opportunistic species.  相似文献