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921.
Comparison of Galerkin-type discretization techniques for two-phase flow in heterogeneous porous media 总被引:1,自引:0,他引:1
A comparison of Standard Galerkin, Petrov-Galerkin, and Fully-Upwind Galerkin methods for the simulation of two-phase flow in heterogeneous porous media is presented. On the basis of the coupled pressure-saturation equations, a generalized formulation for all three finite element methods is derived and analysed. For flow in homogeneous media, the Petrov-Galerkin method gives excellent results. But this method fails miserably for problems with heterogeneous media. This is because it is not able to capture correctly processes that take place at interfaces when, for instance, the capillary pressure-saturation relationship after Brooks and Corey is assumed. The Fully-Upwind Galerkin method is superior to the Petrov-Galerkin approach because it is able to give correct results for flow in homogeneous and heterogeneous media for the two models of van Genuchten and Brooks-Corey. The widely used formulation which is correct for the homogeneous case cannot be used for heterogeneous media. Instead the straightforward approach of gradpc in combination with a chord-slope technique must be utilized. 相似文献
922.
Lithospheric Geothermal Structure in Yunnan, China 总被引:2,自引:0,他引:2
Zhou Zhenheng Xiang Caiying and Deng WanmingSeismological Bureau of Yunnan Province Kunming China Institute of Geology Chinese Academy of Sciences Beijing China 《中国地震研究》1998,(1)
In this paper,the characteristics of the lateral variations of the deep heat flow and Hthospheric geotemperature distribution in Yunnan have been studied,and the lithospheric geothermal structure has been divided into three types,i.e.the geothermal structure in the typical modern tectonically active region,transitional geological region and stable geological region.Finally,the relationship between the geotherm and seismicitv has been discussed. 相似文献
923.
淮南煤矿塌陷区煤矸石填充复垦及其对环境的影响 总被引:18,自引:0,他引:18
在分析淮南矿区煤矸石和地面塌陷现状的基础上,探讨用煤矸石填充塌陷区的意义及其对环境的影响。 相似文献
924.
大型天然水体的环境效应研究 总被引:1,自引:0,他引:1
柴贺军 《地质灾害与环境保护》1998,9(2):7-12
结合典型实例,论述大型天然水体--堰塞湖从形成到消亡过程中产生的灾害链和环境效应链,包括堰塞湖的淹没、边岸再造、堰塞沉积物、次生洪水、永久性不良地质环境的灾害和环境效应对人民生命财产的威胁,以及对水利水电、航运、公路和铁路工程的不良影响。 相似文献
925.
W.S. Fyfe 《Gondwana Research》1998,1(3-4):315-318
The most basic solid earth resources for use by man include construction materials, energy resources, metals, ceramics, soils. With the exception of construction materials, the formation of economic mineral deposits and soils involves the thermal or gravity driven flow of various types of geofluids. The search for mineral deposits thus involves the understanding of the exact nature of fluids, their mass and flow patterns. Given the giant thermal disturbances associated with the formation and destruction of Gondwana, it must be no surprise that these regions contain very significant mineral resources on a large scale. 相似文献
926.
A three-dimensional, three-phase numerical model is presented for simulating the movement of immiscible fluids, including
nonaqueous-phase liquids (NAPLs), through porous media. The model is designed to simulate soil flume experiments and for practical
application to a wide variety of contamination scenarios involving light or dense NAPLs in heterogeneous subsurface systems.
The model is derived for the three-phase flow of water, NAPL, and air in porous media. The basic governing equations are based
upon the mass conservation of the constitutents within the phases. The descretization chosen to transform the governing equations
into the approximating equations, although logically regular, is very general. The approximating equations are a set of simultaneous
coupled nonlinear equations which are solved by the Newton-Raphson method. The linear system solutions needed for the Newton-Raphson
method are obtained using a matrix of preconditioner/accelerator iterative methods.
Because of the special way the governing equations are implemented, the model is capable of simulating many of the phenomena
considered necessary for the sucessful simulation of field problems including entry pressure phenomena, entrapment, and preferential
flow paths. The model is verified by comparing it with several exact analytic test solutions and three soil flume experiments
involving the introduction and movement of light nonaqueous-phase liquid (LNAPL) or dense nonaqueous-phase liquid (DNAPL)
in heterogeneous sand containing a watertable.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
927.
The Judea Group, a limestone and dolomite karstic aquifer of late Albian–Turonian age, is one of the most important sources
of water in Israel. In the western part of the country, the Judea Group aquifer is also known as the Yarkon–Taninim basin.
In the northern Negev, the Judea Group is a recipient for fresh water flowing southward from the Hebron Mountains and of brackish
paleowater flowing northward from Sinai. Very little is known of the hydraulic properties of this aquifer. In order to outline
assumed natural flow paths that existed in this karstic environment prior to groundwater exploitation, use was made of lithological,
structural, and paleomorphological features. A detailed hydrogeological conceptual model of the Judea Group aquifer in northern
Negev was established by the geological interpretation of high-resolution seismic reflection and by analysis of lithological
evidence from boreholes. Isopach, isolith-contour, and isolith-ratio maps were compiled for the main lithological components.
Increase in transmissivity values is inversely proportional with the cumulative thickness of argillaceous components. The
lithological and hydraulic evidence provides the basis for subdividing the subsurface into distinctive permeability zones
for the upper and lower sections of the aquifer; for outlining possible preferential groundwater flow paths for both subaquifers;
and for improving understanding of groundwater-salinty variations that result from lithological variability, direction of
groundwater flow paths, groundwater flow rates, and the duration of rock/water interactions. In an earlier conceptual model
of the basin, the Judea Group aquifer was regarded as a continuous and undisturbed entity. The present study reveals an intricate
groundwater flow pattern that is controlled by lithological and structural factors that create zones of preferential flow.
This interpretation bears on the overall evaluation of groundwater resources and their management and exploitation.
Received, December 1996 · Revised, October 1997, June 1998 · Accepted, July 1998 相似文献
928.
This paper treats the upscaling of the absolute permeability in a heterogeneous reservoir. By replacing the fine scale permeability tensor with an upscaled, or effective permeability tensor, a modelling error is introduced. An a posteriori error estimate on this modelling error is formulated and tested. An implementation of the theory, based on domain decomposition coupled with a hierarchical representation of the absolute permeability field, is given. As hierarchical basis functions we have chosen the Haar system, which leads to a wavelet representation of the permeability. The wavelet representation offers a natural upscaling technique which resembles the highcut filters commonly used in signal analysis. This procedure represents an adaptive upscaling method. The numerical results show that this method conserves both the dissipation and the mean velocity in the problem fairly well. The a posteriori error estimate on the modelling error coupled with domain decomposition methods constitutes a powerful modelling tool. 相似文献
929.
查明浅表部地层地质条件,对多层及高层建筑均至关重要。针对目前上海地区,在运用小螺纹钻孔进行浅表部工程勘察中存在的一些问题,就其如何合理使用,作了若干方面的探讨。 相似文献
930.