开采条件下多时段水量均衡法的应用研究

根据大武水源地多年大强度持续超采呈现出来的岩溶水的补、迳、蓄、排特征和水位、水量长期监测资料,在传统水均衡法的基础上提出了开采条件下多时段水量均衡法,并将其应用于大武水源地的可采量计算中。最后,依据评价结果建立了不同开采条件下大武水源地可采量预测模型。     

Three‐dimensional transient thermo‐hydro‐mechanical fundamental solutions of unsaturated soils

The governing differential equations of unsaturated soils considering the thermo‐poro‐mechanical behaviour consist of equilibrium, moisture air and heat transfer equations. In this paper at first, following some necessary simplifications, the thermal three‐dimensional fundamental solution for an unsaturated deformable porous medium with linear elastic behaviour in Laplace transform domain is presented. Subsequently, the closed‐form time domain fundamental solutions are derived by analytical inversion of the Laplace transform domain solutions. Then a set of numerical results are presented, which demonstrate the accuracies and some salient features of the derived analytical transient fundamental solutions. Finally, the closed‐form time domain fundamental solution will be verified mathematically by comparison with the previously introduced corresponding fundamental solution. Copyright © 2009 John Wiley & Sons, Ltd.     

Thermal reservoir modeling in petroleum geomechanics

Thermal oil recovery processes involve high pressures and temperatures, leading to large volume changes and induced stresses. These cannot be handled by traditional reservoir simulation because it does not consider coupled geomechanics effects. In this paper we present a fully coupled, thermal half‐space model using a hybrid DDFEM method. A finite element method (FEM) solution is adopted for the reservoir and the surrounding thermally affected zone, and a displacement discontinuity method is used for the surrounding elastic, non‐thermal zone. This approach analyzes stress, pressure, temperature and volume change in the reservoir; it also provides stresses and displacements around the reservoir (including transient ground surface movements) in a natural manner without introducing extra spatial discretization outside the FEM zone. To overcome spurious spatial temperature oscillations in the convection‐dominated thermal advection–diffusion problem, we place the transient problem into an advection–diffusion–reaction problem framework, which is then efficiently addressed by a stabilized finite element approach, the subgrid‐scale/gradient subgrid‐scale method. Copyright © 2008 John Wiley & Sons, Ltd.     

Solid–liquid–air coupling in multiphase porous media

This paper addresses various issues concerning the modelling of solid–liquid–air coupling in multiphase porous media with an application to unsaturated soils. General considerations based on thermodynamics permit the derivation and discussion of the general form of field equations; two cases are considered: a three phase porous material with solid, liquid and gas, and a two phase porous material with solid, liquid and empty space. Emphasis is placed on the presentation of differences in the formulation and on the role of the gas phase. The finite element method is used for the discrete approximation of the partial differential equations governing the problem. The two formulations are then analysed with respect to a documented drainage experiment carried out by the authors. The merits and shortcomings of the two approaches are shown. Copyright © 2003 John Wiley & Sons, Ltd.     

Decoupling and Block Preconditioning for Sedimentary Basin Simulations

The simulation of sedimentary basins aims at reconstructing its historical evolution in order to provide quantitative predictions about phenomena leading to hydrocarbon accumulations. The kernel of this simulation is the numerical solution of a complex system of partial differential equations of mixed parabolic–hyperbolic type. A discretisation and linearisation of this system leads to large ill-conditioned nonsymmetric linear systems with three unknowns per mesh element. The preconditioning which we will present for these systems consists in three stages: (i) a local decoupling of the equations which (in addition) aims at concentrating the elliptic part of the system in the “pressure block”; (ii) an efficient preconditioning of the pressure block using AMG; (iii) the “recoupling” of the equations. In all our numerical tests on real case studies we observed a reduction of the CPU-time for the linear solver (up to a factor 4.3 with respect to the current preconditioner ILU(0)) and almost no degradation with respect to physical and numerical parameters. This revised version was published online in July 2006 with corrections to the Cover Date.     

Forward and Inverse Problems in Modeling of Multiphase Flow and Transport Through Porous Media

The paper deals with numerical simulation techniques for forward and inverse modelling in multiphase (multicomponent) flow through porous media. The forward simulation software system MUFTE-UG uses recent discretization techniques and fast solvers. The efficient integration of optimization strategies for the solution of the inverse problems is demonstrated in detail and also applied to practical numerical examples.     

叠加断裂及其分类

阐述了叠加断裂的概念，并按各期断裂活动的位置与强度、构造层次对其进行了分类。     

Petroleum Exploration of Craton Basins in China

1 Introduction The craton is a relatively stable continent block which is covered by thick sediments forming significant petroliferous basins and groups of great oil and gas fields. Ivanhoe et al. (early 1990’s) indicated that about half of the 509 large oil and gas fields in the world were related to craton basins (Ivannoe and Leckie, 1993). Mann et al. (2001) suggested that 54.7% of the 592 large fields were developed in the cratonic sag basins and about 30% located in the rifts and depres…     

Eulerian-Lagrangian formulation of the equations for groundwater denitrification using bacterial activity

A mathematical model for groundwater denitrification using bacterial activity is presented. The model includes the momentum and mass balance equations for water and nitrogen, substrate and bacteria, and chemical reactions between them. The resulting multiphase, multicomponent, flow and transport governing equations, are coupled and nonlinear. A Eulerian-Lagrangian formulation of the equations is developed. The water and gas flow and transport equations are split into forward advection along characteristics, and a residual at a fixed frame of reference. Discontinuities, sharp fronts and steep gradients of the dependent variables are imposed on the advection mode and solved exactly. It is believed that this novel method will avoid numerical artifacts for the solution of the multiphase flow equations (e.g., upstream permeability) and numerical dispersion for the transport equation.     

多相滤波器在跳频解调中的应用

本文针对全数字多载波跳频接收机提出一种高效的解调算法,首先,跳频技术因其具有良好的抗干扰性能,在军事通信中有着广泛的应用,本文在跳频接收机下采样的处理中,添加一组下采样滤波器组,用于跳频信号的解调,该算法较于以往的算法,复杂度较低,便于实现;且该算法采用的是并行捕获,可以实现信号的快速捕获,降低同步时间;解调后,第二组滤波器组用于实现MFSK调制信号的非相关解调,进一步降低解调端的复杂度。