Boundary Finite-Element Method Coupling Finite-Element Method for Steady-State Analyses of Dam-Reservoir Systems

The boundary finite-element method (BFEM) is extended for steady-state analyses of dam-reservoir system problems. In this study, the dam is assumed to be rigid and subjected to horizontal ground motions, and the liquid in the reservoir is assumed to be semiinfinite. The semiinfinite reservoir domain is partitioned into two subdomains: a near-field domain and a far-field domain. In it, the near-field domain is modeled by using the finite-element method (FEM), whereas the far-field domain is modeled by BFEM and is treated as a layered semiinfinite fluid domain. A BFEM/FEM coupling procedure is employed to solve the steady-state response of the reservoir. The coupling procedure is easy to implement and suitable for all frequencies, be it real or complex. The BFEM/FEM coupling procedure is validated in the frequency domain. Numerical results that are based on the present procedure are in good agreement with analytical and other available numerical solutions.     

Energy Dissipative Plunging Flows

The analysis of plunging flows using energy dissipation hypothesis is presented in this paper. The classic two-control-volume theory has recently been found questionable and needs to be corrected. In this study, we avoid the questionable part of that framework and use a single control volume for the analysis of plunging flows. Furthermore, we hypothesize that the increase in kinetic energy in the underflow and entrained flow should be no greater than the loss in potential energy as the inflow plunges. In the current framework, the entrained flow rate does not exceed approximately 40% of the total inflow rate. The densimetric Froude number at the plunge point, Fdp = q/, where q = inflow rate per unit width; g′ = reduced gravity of inflow; and Hp = flow depth at the plunge point, is typically in the range of 0.3相似文献   

含助剂的生物聚合物驱油剂性能研究

针对胜坨油田油层温度和地层水矿化度较高的特点，提出了含助剂的黄胞胶生物聚合物驱油剂。评价了该驱油剂的溶解性、注入性与驱油性能，考察了驱油剂溶液粘度、注入时间与驱油效果的关系。结果表明，该驱油剂有良好的溶解性和注入性，具有明显的增油降水作用，可用于较高温度的高含盐油藏。     

Radioactive Marker Measurements in Heterogeneous Reservoirs: Numerical Study

A numerical study is performed to simulate the vertical deformation of a depth interval representing a marker spacing (10.5 m) located in a deep heterogeneous sedimentary reservoir. Realistic lithostratigraphic sequences typical of the Northern Adriatic basin are used. A number of scenarios are addressed consistent with the available data. In particular two basic geologic scenarios at the marker scale are simulated, one where sands prevail within the marker spacing (SD), and another where thin sandy and clayey layers alternate (CL). The sensitivity of the marker response is investigated in relation to clay and sand permeability and compressibility contrast, Biot’s coefficient, and respective position of monitoring and fluid pumping wells. The modeling results show that rock may indeed expand above and below depleted layers. Depending on the marker position the expansion may partially offset the compaction, especially in the CL scenario with a very low permeable clay. To obtain a representative field compaction the markers should span a depth interval made mostly by sand and entirely depleted, and should be installed in a test hole far from producing wells. Compressibility contrast and the Biot coefficient play a secondary role. Very critical measurements are provided by two markers which incorporate a thin (≈1 m) depleted level overlain and underlain by almost impermeable clay layers.     

带油环底水凝析气藏开发方式优化及均衡开采对策——以东海盆地西湖坳陷CX北区块为例

东海盆地西湖坳陷CX北区块H3b、H3c油气藏为海上带油环底水凝析气藏,采用油气同采且初期优先采油的开发方式共设计了4口水平井,水平段位于油气界面以下的油环上部。为了尽快回收投资,该气藏在开发初期采用较高速度开采,油气井生产动态开始出现产量递减加快、气油比快速上升、含水率快速上升等现象,表明气顶和油环开采出现不均衡状态,而且位于油环下部的井已开始出现底水锥进。为此,基于该区块油气藏地层油气流体相态特征,同时结合油气井生产动态特征,分析反凝析、气顶气下窜、底水上升锥进等因素对该油气藏开发动态的影响,进而提出对策:(1)利用气顶气和油环油溶解气的弹性能量以及边底水天然水驱方式来开采油气藏,并合理控制采油采气速度,尽可能地实现油气藏的均衡开采;(2)由于过早打破了油气井的均衡开采状态,导致了气顶气过早下窜和边底水过早侵入,需要通过实时调整采油气速度来平衡开采状态,从而使得油气藏气油比和含水率得到有效控制。实施结果表明:上述对策的成功应用,确保了凝析气藏进入了稳定均衡的开发状态。     

非离子表面活性剂NS在文明寨油砂和岩心上的吸附

针对高温、高矿化度、高钙镁含量的中原文明寨油田，筛选出了非离子表面活性剂ＮＳ体系作为驱油剂。本文报道了ＮＳ在文明寨油藏油砂和岩心上的静、动态吸附实验结果。     

Modeling Salt Water Intrusion in Tanshui River Estuarine System—Case-Study Contrasting Now and Then

A vertical (laterally integrated) two-dimensional numerical model was applied to study the salt water intrusion in the Tanshui River estuarine system, Taiwan. The river system has experienced dramatic changes in the past half century because of human intervention. The construction of two reservoirs and water diversion in the upper reaches of the river system significantly reduces the freshwater inflow. The land subsidence within the Taipei basin and the enlargement of the river constriction at Kuan-Du have lowered the river bed. Both changes have contributed farther to the intrusion of tidal flow and salt water in the upstream direction. The model was reverified with the earliest available hydrographic data measured in 1977. The overall performance of the model is in reasonable agreement with the field data. The model was then used to investigate the change in salt water intrusion as a result of reservoir construction and bathymetric changes in the river system. The model simulation study reveals that significant salinity increases have resulted from the combined changes. It has been speculated by ecological researchers that the long-term increase in salinity might be the driving force altering the aquatic ecosystem structure in the lower reach of the estuary and the Kuan-Du mangrove swamp, particularly the enlargement of the mangrove area and the disappearance of freshwater marshes. However, concrete proof has not been available since no prototype salinity data were available prior to the reservoir construction. This case study offers the first quantitative estimate of the salinity changes due to human interference in this natural system.     

指"东"针以北京西苑娱乐综合项目为例

文章以北京西苑娱乐综合体的设计竞赛方案为例,分析了建筑师马库斯和马里昂“模拟”、“关联”中国建筑艺术的元素、美学的设计动机,以及转向东方的目光。     

柴达木盆地西部北区N2^1～N2^2低渗非常规储层应力敏感特征分析

通过室内实验对柴达木盆地西部北区储层岩石的应力敏感性进行了研究。结果表明,岩石类型对该区储层应力敏感性具有重要的影响,风暴岩应力敏感性一般为中偏弱,而灰泥岩储层具强的应力敏感性。风暴岩的渗透率恢复率明显高于灰泥岩的渗透率恢复率。