示踪试验在复杂岩溶区工程中的应用

以滇中引水工程某深埋长隧洞为依托,在较深入了解研究区水文地质及工程地质条件的基础上,选取线路对地下水环境影响较大的区域进行示踪试验,通过试验不仅较清晰地查清了地下水运移通道,而且较为准确地查明了研究区地下分水岭,最终为线路的选择提供了合理、准确、可行的依据。     

MOTION OF TRACER PARTICLES IN A CENTRIFUGAL PUMP AND ITS TRACKING CHARACTERISTICS

The Basset-Boussinesq-Oseen (BBO) equation can be used for most flows to trace the motion of a particle, but in a centrifugal pump, among the forces that act on the particles, one should also include those due to the impeller rotation, as additional effects. This paper firstly reviews various approximations of the BBO equation for the motion of dispersion particles in a viscous fluid. Then based on the motion equation for particles in low Reynolds number centrifugal pumps, a formula for calculating the tracking characteristics of tracer particles is deduced through the Fourier integral transformation. After that the deviations of the particle motion from the fluid motion, as predicted by the various approximations, are discussed and compared. At last, with an emphasis on the Particle Image Velocimetry (PIV) results, the tracking characteristics of particles are estimated. Also, advantages and disadvantages of different tracer particles are discussed and suitable tracer particles for application in PIV studies for flow fields in centrifugal pumps are suggested.     

井间示踪剂技术在油田开发中的应用

介绍了油田开发中几种常用的井间示踪剂技术原理、特点及在油田的应用效果和发展趋势,阐述了井间示踪剂技术的多种用途。通过示踪剂技术可以分析油田的水驱规律,了解断层的封闭状况,验证油水井的连通情况,计算注水井在平面上各个方向的渗流速度以及油井的水淹方向,确定区块的剩余油分布等,对于进一步认识油藏的非均质性、注入水沿裂缝窜流的规律、注水方案调整以及调剖堵剂用量的确定起到了积极的指导作用,为油田的油水井调整、工艺技术措施和综合治理提供了可靠的科学依据。     

孔中同位素示踪方法研究裂隙岩体渗流

本文推导了孔中测定岩体裂隙渗透流速、等效力学隙宽的稀释定理及双井混合井流理论，通过对裂隙的渗透流速、流向、吸水量或涌水量等参数的测定，结合裂隙渗流立方定理与稳定流理论，提出了一种确定岩体裂隙渗透系数的示踪方法。     

一种新型的微颗粒示踪剂及其在致密油藏中的应用

目前应用于油气田的示踪剂为水溶性示踪剂或者是气体示踪剂.经过多年的研究,开发了一种新类型的微颗粒固体示踪剂,并在长庆油田致密油藏中成功施工,标志着从实验成功走向了矿场.固体示踪剂在油气田开发中的应用前景广阔,尤其对致密油藏井间裂缝开度的定量描述具有指导意义.     

基于EFDC示踪模拟的人工湖调水规模分析

城市景观人工湖规划设计时,需在湖体水质恶化到一定程度引入新的水体进行调水置换,以确保湖区水环境质量,合理确定的引水条件将有效节约引水资源量。以石家庄市正定湖为例,基于EFDC水环境数学模型,分析了不同调水方案下湖区示踪粒子追踪模拟情况,根据示踪粒子追踪模拟结果,确定了湖区最优调水规模,并探明了湖区潜在的重污染区域和富营养化高发区,为切实保障湖区水环境质量提供了技术参考。     

黄河多泥沙河段扩散系数的示踪实验研究

扩散系数的确定是河流水质模拟与预测的一项重要内容。为确定黄河多泥沙河段横向混合系数和纵向离散系数,在黄河孟津段进行了现场扩散示踪实验。实验选择不被泥沙吸附、在黄河本底浓度值低、测定方法成熟的重铬酸钠作为示踪剂,示踪剂采用岸边有限时段恒速连续方式投放。示踪剂在混合区的混合输移规律用稳态二维Taylor扩散方程定量描述,扩散方程中的扩散系数用有限差分法求解。根据示踪实验获得的实测数据,计算求得横向混合系数值为0．32m^2／s、纵向离散系数值为40m^2／s。用求得的扩散系数值进行示踪剂扩散输移模拟计算,其模拟计算值与实测值相比较的最大相对误差为27．2％。结果表明本次示踪实验是成功的,由示踪实验确定的扩散系数值是可靠的。考虑本河段水力学情况,选择式E=αHu,作为由水力学参数直接推导扩散系数的经验公式,并且根据示踪实验的实测数据进行计算,得到实验河段的无因次横向混合系数αx值为3．61、无因次纵向离散系数αx值为451．25。     

Driving factors of the flushing time of bays formed where tributaries enter a reservoir

Flushing time is an integrative parameter that can represent water exchange capacity and sensitivity to pollution threats. As bays formed where tributaries enter the Three Gorges Reservoir of China have experienced frequent algal blooms over the past decade, we examine the spatially variable flushing time of a typical tributary bay (Xiangxi Bay) by numerical tracer experiments. First, the tracer concentration reduction could be approximated well by a double exponential decay curve, and the local flushing time of Xiangxi Bay is determined using key flushing coefficients. Second, a sensitivity analysis is performed to examine the influence of upstream inflow, temperature difference, wind, water level of the reservoir, and daily water level fluctuation on the spatial variation in local flushing time. Finally, according to local flushing time values and the sensitivity analysis results, the bay can be generally characterized by three zones: riverine, transitional, and mainstream‐influenced zones. In particular, the local flushing times in the riverine zone are mainly affected by the upstream inflow. The difference in temperature between the reservoir mainstream and Xiangxi Bay is the main forcing in the transitional and mainstream‐influenced zones. This study is the first to investigate different driving factors for flushing time in a typical reservoir tributary bay. The findings provide insights on the transport processes in such water bodies, suggesting the possibility of using the longitudinal zonation of flushing time for reservoir management.     

综合检测技术在面板堆石坝渗漏检测中的应用

经过30多年发展,我国面板堆石坝建设成就显著,但同时也面临着诸如大坝渗漏等病害问题。面板堆石坝坝体材料的非同质和变形的多维度,使得大坝渗漏形式多样,给大坝渗漏检测带来巨大挑战。为此,针对新疆某面板坝,首先应用资料分析和水下机器人声纳扫描普查确定可能渗漏的区域,然后派潜水员进行水下高清摄像详查破损区,最后采用示踪剂进行连通试验验证此前判断。上述综合检测技术在该面板堆石坝渗漏检测中得到成功应用,相关经验可供类似面板坝渗漏处理参考。     

A simple low-cost approach for transport parameter determination in mountain rivers

A simplified low-cost approach to experimentally determine transport parameters in mountain rivers is described, with an emphasis on the longitudinal dispersion coefficient (D_L). The approach is based on a slug injection of table salt (NaCl) as a tracer and specific conductance readings at different locations downstream of the injection spot. Observed specific conductance readings are fit using the advection-dispersion equation with OTIS-P, yielding estimates of cross-sectional area and longitudinal dispersion coefficient for various stream reaches. Estimates of the D_L are used to assess the accuracy of several empirical equations reported in the literature. This allowed the determination of complementary transport parameters related to transient storage zones. The empirical equations yielded rather high D_L values, with some reaching up an order of magnitude higher to those obtained from tracer additions and OTIS-P. Overall, the proposed approach seems reliable and pertinent for river reaches of ca. 150 m in length.