太子河本溪城区段河流水生态系统健康评价     

于英潭  王首鹏  刘琳  邢芳芳  张朝星  钟达  赵文博  王俭 《气象与环境学报》2020,36(1):89-95

太子河作为本溪的主要河流,是本溪工业、农业、生活的主要水源,为了更好的了解太子河本溪城区段的水体情况,以太子河本溪城区段流域为研究对象,基于2017年的平水期（4月）、丰水期（8月）、枯水期（11月）18个监测断面的监测数据,结合太子河本溪城区段的实际情况和特点,利用层次分析法的评价指标体系,对太子河本溪城区段进行水生态系统健康评价。通过比较分析,最终以平水期的评价结果为主,丰水期和枯水期的评价结果为辅。结果表明：仅有22%的监测断面处于健康状态、56%的监测断面处于亚健康状态、22%的监测断面处于一般状态,说明太子河本溪城区段大部分流域处于亚健康状态,水生态系统退化,需要加强管理和治理保护。  相似文献   

Prediction of Flowing Bottomhole Pressures for Two-Phase Coalbed Methane Wells     

LIU Xinfu 《《地质学报》英文版》2013,87(5):1412-1420

A method is proposed to predict the flowing bottomhole pressures(FBHPs)for two-phase coalbed methane(CBM)wells.The mathematical models for both gas column pressure and two-phase fluid column pressure were developed based on the well liquid flow equation.FBHPs during the production were predicted by considering the effect of entrained liquid on gravitational gradients.Comparison of calculated BHPs by Cullender-Smith and proposed method was also studied.The results show that the proposed algorithm gives the desired accuracy of calculating BHPs in the lowproductivity and low-pressure CBM wells.FBHP is resulted from the combined action of wellhead pressure,gas column pressure and fluid column pressure.Variation of kinetic energy term,compressibility and friction factors with depth increments and liquid holdup with velocity should be considered to simulate the real BHPs adequately.BHP is a function of depth of each column segment.The small errors of less than 1.5%between the calculated and measured values are obtained with each segment within 25 m.Adjusting BHPs can effectively increase production pressure drop,which is beneficial to CBM desorption and enhances reservoir productivity.The increment of pressure drop from 5.37 MPa2 to 8.66 MPa2 leads to an increase of CBM production from 3270 m3/d to 6700 m3/d and is attributed to a decrease in BHP from 2.25 MPa to 1.33 MPa.  相似文献   

A numerical study on the occurrence of flowing wells in the discharge area of basins due to the upward hydraulic gradient induced wellbore flow          下载免费PDF全文

Zhi‐Yuan Zhang  Xiao‐Wei Jiang  Xu‐Sheng Wang  Li Wan  Jun‐Zhi Wang 《水文研究》2018,32(11):1682-1694

The occurrence of flowing wells in basins has been found to be closely related to the discharge area with an upward hydraulic gradient. Unfortunately, previous studies on upward gradient induced wellbore flow with equaling total inflow (Q_in) in the deep and total outflow (Q_out) in the shallow could not explain the occurrence of flowing wells. By representing wells using the MNW2 Package imbedded in MODFLOW 2005, we obtain the exchange of groundwater between the aquifer and the well in the discharge area of 3D unit basins and identify three scenarios: Q_in = Q_out, Q_in > Q_out > 0 and Q_in > Q_out = 0. The relationship of Q_in > Q_out well explains why flowing wells only develop in a limited part of the discharge area. Sensitivity analysis shows that well location, water table undulation, and basin length–depth ratio do not change the profile of the ratio of cumulative flow rate in a flowing well to total inflow (Q_v/Q_in) versus the relative elevation in the inflow segment, z_in*, but could significantly change the length of the inflow segment; well depth could change both the length of the inflow segment and the profile of Q_v/Q_in versus z_in*. Based on the numerical results in homogeneous and isotropic basins with different basin length–depth ratios in the current study, the ratio of inflow in the lower half part of a flowing well to the total inflow is found to be at least 67% and could be close to 100%, indicating that water at the outlets of flowing wells with long open sections is mainly from the deep part of the well.  相似文献   

含瓦斯煤样横向变形与瓦斯流动特性耦合关系试验研究   总被引：2，自引：0，他引：2  

赵洪宝  李华华  杜秋浩  蒋军军 《岩土力学》2013,34(12):3384-3388

以二次成型煤样为研究对象,运用自行研制开发的含瓦斯煤热-流-固耦合三轴伺服渗流试验装置对含瓦斯煤样三轴加载过程中横向变形和与瓦斯流动特性的耦合关系进行了试验研究。结果表明：弹性力学定义的泊松比不能准确表征含瓦斯煤样的横纵应变特性,其关系可用二次函数表征;在预加载荷引起的横压向应变恢复阶段瓦斯流动速度变化呈先急剧降低再缓慢增加特性;在横向应变逐渐向扩张应化转变阶段,煤样内部的瓦斯流动速度呈单调缓慢增加趋势,且存在一个内部结构临界状态点使煤样内瓦斯流动速度最小;含瓦斯煤样处于横向压应变状态起始时的瓦斯流动速度要大于处于横向应变呈扩张状态末端时的瓦斯流动速度。  相似文献   

四川兴文二叠纪风暴稳流场颗粒运动的分形研究     

刘祖涵  张斌  王莉莉  税伟 《四川地质学报》2009,(Z1):64-69

颗粒是一种分形介质,其尺寸大到若干米,小到若干埃。通过颗粒系统各种密度函数的研究,可以得到微观方面—分形颗粒的粒径分布分维对系统的影响,对表征颗粒流动性具有重要意义。根据分形介质DLK反映模型的一级反映扩散方程,把布朗颗粒的运动及热力学理论推广到风暴流场,得到Γ(t)-D模型,此模型把颗粒径的分布分维和颗粒的空间坐标(或位移)、密度(或浓度)等总体微观统计特征,及经过空间某一位置的速度、粒径随时间的动态变化行为和颗粒流动的不均匀空间分布结构特征等丰富的信息为作我们研究颗粒运动提供重要的理论依据。  相似文献   

石英C轴组构指示北大别造山后伸展期中-下地壳流变形式     

向必伟  王勇生  朱光  胡召奇  谢成龙 《大地构造与成矿学》2017,41(5):801-816

造山带中-下地壳韧性流变形式反映深部岩石圈构造活动形式,是造山带深部岩石圈运动学及动力学研究的重要内容。前人对板块俯冲阶段造山带中-下地壳流动开展了较为深入的研究,但对造山后伸展期中-下地壳流变形式及其深部动力学认识不足。本次工作对北大别造山后伸展期中-下地壳岩石开展了详尽的构造观察和石英C轴组构分析,研究造山后伸展期中-下地壳流变形式。本次研究表明,中-下地壳流变带内岩石变形从边界区域的简单剪切变形为主导逐渐转变为在核部区域以纯剪切变形为主。流变带内部岩石变形特征表明北大别中-下地壳流变带的流变形式是介于活动边界条件下的透入性剪切流动和固定边界条件下韧性垮塌流动的过渡形式。这一流变形式可能是深俯冲太平洋板块的绕屈回撤和加厚造山带地壳活化韧性垮塌叠加的结果。  相似文献   

流动式CuBr激光器的设计     

马秦生  赵凤琴 《测绘信息与工程》1996,(1)

给出了流动式ＣｕＢｒ激光器的设计方法并着重讨论了放电管和缓冲气体对激光输出功率的影响。  相似文献   

浮球式海底取样器的结构及工作原理——海底取样技术介绍之四   总被引：1，自引：0，他引：1  

补家武  中国地质大学  陈汉中 《地质科技情报》2001,20(1):109-112

介绍了浮球式海底取样器的结构、性能特点、典型应用及性能参数；论述了振动式及振动冲击式贯入理论的原理；并分析了海流及船体飘移对海上取样作业的影响及解决办法。  相似文献   

南京地铁软-流塑淤泥质地层劈裂注浆试验研究   总被引：7，自引：0，他引：7  

张旭芝  符飞跃  王星华 《水文地质工程地质》2004,31(1):67-70

针对南京地铁南北线一期工程某区间隧道软—流塑地层的大管棚加小导管超前注浆预加固工程 ,对软—流塑淤泥质地层劈裂注浆加固的机理及主要影响因素进行了分析 ,对注浆效果、浆体材料及配比进行了试验研究。现场试验表明 ,采用劈裂注浆加固是可行的 ,且效果显著。  相似文献   

地下工程洞体突然涌水量的理论计算   总被引：2，自引：0，他引：2  

孙峰根  潘国营 《水文地质工程地质》1997,24(1):36-38,48

本文通过对基岩水运动的平均流速分析，提出了不同流条件突水的涌水量理论计算方法，也为现场突然涌水量计算提供了新的理论依据。  相似文献