共查询到19条相似文献，搜索用时 125 毫秒
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重庆大足井水位对邻井抽水的奇异响应及其机理 总被引：1，自引：0，他引：1
大足井位于重庆市大足县拾万镇,井深108.7m,观测含水层为J2S泥岩夹砂层的风化裂隙潜水层。多年的观测结果表明,每当相距仅14.6m的邻井抽水时,该井水位不仅不降,反而上升,是国内外罕见的奇异现象。通过对这一现象进行的观测资料分析、井区地质-水文地质条件调查、现场试验观测及理论分析等得出,大足井水位对邻井抽水的奇异响应是在特定的水文地质条件下,抽水降落漏斗外边界带上因水流速度较大引起的动水压力使该处的观测井产生的特殊井水位动态。 相似文献
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永安冷冻厂深井是东南沿海最深的地震地下水动态观测井,井深1 000.44 m,地下水位受邻孔抽水严重影响.1982年1月开始观测,1988年11月起塑料厂开始抽水,严重影响观测;2001年8月由于工厂停产停止抽水,观测井地下水动态逐渐趋于稳定.本文分析该井地下水动态年变化规律,计算水位固体潮潮汐因子、观测精度与井孔对地应力响应灵敏度.并对抽水干扰及其前后,地下水动态观测质量的变化进行对比. 相似文献
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一、水动态变化对氡值的影响为了研究水氡观测中存在的某些干扰因素,就本地的水文地质条件,我们选择了某单位作为生产用水的一组深井群中的12号井作为观测井如图1—1。该井群由一周管道联通,各井由潜水泵连续不停抽水。从图1—2可以看到,12号抽水井深50 相似文献
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怀来地震台伸缩仪观测曲线年变形态每年出现2次较大幅度的阶跃型上升,且变化幅度大小不同。对该地震台观测山洞周边4 km范围内抽水井的分布、2016-2017年季节性抽水时间、抽水量、群井开抽数量等进行调查,并与伸缩仪观测曲线异常变化进行对比分析,发现在时间及变化幅度上,二者同步性较好,分析认为形变观测的周期性大幅度上升变化应与观测山洞周边群井抽水有关,非地震前兆异常变化;并对抽水引起的形变观测机理进行初步分析,提出干扰消除方法。 相似文献
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观测井中氦含量异常与地震关系的研究 总被引：2，自引：1，他引：2
阐述了黑龙江省林甸观测井、山东省聊城聊古一井和云南省开远观测井观测到的氦含量变化与周围发生的中强地震的关系.由于氦的物理化学的特性,它在地震前能灵敏地反映出地震的前兆变化,氦的异常幅度与震级成正相关,与震中距成负相关,异常一般都是在地震前15～30 d左右.根据观测井所处的构造条件和氦来源深度的不同,观测到氦含量的异常变化不一致性,有正异常,也有负异常变化,这与孕震应力场作用导致气体来源途径的不同有关.地热异常区的高温井逸出气和逸出气中以天然气为主的观测井氦气测值高,低温井逸出气的氦气测值低.人可明显感觉到有气体流出的观测井,其交换速度快,氦气异常呈现出突变型特征;而低温静水位观测井,其气体流量小的观测井,交换速度慢,其氦气异常呈现出缓变型的特征. 相似文献
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栾城王家庄井水位异常分析 总被引：1，自引：1，他引：0
2012年8月栾城王家庄井水位短时间内多次出现快速、大幅下降变化,调研发现,下降异常由距离该井约860 m的新井抽水引起.利用抽水试验模型,定量模拟抽水对王家庄井水位的变化影响,模拟结果与实际变化量相当,进一步确定该井水位下降异常为抽水影响. 相似文献
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Angeliki Aisopou Philip J. Binning Hans‐Jørgen Albrechtsen Poul L. Bjerg 《Ground water》2015,53(5):722-736
This study examines the effect of pumping, hydrogeology, and pesticide characteristics on pesticide concentrations in production wells using a reactive transport model in two conceptual hydrogeologic systems; a layered aquifer with and without a stream present. The pumping rate can significantly affect the pesticide breakthrough time and maximum concentration at the well. The effect of the pumping rate on the pesticide concentration depends on the hydrogeology of the aquifer; in a layered aquifer, a high pumping rate resulted in a considerably different breakthrough than a low pumping rate, while in an aquifer with a stream the effect of the pumping rate was insignificant. Pesticide application history and properties have also a great impact on the effect of the pumping rate on the concentration at the well. The findings of the study show that variable pumping rates can generate temporal variability in the concentration at the well, which helps understanding the results of groundwater monitoring programs. The results are used to provide guidance on the design of pumping and regulatory changes for the long‐term supply of safe groundwater. The fate of selected pesticides is examined, for example, if the application of bentazone in a region with a layered aquifer stops today, the concentration at the well can continue to increase for 20 years if a low pumping rate is applied. This study concludes that because of the rapid response of the pesticide concentration at the drinking water well due to changes in pumping, wellhead management is important for managing pesticide concentrations. 相似文献
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Nikolaos Nagkoulis 《Ground water》2021,59(3):410-416
This paper deals with water pumping cost minimization, in a confined infinite aquifer, proposing an alternate pulsed pumping schedule. The transient flow analysis is conducted for two wells with equal pumping rates. Specifically, two pumping schedules are analytically compared. In the first case, well users pump simultaneously, and in the second one they cooperate so that they pump alternately. This paper proves that the proposed alternate pumping schedule works as a stabilizer, reducing the high hydraulic drawdowns values, regardless of the aquifer characteristics. Moreover, pumping alternately is better in terms of pumping cost, compared to simultaneous pumping, though benefit become negligible as distance between wells becomes large. Two simplified equations are proposed, one to find the difference of the hydraulic drawdowns between the two pumping schedules and the other one to find the economic benefit of each well from cooperation. The equations are finally applied to a number of cases and their results are compared to the results obtained from an algorithm created to calculate the hydraulic drawdowns and the pumping cost, using the Theis equation. The results can be very useful in irrigation scheduling, as they can be applied to systems of well users/farmers, to reduce pumping cost. 相似文献
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V. S. SINGH 《水文科学杂志》2013,58(4):589-594
Abstract Well storage effect is generally considered while interpreting pumping test data from large diameter wells. However, in an aquifer of low permeability, the well storage is found to be significant during pumping tests conducted on bore wells. The interpretation of such data gives ambiguous results unless well storage effect is taken into account. A field example is presented to illustrate the difficulty in interpretation of the pumping test data. In order to take into account the well storage effect, a finite difference approach of interpreting pumping test data is suggested. 相似文献
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In confined aquifers, the influence of neighboring active wells is often neglected when interpreting a pumping test. This can, however, lead to an erroneous interpretation of the pumping test data. This paper presents simple methods to evaluate the transmissivity (T) and storativity (S) of a confined aquifer under Theis conditions, when an interfering well starts pumping in the neighborhood of the tested well before the beginning of the test. These new methods yield better estimates of the T and especially S values than when the interfering well influence is neglected. They also permit to distinguish between interfering wells and other deviations from the Cooper‐Jacob straight line, such as impermeable boundaries. The new methods were then applied on data obtained from a numerical model. The new methods require knowing the pumping rate of the interfering well and the time elapsed since the pumping started in each well, but contrary to previous methods, they do not require the aquifer natural level at the beginning of the test, which is often unknown if the interfering well has started pumping before the tested well. 相似文献
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Ferenc Székely 《Ground water》2013,51(5):762-767
The vertical variation of drawdown around pumping wells generates an induced flow in the observation wells. A set of governing equations is presented to couple the drawdown variation and the vertical flux distribution in observation wells. A numerical example is performed to justify the governing equations and to verify the solution methods used by the simulation software WT. The example analyzes the effect of skin loss, wellbore storage, and vertical segmentation on the drawdown and induced flow in observation well during pumping. The evaluation of the Fairborn pumping test involves a vertically homogeneous and anisotropic water table aquifer, uniform well‐face drawdown conditions in the pumping well and simulation of the drawdown evolution in the observation well with and without the effect of induced flow. The computer calibrations resulted in small differences between the measured and simulated drawdown curves. 相似文献
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We developed a method to estimate aquifer transmissivity from the hydraulic-head data associated with the normal cyclic operation of a water supply well thus avoiding the need for interrupting the water supply associated with a traditional aquifer test. The method is based on an analytical solution that relates the aquifer's transmissivity to the standard deviation of the hydraulic-head fluctuations in one or more observation wells that are due to the periodic pumping of the production well. We analyzed the resulting analytical solution and demonstrated that when the observation wells are located near the pumping well, the solution has a simple, Dupuit like form. Numerical analysis demonstrates that the analytical solution can also be used for a quasi-periodic pumping of the supply well. Simulation of cyclic pumping in a statistically heterogeneous medium confirms that the method is suitable for analyzing the transmissivity of weakly or moderately heterogeneous aquifers. If only one observation well is available, and the shift in the phase of hydraulic-head oscillations between the pumping well and the observation well is not identifiable. Prior knowledge of aquifer's hydraulic diffusivity is required to obtain the value of the aquifer transmissivity. 相似文献
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INFLUENCE OF PUMPING ON FOUR-COMPONENT BOREHOLE STRAIN AT TAI'AN SEISMIC STATION AND ITS INTERFERENCE MECHANISM 
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下载免费PDF全文 JIA Yuan GAN Wei-jun LI Jie ZHU Cheng-lin YIN Hai-tao LU Shuang-ling JU Jia-bin 《地震地质》2019,41(6):1429-1443
Four-component borehole strainmeter (FCBS) is one kind of high-precision borehole strain observation instruments invented in China. As a kind of near-surface deformation observation instrument, FCBS is also easily disturbed by the external environment factors. As a common factor, pumping has significant influence on FCBS observation. Existing studies mostly identify the pumping interference from the perspective of observation curve morphology, relatively few studies focus on its interference mechanism. In order to truly capture earthquake precursor information, it is necessary to study the interference mechanism. In recent years, RZB-3 type FCBS at Tai'an seismic station has been seriously affected by pumping, so it is necessary and also feasible to study the interference mechanism of pumping. Since the influence of pumping interference on borehole strainmeter is common, this work would be very practical and be used for reference by other borehole strain observation stations.
We find that the original observation curves and observed surface strain, shear strain from RZB-3 type FCBS at Tai'an seismic station have the characteristics of synchronous change with the borehole water level, in which the linear correlation coefficient between the two observed shear strain curves and borehole water level reached 0.70 and 0.82 respectively. We further find that the principal strain direction of borehole and borehole water level after normalization meet the nonlinear function as y=1.217arctan(x)0.224-0.284. The above phenomenon indicates that the observation of RZB-3 type FCBS at Tai'an seismic station is significantly affected by the borehole water level, and the influence is more obvious and the gradient is larger at the stage of low water level. Pumping interference often appears in low water level stage and changes the rock pore pressure state. Statistics show that pumping interference affects the borehole strain state.
To investigate the interference mechanism of pumping to RZB-3 type FCBS at Tai'an seismic station, we take a known pumping as an example, in which we study the principal strain state of the borehole in three periods of normal pumping, interruption of pumping and resuming pumping respectively. During each period, we solve 3 parameters of the principal plane strain state, i.e. the maximum principal strain rate, the minimum principal strain rate and the maximum principal strain direction from four observation equations of FCBS by nonlinear iterative least squares algorithm. On the other hand, concentrated load model (CLM) is used to simulate the mechanical mechanism of pumping. Firstly, the depth of FCBS relative to pumping source and the concentrated load at pumping source are inversed, then, the strain state surrounding the pumping well, including the state at RZB-3 borehole, is simulated by forward modeling. By comparing these results, we find that:
(1)The concentrated load at pumping source inversed by CLM during periods of normal pumping and resuming pumping are both located at or near the bottom of the pumping well, which is consistent with the actual situation, indicating that mechanism and degree of the influence of pumping on borehole strain are well simulated by CLM.
(2)The observed strain state is consistent with the simulation result of pumping interference by forward modeling, indicating that the principal strain state of borehole calculated based on observation of FCBS reflects the true strain state of borehole under different pumping states.(3)The inversed concentrated load at pumping source during pumping periods is significant greater than the load of the pumped water, indicating that the pumping process has more significant influence on the pore pressure of rocks than the load of the pumped water.
Even though CLM is an approximate simulation since it's based on some elastic assumptions, the interference mechanism of pumping on RZB-3 type FCBS at Tai'an seismic station is well explained, which is maybe very helpful for studying the influence of pumping interference on other deformation instruments, locating the unknown pumping source and studying the characteristics of pore pressure of rocks. 相似文献
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《Advances in water resources》1999,22(6):623-632
In a phreatic aquifer, fresh water is withdrawn by pumping from a recovery well. As is the case here, the interfacial surface (air/water) is typically assumed to be a sharp boundary between the regions occupied by each fluid. The pumping efficiency depends on the method by which the fluid is withdrawn. We consider the efficiency of both continuous and pulsed pumping. The maximum steady pumping rate, above which the undesired fluid will break through into the well, is defined as critical pumping rate. This critical rate can be determined analytically using an existing solution based on the hodograph method, while a Boundary Element Method is applied to examine a high flow rate, pulsed pumping strategy in an attempt to achieve more rapid withdrawal. A modified kinematic interface condition, which incorporates the effect of capillarity, is used to simulate the fluid response of pumping. It is found that capillarity influences significantly the relationship between the pumping frequency and the fluid response. A Hele-Shaw model is set up for experimental verification of the analytical and numerical solutions in steady and unsteady cases for pumping of a phreatic aquifer. When capillarity is included in the numerical model, close agreement is found in the computed and observed phreatic surfaces. The same model without capillarity predicts the magnitude of the free surface fluctuation induced by the pulsed pumping, although the phase of the fluctuation is incorrect. 相似文献