滇21井水位微动态特征研究

本文通过对滇２１井的地质构造部位、水文地质条件、井孔结构等方面的论述,应用该井水位观测结果,以地下水微动态理论为指导,分析了气压、固体潮、降雨等干扰因素对水位的影响,归纳出该井水位正常动态特征,探讨了识别震兆异常的方法,为综合分析多井水位异常打下了基础。     

昌黎井水位破年变异常分析

井水位破年变异常是中强震前中短期异常的重要表现形式,但降雨、地下水开采等因素也会引起水位年变动态的改变。本文利用动态年周期方法识别出2000~2013年昌黎井水位破年变异常,结果显示,2010、2012年该井水位破年变是与地震活动有关的前兆异常,其他时段的水位破年变异常多为降雨、井孔条件改变、附近井孔抽水等因素引起,表明该井水位异常可以为震情判定提供依据。     

单井水位地震异常信息的提取与地震预报

地下水位动态变化是受影响因素制约的。对于地下水动态按其主要影响因素及其动态特征可以划分出不同动态类型。本文以受抽水、降雨、固体潮、气压影响的雄101深井为例,采用别尔采夫滤波和二元回归数学方法,排除干扰,提取异常,进行地震预报,并实现了这一过程的计算机程式化。     

太平庄观测井地下流体动态综合研究

太平庄观测井是一口有十几年观测资料并有几次较好震例的综合观测井。近年来 ,由于地下水的大量开采 ,使得地下水位大幅度下降 ,尤其是观测井周围地热的开采 ,对太平庄观测井的正常动态影响较大。文中结合往年较正常的动态特征和地质构造等 ,分析了太平庄观测井的水位、水温、逸出气和断层气等的年动态变化特征。结果表明 :水位、水温的变化规律受观测井水位补给区降雨量的影响 ,水温还受当地降雨量的影响 ,特别是太平庄观测井周围新井的抽水对水温、水位、逸出气均有一定影响。由于观测井受诸多因素的影响 ,导致太平庄观测井的观测资料不能按往年的变化规律进行动态分析。在排除了降雨和人为的干扰因素外 ,太平庄观测井的资料动态趋势还可用于首都圈的震情预测     

四川盐源干海双井水位观测干扰分析

依据观测日志、降雨、水温监测和周边调查,对四川盐源干海双井水位观测干扰事件进行了详细的分类,按分类统计了干海井和干海机井干扰特征,以更加准确有效地识别与排除干扰。针对发生最为频繁的且对正常观测影响最大的堵塞和人为清洗干扰提出了初步技术解决方案。氢氧同位素分析结果表明双井井水受大气降雨补给,可通过收集降雨、河水资料来识别降雨干扰。     

太平庄井地下流体动态主要干扰因素研究

通过分析多年的观测资料，认为太平庄井地下流体动态的主要干扰因素为区域地下热水开采，其次为降雨。气压的明显变化对水位、水温也有一定干扰。区域开采造成太平庄井水位、水温同步下降，氢气测值升高；降雨导致太平庄井水位上升、水温下降。     

山西大同镇川井水位各类异常特征与成因分析

对观测环境、观测仪器、地震等各类因素在镇川井水位动态中所表现出的特征进行系统地分析与研究。根据地下水干扰异常识别与排除的原则,探讨了2007年至2012年镇川井水位出现各类异常的成因,并对研究时段的异常进行分类。研究结果表明,影响镇川井水位动态变化的主要因素有仪器故障、通讯故障、电源干扰、检修线路、维修仪器、泄流口排水管堵塞、雷电干扰、供电故障以及同震阶跃等,异常形态主要有阶跃、突变和脉冲等。     

云南姚安井2009年10月后水位下降的成因分析

地下水动态的异常变化既有可能是地震前兆异常信息, 也有可能是某种环境干扰所引起, 如降雨和地下水开采等. 如何及时识别并排除环境干扰, 对于成功判定地震前兆异常至关重要. 云南姚安井水位于2009年10月后出现了下降趋势的异常变化, 截止2011年底, 最大下降幅度达3 m. 为分析该井水位异常变化的形成原因, 依据姚安井水文地质环境特征, 建立了相关的数学物理模型, 定量分析了降水量和地下水开采量对该井水位的影响. 分析结果表明, 姚安井2009年后出现的水位大幅下降可能与区域降水量减小导致的地下水开采活动增强有一定的相关性. 文中所采取的异常识别与分析方法, 对今后地下水动态异常识别及前兆信息判定工作具有一定的借鉴意义.      

云南姚安井2009年10月后水位下降的成因分析

地下水动态的异常变化既有可能是地震前兆异常信息,也有可能是某种环境干扰所引起,如降雨和地下水开采等.如何及时识别并排除环境干扰,对于成功判定地震前兆异常至关重要.云南姚安井水位于2009年10月后出现了下降趋势的异常变化,截止2011年底,最大下降幅度达3m.为分析该井水位异常变化的形成原因,依据姚安井水文地质环境特征,建立了相关的数学物理模型,定量分析了降水量和地下水开采量对该井水位的影响.分析结果表明,姚安井2009年后出现的水位大幅下降可能与区域降水量减小导致的地下水开采活动增强有一定的相关性.文中所采取的异常识别与分析方法,对今后地下水动态异常识别及前兆信息判定工作具有一定的借鉴意义.     

太原井水位微动态信息响应能力分析

根据太原井水位趋势变化特征对研究时段进行划分,计算出各时段井水位的气压系数、潮汐因子、降雨效应及记震能力,得出不同时段井水位记录微动态信息的能力并进行相应分析。     

福建永安井水位大幅度异常变化原因的研究

2001年7月18日起,永安井水位出现持续的大幅度上升变化。经调查落实,这是由于该井附近的另一口多年开采的井孔,于2001年7月17日突然停止抽水,从而使永安井的地下水补给量增大,造成水位大幅度上升。深入分析该井水位变化的成因,为研究邻井抽水对地震地下水动态观测井水位动态的影响提供了一个实例,对于识别地下水前兆异常与抽水干扰有一定的参考意义。     

识别地下水超采区井水位异常性质的理论与方法

长期过量开采地下水,使地下水位持续下降、水质发生变化,动水位观测井断流;地面沉降造成井管上窜,观测管路系统被损坏等,这些现象对地震地下流体观测地震前兆异常的正确判断带来很大困难。应用水文地质理论与方法,分析含水层的水均衡状态、应力-应变状态及其与水位动态的关系,初步探讨了超采区井水位异常性质的理论与方法。结果表明,根据井孔所在区水位下降漏斗的扩散特征,结合以上所提到的理论和方法,依据资料多年变化特征,可以较准确地判断异常的性质。研究结果有助于区分单一集中抽水与长期地下水超采对水位观测的影响,有助于正确识别超采区水位前兆异常,有助于地震分析预报水平的提高     

天津王4井抽水观测水汞影响因素的探讨

王4井因受井区地热开发的影响,于2008年12月断流停测。2010年对原观测井口装置进行改造,开始进行抽水观测水汞试验研究。在新的观测方式下,为确保观测数据稳定、可靠,本文从抽水观测的观测条件方面,对不同取样位置和抽水时间对水汞测值的影响进行了试验。试验结果表明,不同抽水时间和不同取样位置抽水观测对水汞测值影响不大,这一结论与水汞本身的化学特性相一致。认为在没有自流井的地区,只要选择灵敏的观测点使用抽水方式采样,固定观测条件,依然可以进行水汞监测。     

高温腐蚀性抽水控制系统在怀4井的应用

由于近年来水位普遍降低以及地热资源的不断开发,造成河北怀4井水位严重下降,几近断流。为了延长该井的观测年限,2007年怀4井进行了降低取水口的改造。由于改造后出水口低于地面,必须将泄流出的水抽走,由此必须抽水进行控制。由于怀4井水温达到85℃以上,并且富含矿物质,对金属具有强腐蚀性,因此对排水控制系统提出了很高的要求。通过在怀4井的实践,给出了一种在高温和腐蚀性等条件下长期正常运行的抽水控制系统。     

INFLUENCE OF PUMPING ON FOUR-COMPONENT BOREHOLE STRAIN AT TAI'AN SEISMIC STATION AND ITS INTERFERENCE MECHANISM

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.     

盘锦地区水位观测与石油开采关系分析

经过多年水位观测,发现盘锦地区水位有时出现无震时“异常”变化.将辽河油田石油开采数据与本地区水位资料对比分析,结果表明:盘锦地区地下水位受油田开采影响,抽水、注水影响本区观测井水位趋势变化.为今后研究本区水位中、长趋势变化提供借鉴,为准确识别地震异常提供参考意见.     

福建省闽清梅埔井的水位大幅突降变化常调查分析

针对闽清梅埔观测井在2009年8月出现的水位大幅突降以及波动现象,通过观测仪器检查和水位值校测、降水和气压资料分析,以及周边抽水等环境干扰因素的排查等,没有找出可能的影响因素.但最后通过对测点附近的深入调查,寻找出是由于观测围墙下的暗沟内出现裂缝导致井水泄露引起水位下降的原因.本项工作表明,深入细致的调查研究是落实观测...     

Use of Groundwater Level Fluctuations near an Operating Water Supply Well to Estimate Aquifer Transmissivity

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.     

Theory and Method for Identifying Well Water Level Anomalies in a Groundwater Overdraft Area

The overexploitation of underground water leads to the continuous drawdown of groundwater levels, change of water quality and dry-up in dynamic water level observation wells. Due to land subsidence, the well pipes uplift and the observation piping systems are damaged. These environmental geology problems can present serious difficulties for the identification of earthquake anomalies by groundwater level observation. Basied on hydrogeological theories and methods, the paper analyzes the relations of the water balance state of aquifers with stress-strain conditions and the water level regime, and then discusses preliminarily the theory and method for identifying well water level anomalies in a groundwater overdraft area. The result shows that we can accurately judge the nature of the anomaly according to the diffusion character of the drawdown funnel in the well area in combination with the aforementioned theory and method and multi-year variation patterns obtained from existing data. The results of the research are helpful for distinguishing the influence of single centralized water pumping from the long-term overdraft of water on the water level, correctly recognizing water level anomalies in the groundwater overdraft area and increasing the level of earthquake analysis and prediction.     

深井热水开采对豫01井水位影响的探讨

河南省濮阳地区地下热水的开采对处于同水层的地震观测井—豫01井水位观测产生了严重的干扰影响。豫01井水位自1996年9月出现下降变化以来,其水位动态一直受到大家的关注。十几年来,地震界专家学者对有可能影响该井水位动态的诸多因素逐一进行了追踪研究。认为豫01井自1996年9月至今水位变化与中原油田抽水、注水、采油无关;其...