吉水温度微动态形成的水动力学机制研究

井水温度微动态观测越来越受到有关学者的关注，已成为我国地震地下流体动态观测的主没项之一，观测结果表明，无论是水温的正常动态还是震前的异常动态的形成，用传统的热传导或对流机制难以给出合理解释。因此笔者根据观测到的事实、异常特征与同震效应等提出了水动力学机制，即含水层变形→含水层的内孔隙压力变化→井－含水层系统内水流变化→井水温度的变化。     

应力加载作用引起地下水微温度场变化的研究综述

在地震地下流体动态观测中,水温对地震活动的响应非常敏感,井水温度微动态观测越来越受到有关学者的关注。本文收集了相关资料,以引起水温变化的水动力学机制为基础,从应力加载作用下渗流场的变化、渗流场变化引起地下水温度变化以及裂隙介质热量运移三个方面分别阐述了前人研究成果,旨在理清“含水层受力变形→井-含水层系统内水流变化→井水温度变化”的理论模式,探讨应力加载作用引起地下水微温度场变化的理论基础和技术途径。对这一领域研究成果的综合分析将有助于我们深入地研究地震孕育过程中的前兆成因机理。     

水温微动态形成的水热动力学与地热动力学机制

以井-含水层热系统分析为基础,结合井水温度(水温)动态观测到的实际结果,提出了水温微动态形成的两类基本机制,即水热动力学机制与地热动力学机制.水热动力学机制指井水温度的动态是由于水流动产生的热对流引起的变化;地热动力学机制指井区岩土中大地热流作用或热传导引起的井水温度变化.结果表明,多数同震响应是水热动力学机制下生成的水温微动态;水温的震后效应或变化则多是热传导或深部热流变化引起的,属于地热动力学机制下生成的水温微动态.少数水温微动态特征较为复杂,多是源于井-含水层系统中包含有多个水文地质特征差异明显的含水层,尚不能简单地用水热或地热动力学机制予以解释.     

首都圈地区井水温度的动态类型及其成因分析

在系统清理首都圈地区 11口高精度水温度观测井近 10年的观测资料的基础上 ,归纳出井水温度动态的多年趋势、年、月、日动态类型 ,并对其成因与特征进行分析。多年动态类型可归纳为平稳型、上升型、下降型、起伏型与复合型 ;年动态类型可归纳为平稳 -阶变型、上升型、下降型、起伏型 ;月动态类型可归纳为平稳型、平稳 -阶变型、平稳 -起伏型、下降 -起伏型、上升 -起伏型与复合型 ;日动态多为随机起伏型 ,但在 5口井发现有水温潮汐 ,绝大多数井中存在阶变或脉冲等。目前发现的影响水温动态类型的因素有大气降水的渗入补给、地表水的侧向补给、邻井地下水开采及观测井内的井水扰动等 ,此外仪器本身的不稳定性对动态类型也产生重要影响。认识上述的正常动态类型 ,排除各种干扰之后 ,仍发现井水温度有较好的映震效应 ,在一些中强以上地震之前有较好的短临异常 ,在一些远大震之时也有显著的同震异常 ,在个别远大震之前发现有震前异常。因此 ,深入研究井水温度的动态类型 ,有效地排除各种干扰 ,包括仪器不稳定产生的阶变或脉冲等 ,将会显著地增强井水温度动态监测的映震效能 ,有助于提高中国的地震短临预测能力     

河北省数字水位短临异常特征研究——以2016年唐山4.2级地震为例

2016年9月10日河北唐山发生M_S 4.2地震,以该震为例,研究河北省地下流体观测井水位震前异常变化特征。结果表明：①震中区域观测井水位异常变化形态一般为缓变型,震中外围观测井水位异常变化形态一般为骤变型;②距离震中越近,观测井水位异常出现越早,异常持续时间越长;③临近地震震中时,观测井水位异常有从震中向外围扩散的趋势;④观测井水位异常最大幅度与井震距关系不大。     

新30井新、旧观测点井水温资料初步分析

在系统清理温泉台新30号观测井水温度20多年观测资料的基础上,归纳出新30井新、旧观测点井水温动态的多年趋势和年、月、日动态类型,并对其特征进行分析。多年动态类型为下降—阶变型和下降型,年动态类型为平稳—下降型,月动态类型为平稳—下降型和平稳—上升型,日动态类型为随机起伏型。影响水温动态类型的因素有地表水的侧向补给、邻井地下水开采及观测井内的井水扰动等,此外仪器本身的不稳定性对动态类型也产生重要影响。排除各种干扰之后,仍发现井水温度有较好的映震效应。该井水温以同震或震后效应为主,对附近的中、小地震在震前也有一定的异常显示。     

夏垫断裂带地震地下流体的同震响应研究

地震地下流体已成为一种重要的地震监测手段。 本文分析夏垫断裂带上观测井的同震响应特征, 探讨观测井水位、 水温同震变化对夏垫断裂带的影响机理, 收集和整理布设在夏垫断裂带上的赵各庄井和西集井两口观测井水位和水温同震响应资料, 从响应的地震次数及发震位置、 异常幅度、 时间和形态类型等方面对其响应特征进行分析, 从震中距、 震级和井-含水层岩性等方面探讨了地下流体地震前兆异常的成因。 结果显示, 赵各庄井和西集井水位地震响应能力强于水温, 响应形态以振荡型为主, 对于M_S7.0以上地震具有显著的映震能力。 在水温资料中, 仅有赵各庄井对2008年汶川M_S8.0地震有响应, 响应幅度为0.0129℃。 综合分析认为, 井-含水层岩性影响了两井同震响应形态特征, 远场大地震产生的动态应变导致了较大的水位变幅。     

塔院井水温微动态研究

简要介绍了塔院井水温动态观测的环境与条件, 系统清理了水温多年、年、月、日动态特征并认识了水温的正常变化规律, 揭示出存在的干扰因素, 研究了典型震例, 发现了井水温度观测的最佳深度及在此观测到的水温潮汐、同震阶变与远震前兆异常等新的现象。     

北京良乡、赵各庄井水位、水温同震响应对比研究

收集了2001年以来北京地区良乡、赵各庄井水位、水温的同震响应资料,从其同震响应特征中发现,虽然两观测井水位的响应灵敏度相差不大,但良乡井水温的灵敏度要好于赵各庄井。在对比两观测井水温日变化幅度以及气泡脱逸模型的基础上,结合两观测井含水层的水文地质特征,对于两观测井水温响应灵敏度的差异给出了较为合理的解释。     

传感器放置深度对水温动态特征的影响及其机理分析

地热井的观测规范要求尽可能将水温传感器放置在井下深处, 一般放置深度应当大于100 m, 小于200 m。 然而, 近几年的观测结果表明, 水温传感器的放置深度对水温动态特征的影响较大。 在多数观测井中, 同井水温与水位的时值动态、 潮汐效应、 同震响应及震后阶变等动态特征的相关性或一致性, 多与水温传感器的放置深度有关。 本文主要探讨了传感器放置深度对水温动态特征的影响, 水温传感器放置在观测含水层中, 都受井—含水层间水流运动的影响, 会造成水温动态随井水位变化而变化; 当放置在观测含水层下部时, 水温动态则不受井水位变化的影响, 多表现为动态相对稳定。 其原因是水温动态的形成受水热动力学与地热动力学两种不同机制的控制, 此外, 井—含水层系统的条件也会产生影响。     

Relative Recovery of Thermal Energy and Fresh Water in Aquifer Storage and Recovery Systems

This paper explores the relationship between thermal energy and fresh water recoveries from an aquifer storage recovery (ASR) well in a brackish confined aquifer. It reveals the spatial and temporal distributions of temperature and conservative solutes between injected and recovered water. The evaluation is based on a review of processes affecting heat and solute transport in a homogeneous aquifer. In this simplified analysis, it is assumed that the aquifer is sufficiently anisotropic to inhibit density‐affected flow, flow is axisymmetric, and the analysis is limited to a single ASR cycle. Results show that the radial extent of fresh water at the end of injection is greater than that of the temperature change due to the heating or cooling of the geological matrix as well as the interstitial water. While solutes progress only marginally into low permeability aquitards by diffusion, conduction of heat into aquitards above and below is more substantial. Consequently, the heat recovery is less than the solute recovery when the volume of the recovered water is lower than the injection volume. When the full volume of injected water is recovered the temperature mixing ratio divided by the solute mixing ratio for recovered water ranges from 0.95 to 0.6 for ratios of maximum plume radius to aquifer thickness of 0.6 to 4.6. This work is intended to assist conceptual design for dual use of ASR for conjunctive storage of water and thermal energy to maximize the potential benefits.     

Thermal Impact of Residential Ground-Water Heat Pumps

A computer simulation study was conducted to quantify the potential thermal impact of residential water-source heat pump usage on ground-water aquifers. In a first phase of the study, weather data for nine locations throughout the country were used to estimate the energy requirements for heating and air conditioning a typical residence. These energy requirements were then translated into the volumetric water demands for a selected heat pump at each location. A representative model aquifer was then defined and its characteristics used, along with the heat pump water requirements and design ΔT's (difference between inlet and outlet water temperature) to identify the important parameters that contribute to heat transfer and to model the movement of the thermal front resulting from injection of heat pump discharge water at the nine locations. The major factor that determines the heat pump thermal impact was found to be the net amount of heat injected into, or removed from an aquifer. Other significant factors included well design, heat pump design ΔT, and physical properties of the aquifer such as thickness, porosity and dispersivity. The study showed that, in climates where winter heating demand is very nearly equal to summer cooling demands, the injection of heat pump discharge water did not cause any significant modification of the ambient model aquifer temperature. However, in hot or cold climates where air conditioning or heating demand dominates, measurable thermal changes occurred in the model aquifer. In most cases, the maximum temperature     

冷水源井水温固体潮现象及其机理研究以黄村井为例

该文对黄村冷水源井的水温固体潮现象进行了观测研究,初步解释了冷水源井的水温固体潮汐的形成机理.通过对黄村观测井进行水温梯度的详细观测及不同深度水温的对比观测研究,得到了黄村井水温潮汐现象的观测结果:① 黄村冷水源井的水温固体潮的相位与水位的相位是相反的;② 黄村井水温梯度曲线呈下凹型,特别是在含水层及受含水层进出水影响较大的附近区域下凹程度大,且随着与含水层底板距离逐渐变大,下凹程度也变小;③ 水温传感器的观测值与含水层观测距离存在一定的规律性:距离含水层越远,水温潮汐差越小, 直至潮汐变化消失.这说明冷水源井与热水井的水温潮汐现象是不同的,前者是吸热过程, 后者是放热过程,由此造成二者水-热动力学特征的不同.      

地下水潮汐现象的物理机制和统一数学方程

用新的分层承压含水层模式 ,不但考虑含水层的力学压缩性质 ,而且考虑含水层的渗流特性 ,并结合扰动信息源的频率特性 ,分别研究扰动源地球固体潮、大气潮和地表负荷潮对承压井水位和流量的影响机理 ,给出相应的偏微分方程。从方程的解释或数值解讨论扰动源与承压井含水层的力学压缩参数、渗流特性参数及与频率特性频数的关系 ,进而给出承压井水位和流量对地球固体潮、大气潮和地表负荷潮汐响应的统一数学方程及其潮汐响应函数 ,并揭示了上述几类潮汐扰动信息源对承压井水位和流量影响的物理机理     

井水位的“记忆”滞后效应

观测资料表明,井水位对信息响应存在的“记忆”滞后现象,它与一般的位相滞后不同,在鲁２９井现场试验也证明了井水位对井吕空气压力变化的响应存在的“记忆”滞后现象。利用水平层状承压含水层模式,从理论上解释了井水位对井口空气压力变化响应“记忆”滞后现象,认为这种现象与水井含水层的导水系数有关,含水层导不系数越小,这种现象越明显,用一般多元回归方法无法较好地扣除井水位中“记忆”滞后影响,作给出了一种可以扣     

STUDY FOR ABNORMAL VARIATIONS OF UNDERGROUND FLUID IN LIJIANG AREA,YUNNAN PROVINCE BEFORE LUDIAN MS6.5 EARTHQUAKE IN 2014

The study is based on the underground fluid observation data in Lijiang area, northwest Yunnan Province. The data include the water level and temperature in Dangxiao well and Jinjia well, and the ion measurements in Ganze spring. Combining with the data of regional hydrogeology, rainfall, well structures, and the geothermal gradient, we analyzed the variations of each measurement item before the Ludian M_S6.5 earthquake on August 3, 2014 and discussed the possible mechanism for the abnormal variations. The water levels of both Dangxiao well and Jinjia well are influenced by local rainfall, but the former shows hysteresis according to rainy seasons and is the long trend influence; while the latter shows synchronization between high water level and rainy season, indicating good connection between well water and shallow aquifer. The recharge water for Dangxiao well is in relatively low temperature, and the temperature sensor is located at the major connecting section between the well water and the aquifer; the water temperature variation is mainly affected by the discharge status and variation of water level. The Jinjia well is always in static level, and the temperature sensor is below the major connecting section between the well water and aquifer, so the water temperature is affected little by water level variations and in smooth fluctuation. The recharge source for Ganze spring can generally increase the contents of calcium and magnesium ions, so does the conductivity. The water level data of Dangxiao well since 2012 are decomposed with wavelet technique. The results, excluding such high-frequency components as the noise and the semidiurnal and daily wave components influenced by earth tide, are further processed with difference method in order to eliminate the trend effect. The results show that the relative change of water level is enhanced and in relatively rapid increase before the Ludian M_S6.5 earthquake; the corresponding water temperature values are high. The tendency of water level in Jinjia well displays descending, while the corresponding water temperature shows ascending. The content of calcium ion, magnesium ion, bicarbonate ion, and conductivity of Ganze spring are descending, while the content of fluoride ion is ascending. The abnormal variations of underground fluid in Lijiang area appeared in turns and were accompanied with minor earthquakes before Ludian M_S6.5 earthquake, which indicates enhancing of regional stress and increasing of fluid activity.     

Co-seismic multilayer water temperature and water level changes associated with Wenchuan and Tohoku-Oki earthquakes in the Chuan no. 03 well,China

The present paper shows analysis of water level (the distance from the land surface to the water in the well under static condition) and water temperature observed at three different levels of Chuan no. 03 well to study the changes associated with the Wenchuan earthquake of 2008 and the 2011 Tohoku-Oki earthquake. Our analysis shows co-seismic changes in water level and water temperature associated with the increase in compressive stress associated with the Wenchuan earthquake. The water level shows an increase, whereas there was drop in water temperature at the shallow depth (395 m) and enhancement of water temperature at the middle (595 m) and the bottom (765 m) layers. However, no step change in water level or temperature of Chuan no. 03 well is observed associated with the Tohoku-Oki earthquake, only seismic wave propagation-induced water level oscillation and led to co-seismic response of water temperature. The analysis of the co-seismic responses and post-earthquake adjustment processes combined with the borehole histogram and the borehole temperature gradient data clearly show co-seismic changes in water temperature that could be closely associated with the changes in the regional stress and strain state and the distribution of the aquifer and the characteristics of the aquifer. The observed temperature variation of different layers in the borehole is likely to be controlled by the flow of water in the horizontal direction.     

Characteristics and Mechanisms of Co-seismic Groundwater Responses in Tayuan Well

Co-seismic responses of the groundwater level and temperature in the Tayuan well of 68 earthquakes (M_S≥7.0) from January 2004 to September 2007 were analyzed. Results show that the Tayuan well has a strong ability to record large earthquakes worldwide, and the co-seismic response shows a pattern of water level oscillation → temperature decrease→ oscillation stop → temperature resumption. Further analyses indicate that the amplitude of the water level and temperature change is not only concerned with the epicenter distance and magnitude, but is also related to the temporal state of aquifer while the seismic wave arrives. Mechanisms of water level oscillation, temperature decrease, water level oscillation stop and temperature resumption are discussed, with the results from previous research on the co-seismic response mechanisms analyzed. These include gas escape, heat diffusion and cold water seepage. Results show that a single mechanism could not explain the co-seismic response of the Tayuan well water level to multiple earthquakes; the results were garnered from a variety of jointly acting mechanisms.     

地下水位前兆敏感水力学条件的数值模拟研究

根据弹性孔隙理论,利用数值分析的方法,研究了承压含水层对井水位的映震效果的影响,模拟结果显示：含水层系统的封闭状态对水位的映震效果有很大的影响,侧漏的大小和水头的高低会直接影响水位的观测效果,在系统封闭很好的情况下,观测水位的变化基本与水头的变化呈线性关系,此外,含水层系统的渗透性也是影响水位变化的重要条件之一,渗透性好则水位的映震效果明显。