地热对井运行系统中回灌井堵塞原因浅析及预防措施

人工回灌做为提高地热资源利用率、防止地面沉降、减少尾水排放、实现地热资源的可持续利用的最有效手段,已在地学界达成共识。基岩岩溶裂隙型热储对井回灌取得的良好效果使人们看到了回灌技术的广阔应用前景,但有些热储尤其是孔隙型热储回灌量的衰减问题一直未能得到彻底解决,各种因素引起的堵塞是主要原因。本文根据天津市历年的回灌试验,就造成地热回灌堵塞的多种原因进行了分析,并提出了可能的解决办法。     

减压井机械淤堵机制与防治方法试验研究

探讨了长江堤防减压井由于设计、施工及运行环境等因素对其产生机械淤堵的影响,研究了不同渗流介质的渗透特性以及多种介质不同组合的综合特性。除传统试验外,自行研制了径向渗透试验模型装置,采用几种物理试验方式配合,对包括地层、反滤层、滤网和井管组成的整个减压井系统,以及径向的水流与几何条件进行模拟试验。通过对室内试验与现场测试成果的综合分析,对减压井机械淤堵机制和淤堵判定进行了归纳,针对实际水动力条件和运行模式,提出了减压井反滤系统防止机械淤堵的优化设计理念。     

Confirmed faecal pollution to bore well waters of Mysore city

 Water-borne infections are the most common causes of infectious diseases in developing countries, often resulting from the lack of a protected water supply, a faulty water-supply system or improper sewage disposal. A recent study of 107 samples from bore wells of Mysore city has revealed that 51 samples (47.66%) contain Nitrate greater than 45 ppm, an indication that the water would be harmful for drinking. Out of 51 samples tested for faecal pollution, using a H₂S-strip test, 37 samples turned black and these were subjected to microbial identification. Out of these 37 samples, 63 H₂S producing strains were isolated and the H₂S producing organisms are Klebsiella ozaene;Klebsiella pneumoniae;Proteus mirabilis;Proteus vulgaris;Salmonella sp. and Citrobacter freundi. The frequency of occurrence of the above-mentioned six micro-organism strains are as follows: Proteus mirabilis (19);Proteus vulgaris (14);Citrobacter freundi (13);Salmonella sp. (8);Klebsiella pneumoniae (5); and Klebsiella ozaene (4). Klebsiella and Proteus are known to cause urinary infection and Salmonella intestional infection. Received: 7 September 1998 · Accepted: 10 November 1998     

Impact of chemical clogging on de-watering well productivity: numerical assessment

Among the processes leading to a decrease in productivity, chemical clogging is often mentioned as one of the major features. De-watering of a confined aquifer caused by an unsuitable pumping scheme produces a phenomenon involving the diffusion of oxygen in the aquifer which disturbs the geochemical conditions in the initial system. Coupled chemical and transport processes are proposed in an assessment of the impact of de-watering on the precipitation of carbonate and iron oxide. The reactions are studied for waters showing low dissolved iron concentrations such as commonly observed in drinking water supplies. The quantity and distribution of precipitated iron oxide and calcium carbonate are used in a permeability model to calculate the productivity loss. For the conditions used in the simulations, the carbonate precipitate can be neglected compared to iron deposits which remain weak. The spatial distribution is heterogeneous and quite similar to the patterns observed in the field. This shape is mainly caused by a competition between the diffusion of oxygen due to the de-watering process and the rate of precipitation of iron oxide. However, the loss of well productivity remains moderate. It is clearly shown that de-watering of the well and the associated chemical incrustations that this induces cannot alone explain field data. More complex processes involving biological clogging and accurate hydrodynamic behaviour in the closest part of the well remain to be included in the modelling approach in order to provide valuable insights into the problem of well ageing.     

Identification of suitable sites for open and bore well using ground magnetic survey

The study aims to identify a suitable site for open and bore well in a farmhouseusing ground magnetic survey in south India. It also aims to define depth to granitoid and structural elements which traverse the selected area. Magnetic data(n=84) measured, processed and interpreted as qualitative and quantitatively. The results of total magnetic intensities indicate that the area is composed of linear magnetic lows trending NE-SW direction and circular to semi-circular causative bodies. The magnetic values ranged from -137 nT to 2 345 nT with a mean of 465 nT. Reduction to equator shows significant shifting of causative bodies in the southern and northern directions. Analytical signal map shows exact boundary of granitic bodies. Cosine directional filter has brought out structural element trending NE-SW direction.Results of individual profile brought to light structurally weak zone between 90 m and 100 m in all the profile lines. Sudden decrease of magnetic values from 2 042 nT to 126 nT noticed in profile line 6 between 20 m and 30 m indicates fault occurrence. Magnetic breaks obtained from these maps were visualized,interpreted and identified two suitable sites for open and bore well. Radially averaged power spectrum estimates depth of shallow and deep sources in 5 m and 50 m, respectively. Euler method has also been applied to estimate depth of granitoid and structural elements using structural indexes 0, 1, 2, and 3 and found depth ranges from 10 m to 90 m. Study indicates magnetic method is one of the geophysical methods suitable for groundwater exploration and site selection for open and borewells.     

Chemical and mechanical clogging of groundwater abstraction wells at well field Heel,the Netherlands

Well field Heel, in the south east of the Netherlands, consists of a row of wells drilled in an anoxic pyrite-containing aquifer alongside a former gravel pit, which now serves as a recharge basin, where water is actively aerated. All wells are seriously affected by chemical (screen slot) and/or mechanical (well bore) clogging. The objective of this study is to explain this combined occurrence. A combination of chemical, hydraulic and well-maintenance data indicate three groundwater quality types: (1) oxic basin water, (2) anoxic iron-containing basin water after oxidation of the traversed aquifer, and (3) deeply anoxic native groundwater. Wells abstracting a mixture of oxic basin water and anoxic basin water and/or native groundwater experience chemical well clogging, whereas wells abstracting (only or partly) native groundwater are vulnerable to mechanical well clogging. In the end, after oxic basin water has completely oxidized the traversed the aquifer, only two groundwater quality types will be present. Wells abstracting only oxic basin water will show no clogging, and wells abstracting a mixture of native groundwater and oxic basin water will experience chemical and possibly also mechanical well clogging. In this reasoning, the sequence in abstracted groundwater quality types coincides with a sequence in well clogging: from mechanical to chemical to no clogging. As well field Heel is situated in sloping terrain, the interplay between regional hydraulic gradient and different water qualities results in one-sided chemical clogging in the upper part of the well screen during abstraction, and in the lower part during the resting phase.     

水源热泵井回灌堵塞颗粒迁移模型的建立

以地下水源热泵井回灌中的物理堵塞问题作为研究背景,建立基于质量平衡方程来模拟多孔介质中颗粒的迁移方程和颗粒的沉积造成孔隙损伤的数学模型。该模型充分考虑了颗粒流动速度修正系数、孔隙率修正系数以及颗粒在孔隙里发生捕获率3个因素;模型的建立考虑孔隙率变化的情况,在物质的迁移和堵塞的过程中,孔隙率的变化往往也是个动态的变化过程;与传统的过滤模型相比,考虑了速度折减系数和流量折减系数后新建模型更加系统、全面。该模型为解决回灌井物理堵塞的室内外试验研究提供理论依据。     

宁晋石盐田水平连通井堵塞成因分析与认识

经过20多年的发展,定向水平井连通法开采技术虽已日渐成熟,被广泛应用到采卤、采碱等水溶开采领域,但在开采生产过程中经常出现由各种原因引起的井堵现象。宁晋石盐田4对卤井,自连通投产后多次发生堵塞,经过修治后运行一段时间再次出现井堵,频繁井堵致使卤井采卤周期短、经济效益差。针对该区采卤井频繁堵塞情况,结合钻修井过程遇到的各种事故和采卤车间提供的相关数据,经过认真分析总结,主要从盐层蠕变挤破套管、夹石岩粉等杂物沉淀和盐结晶堵塞通道3个方面,阐述了宁晋石盐田的井堵原因及预防措施,可为以后卤井修井及新建卤井提供参考。     

Prevention of well clogging during aquifer storage of turbid tile drainage water rich in dissolved organic carbon and nutrients

Well clogging was studied at an aquifer storage transfer and recovery (ASTR) site used to secure freshwater supply for a flower bulb farm. Tile drainage water (TDW) was collected from a 10-ha parcel, stored in a sandy brackish coastal aquifer via well injection in wet periods, and reused during dry periods. This ASTR application has been susceptible to clogging, as the TDW composition largely exceeded most clogging mitigation guidelines. TDW pretreatment by sand filtration did not cause substantial clogging at a smaller ASR site (2 ha) at the same farm. In the current (10 ha) system, sand filtration was substituted by 40-μm disc filters to lower costs (by 10,000–30,000 Euro) and reduce space (by 50–100 m²). This measure treated TDW insufficiently and injection wells rapidly clogged. Chemical, biological, and physical clogging occurred, as observed from elemental, organic carbon, 16S rRNA, and grain-size distribution analyses of the clogging material. Physical clogging by particles was the main cause, based on the strong relation between injected turbidity load and normalized well injectivity. Periodical backflushing of injection wells improved operation, although the disc filters clogged when the turbidity increased (up to 165 NTU) during a severe rainfall event (44 mm in 3 days). Automated periodical backflushing, together with regulating the maximum turbidity (<20 NTU) of the TDW, protected ASTR operation, but reduced the injected TDW volume by ~20–25%. The studied clogging-prevention measures collectively are only viable as an alternative for sand filtration when the injected volume remains sufficient to secure the farmer’s needs for irrigation.

     

地面预注断层破碎带井筒工艺研究

地面预注断层破碎带研究采用控制性高压劈裂、小段高、水玻璃预处理、钻孔分叉综合技术和工艺，成效显著。     

Laboratory study of the clogging process and factors affecting clogging in a tailings dam

Laboratory simulation of clogging in the Lixi tailings dam (Shaanxi Province, China) is urgently required because clogging is an important factor affecting the dam stability. This work firstly presents the results of ferrous iron oxidation experiments using buffer solution. The results indicate that the ferrous iron oxidation follows first order kinetics, and the oxidation process is strongly dependent on pH, a higher pH resulting in a higher oxidation rate. Furthermore, when the pH exceeds 7.0, the oxidation rate constant increases significantly. Secondly, a column experiment was carried out under the conditions of the pH ranging from 6.8 to 7.5 and the natural oxygen supply. Ferrous iron oxidation and precipitation were found to reach equilibrium under these conditions. After 23 days, the column experiment was stopped when the clogging materials blocked the column outlet. The clogging materials were found to be a mixture of ferric hydroxide and its converted products, and these existed in amorphous form with a loose cluster microstructure according to the results of XRD and SEM.     

人工回灌过程中富里酸和Cu(Ⅱ)对多孔介质悬浮物堵塞的影响

地下水人工回灌是解决地下水超采问题的有效措施,悬浮颗粒物堵塞是影响回灌进行的技术瓶颈。目前多数研究聚焦在悬浮物堵塞方面,然而地表回灌水中重金属离子以及腐殖质对多孔介质物理堵塞的影响缺乏研究。本研究采用室内渗流砂柱试验研究富里酸、Cu(Ⅱ)以及两者共存对多孔介质悬浮物堵塞的影响,分别采用高岭土（SS组）、富里酸+高岭土（SS+FA组）、富里酸+Cu(Ⅱ)+高岭土（SS+FA+Cu组）配置模拟回灌用水。研究结果表明：（1）回灌结束时,SS组、SS+FA组、SS+FA+Cu组多孔介质整体相对渗透系数K’分别降至0.233,0.095,0.182。SS组和SS+FA+Cu组在中上层（0~7.50 cm）相对渗透系数K’均降至0.28以下,而在底层（7.50~10.50 cm）相对渗透系数K’仅降至0.45左右,说明2组多孔介质中上层重度堵塞（0相似文献   

跟管钻进在大口径页岩气井浅部复杂地层中的应用 ——以黔水地1井导管段为例

桂中-南盘江地区的浅部地层裂隙、溶洞发育,破碎带多,井漏、井垮严重,泥浆护壁钻进成孔难度较大。针对该类地层,首次将跟管钻进技术引入大口径页岩气井钻探——黔水地1井导管段钻探,有效地解决了该井导管段的成孔难等问题。并通过系统总结该技术在黔水地1井工程施工中的实际应用情况,为今后类似工程提供了宝贵经验和建议。     

莱州湾南岸海咸水入侵的原因分析及防治对策

莱州湾南岸的昌邑、寒亭、寿光等市(区)，是我省沿海发生海咸水入侵地质灾害较严重的地区之一。自70年代中期发现海咸水入侵以来，入侵速率逐年增加，到1992年，入侵面积已达295．5km^2，给工农业生产和人民生活造成了严重损失。该区海咸水入侵以咸水入侵为主。笔者在分析区域地质背景条件基础上，从水动力学和水化学方面对海咸水入侵的发灾机理进行了探讨。指出地下淡水过量开采是海咸水入侵的根本原因；此外，沉积环境、河流上游来水量减小及风暴潮等对海咸水入侵有加剧作用。从地学角度，提出了全流域综合治理、合理开发利用淡水资源、建设地下水库、跨流域调水，建立抽水槽工程等防治对策。     

SPH modeling of tidal bore scenarios

Natural Hazards - The paper presented a smoothed particle hydrodynamics (SPH) method to study the three-dimensional (3D) tidal bore scenarios. The SPH method is a mesh-free particle modeling...     

煤矿立井井壁破裂的机制及防治措施

文章在详细调研当前煤矿立井井壁破裂现状和特点的基础上，对当前煤矿立井井壁破裂机理的研究成果，尤其是附加应力说进行了分析总结，并针对兴隆庄煤矿立井井壁破坏的特点和状况，分析研究了其破坏机制，给出了防治方法与技术措施，实践证明效果良好，为井壁破坏的治理提供了参考依据。     

煤层气水平井煤粉产出规律及其防治措施

从实际资料入手,深入分析煤层气水平井煤粉形成原因、煤粉产出规律及防治煤粉措施。分析结果表明：井壁原始应力状态改变、煤岩物质成分及组成、钻具的碾磨作用和钻遇煤层段井眼轨迹弯曲大煤层局部受到钻具挤压以及排采工作制度改变使降液速率变化大等是影响煤层气水平井煤粉形成的主要原因;黏土矿物是煤粉的主要来源,且黏土矿物含量越高,煤层出粉的可能性越大;排采早期产出的煤粉颗粒直径在几十微米到几百微米之间,粒径变化明显,表明排采早期产生的煤粉以钻具碾磨和井壁原始应力状态改变形成为主,排采后期产出的煤粉颗粒直径主要在几十微米左右,粒径分布相对均匀,表明排采后期产生的煤粉以煤层煤岩物质成分组成和排采工作制度变化影响形成为主;加强水平段循环清洗工作,优化合理的筛管缝隙尺寸、筛管直径、筛管长度等综合工艺技术,优选合适的排煤粉设备、制定合理的控煤粉排采制度等是煤层气水平井煤粉防治的主要措施。     

滑坡涌浪的产生与传播波形分析与计算

在水平匀速滑坡涌浪传播过程中,当滑坡体匀速前进时,会形成一个冲击波,停止前进后,在滑坡体与冲击波之间又形成一个稀疏波,当稀疏波追赶上冲击波时,两个波则会发生相互作用。对稀疏波与冲击波相互作用后产生的反射冲击波和入射冲击波的情况进行了定量研究。从入射冲击波的轨迹方程入手,通过分析和计算,分别得到了入射冲击波和反射冲击波波高、波速等一些定量的关系式,并用简单的计算方法进行了求解。     

煤层气井杆管偏磨规律及偏磨防治技术

从偏磨井实际资料入手,运用煤层气开发学、统计学等方法,研究了煤层气井杆管偏磨特征和偏磨规律,并探讨了煤层气井杆管偏磨防治措施。研究发现:杆管偏磨是煤层气井排采中普遍存在的问题;杆管偏磨的位置基本上都在泵体以上的200 m有限范围之内;偏磨基本上发生在排采1 a时间之内,并且在随后的排采时间里偏磨程度有所减轻;井眼弯曲、井深大于500 m的井以及抽采冲次大于3次/min的井比较容易发生偏磨;产出液中的酸性成分和煤粉也能加速杆管偏磨程度。分析认为,优选煤层气井排采设备,合理控制煤层气井排采参数,以及针对煤层气井的自身特点采取一些综合防治措施,是防治煤层气井杆管偏磨的主要手段。     

Quantification of groundwater recharge and river bed clogging by daily water level measurements in a check dam

Check dams are one of the methods of managed aquifer recharge to augment groundwater storage in regions with non-perennial rivers. The objectives of this study were to quantify the groundwater recharge from a check dam in the Arani River, north of Chennai, India, and to assess the clogging of the riverbed. The water level in the check dam was measured daily for 3 years from 2010 to 2013. Other field investigations carried out include measurement of the topographic elevation of the riverbed using the differential global positioning system. Based on the water balance method, the quantity of water evaporated and recharged was estimated. A comparison of 3-year daily water level measurements indicated that there is no clogging in the riverbed during the study period, as this check dam is fitted with a sluice gate which is operated at appropriate times to flush out the sediments.