The influence of the chemical composition of stratal water of the oil-gas fields of western Siberia on reservoir exploitation

In this work, the hydrochemical properties of the stratal water of several oil-gas fields of Western Siberia with normal and inverse vertical hydrochemical zonation are discussed. Maps of the injected water distribution, which were created on the basis of high bicarbonate ion concentration in the stratal water (to 30 eq wt %), as well as the computer modeling results of calcite precipitation in stratal water that results from the mixture of two water types: calcium chloride (injected) and sodium bicarbonate (stratal), are given. In addition, the need to consider the hydrochemical type of water when choosing the technique of hydrochemical data processing was established.     

多矩形图解法及其在塔里木盆地中的应用

多矩形图解法（MRD）采用9个相邻的多矩形坐标系，分别代表9种地下水类型，它具有容纳大量地下水化学分析数据的功能。图解结果不但可以清楚地显示地下水中阴、阳离子含量的信息，而且也提供了更明晰、易懂的水化学类型的信息。本文简要地叙述了MRD法的原理，并应用该方法分析了塔里木盆地各流域地下水的水化学类型，结果表明：MRD法可以清晰地表征塔里木盆地地下水水化学类型的空间变化特征。     

Contribution of multivariate statistical techniques in the hydrochemical evaluation of groundwater from the Ouargla phreatic aquifer in Algeria

A hydrochemical evaluation of the hydrogeological surface aquifer of Ouargla was conducted using 17 samples of water. The analysis of the samples focused on the determination of calcium, magnesium, sodium, potassium, chloride, sulfate, bicarbonate, and nitrate, while electrical conductivity, temperature, and pH were measured on the ground. The obtained data are processed by multivariate techniques with a varimax rotation approach after standardization. The chemical data follow four factorial axes that provide a cumulative total variance explained by 67 %. Considering the EC as an additional variable, the matrix components after varimax rotation have identified a first axis related to NaCl, a second axis associated with CaSO₄, a third axis of HCO₃ and a fourth axis of NO₃. These variables control a significant part of the chemistry of the groundwater in the region of Ouargla.     

韩城矿区奥灰水化学特征及形成机制探讨

以岩石化学成分、水质分析、同位素组分以及水质动态长期监测等资料为基础，分析了矿区岩溶水介质的赋存与分布等水文地质背景，重点研究了水化学组分特征及其形成机制。结果表明：由矿区边部至中深部，水化学类型由重碳酸硫酸钙镁型向硫酸盐氯化钠钙型过渡，TDS随含水层埋深升高而水质变差，水化学组分主要由溶滤作用经去膏盐化和脱白云岩化过程形成，开采井群水质变劣的主因是矿区中深部高矿化水的混合作用所致。     

广西新寨矿泉水出露特征及形成机理

新寨矿泉水属重碳酸钙钠型低钠、低矿化度的含氯硅酸矿泉水，是来自花岗岩体中较深层的构造裂隙水、其水质、水量、水温十分稳定，为花岗岩体中较深层的构造裂隙水。矿泉水中有益元素的物质组份来源于花岗岩体，偏硅酸和氡含量达到国家标准，具有经济价值。     

Suitability assessment of shallow and deep groundwaters for drinking and irrigation use in the El Khairat aquifer (Enfidha, Tunisian Sahel)

The El Khairat aquifer is an important groundwater aquiferous system, which is considered a major source for drinking and irrigation water in Enfidha in Tunisian Sahel. The analysis of groundwater chemical characteristics provides much important information useful in water resources management. Assessing the water quality status for special use is the main objective of any water monitoring studies. An attempt has been made for the first time in this region to appreciate the quality and/or the suitability of shallow and deep groundwater for drinking and irrigation. In order to attend this objective, a total of 35 representative water samples were collected during February 2007 from both boreholes (17) and wells (18); and analyzed for the major cations (sodium, calcium, magnesium and potassium) and anions (chloride, sulphate, bicarbonate, and nitrate) along with various physical and chemical parameters (temperature, pH, total dissolved salts, and electrical conductivity). Based on the physico-chemical analyses, irrigation quality parameters like sodium absorption ratio (SAR), residual sodium carbonate (RSC), percentage of sodium (Na%), and permeability index (PI) were calculated. In addition to this, iso-concentration maps were constructed using the geographic information system to delineate spatial variation of qualitative parameters of groundwater samples. The correlation of the analytical data has been attempted by plotting different graphical representations such as Piper, Wilcox, and US Salinity Laboratory for the classification of water. The suitability of the water from the groundwater sources for drinking and irrigation purposes was evaluated by comparing the values of different water quality parameters with World Health Organization guideline values for drinking water. A preliminary hydrochemical characterization shows that most of the groundwater samples fall in the field of calcium–magnesium–chloride–sulphate type of water. Majority of the samples are not suitable for drinking purposes and far from drinking water standards. The high EC value and the percentage of Na in most of the groundwater render it unsuitable for irrigation. Wilcox classification suggested that around 50% of both deep and shallow groundwater samples are unsuitable for irrigation. According to the US Salinity Classification, most of the groundwater is unsuitable for irrigation unless special measures are adopted.     

城市化对岩溶水系统化学组分演化的影响——以重庆市南山老龙洞地下河为例

为研究城市化作用下的岩溶区地下水水质演变状况,基于2008-2012年对老龙洞地下河的pH值、电导率、水温、K+、Na+、Ca2+、Mg2+、HCO3-、Cl-、NO3-、SO42-、PO43-等水物理化学指标的连续监测,分析了老龙洞地下河流域水质的演变趋势,并对2011年8月的单场降雨条件下地下河水质的动态变化进行主成分分析(PCA)。结果表明,在城市化过程中,地下河水Na+、Cl-、PO43-、Ca2+、Mg2+、HCO3-等离子浓度受人类活动影响而明显上升,NO3-、SO42-浓度则因为城市化效应增强和农业活动强度的降低而下降。老龙洞地下河水补给来源复杂,其中碳酸盐岩地质背景、人类活动及水土流失对地下河水质变化起着决定作用。城市化水平的提高、区域环境的变化,使得老龙洞地下河的水质也处于不断变化中,从硝酸盐、硫酸盐的年际变化看,地下河水质已有较大改善。      

论川西坳陷上三叠统气田水化学场及其分带

在阐述川西坳陷地质构造背景基础上，根据大量水化学测试数据，概括了上三叠统气田水化学成分基本特征，勾划了气田水10个水化学参数化学场图，揭示了气田水化学分布规律性，并划分了正向和斜向垂直水化学分带。对于相关的气田水渗流场和地下水成因的研究具有重要的理论意义。     

A study on hydrochemical characteristics of surface and sub-surface water in and around Perumal Lake,Cuddalore district,Tamil Nadu,South India

Hydrogeochemical investigations are carried out in and around Perumal Lake, Cuddalore district, South India in order to assess its suitability in relation to domestic and agricultural uses. The water samples (surface water = 16; groundwater = 12) were analyzed for various physicochemical attributes like pH, electrical conductivity (EC), sodium (Na⁺), potassium (K⁺), calcium (Ca²⁺), magnesium (Mg²⁺), chloride (Cl⁻), bicarbonate (HCO₃ ⁻), sulfate (SO₄ ²⁻), phosphate (PO₄), silica (H₄SiO₄) and total dissolved solids (TDS). Major hydrochemical facies were identified using Piper trilinear diagram. Hydrogeochemical processes controlling the water chemistry are water–rock interaction rather than evaporation and precipitation. Interpretation of isotopic signatures reveals that groundwater samples recharged by meteoric water with few water–rock interactions. A comparison of water quality in relation to drinking water quality standard proves that the surface water samples are suitable for drinking purpose, whereas groundwater in some areas exceeds the permissible limit. Various determinants such as sodium absorption ratio (SAR), percent sodium (Na%), residual sodium carbonate (RSC) and permeability index (PI) revealed that most of the samples are suitable for irrigation.     

Hydrochemical characteristics and the effects of irrigation on groundwater quality in Harran Plain,GAP Project,Turkey

Improper design, faulty planning, mismanagement and incorrect operation of irrigation schemes are the principle reasons for the deterioration of groundwater quality in a large number of countries, in particular in semi-arid and arid regions. The aim of this study is to determine the dimensions of groundwater quality after surface irrigation was begun in the semi-arid Harran Plain. Physical and chemical parameters of the groundwater including pH, temperature, electrical conductivity (EC), sodium, potassium, calcium, magnesium, chloride, bicarbonate, sulphate, nitrate, nitrite, ammonium, total phosphorus, total organic carbon and turbidity were determined monthly during the 2006 water year. The quality of the groundwater in the study area was assessed hydrochemically in order to determine its suitability for human consumption and agricultural purposes. In the general plain, the EC values measured were considerably above the guide level of 650 μS/cm, while nitrate in particular was found in almost all groundwater samples to be significantly above the maximum admissible concentration of 50 mg/l for the quality of water intended for human consumption as per the international and national standards. Total hardness reveals that a majority of the groundwater samples fall in the very hard water category. Interpretation of analytical data shows that Ca–HCO₃ and Ca–SO₄ are the dominant hydrochemical facies in the study area.     

Major ion geochemistry of groundwaters from southern Nevada and eastern California, USA

The dissolved ionic constitutents of groundwaters are,in part,a recored of the minerals and rocks in aquifers through which the water has flowed.The chemical composition and association of these major ions in groundwaters have been used to trace groundwater flow paths and sources,In general,the chemical compostion of water in carbonate-rock aquifers in dominated by calcium,magnesium,and bicarbonate,whereas sodium,chloride,and sulfate can be dominant ions in the water that comes from volcanic aquifers or clay minerals.Since the 1990‘s,we have dealt with the geochemistry of groundwaters from more than 100 springs and wells in southern Nevada and eastrn california ,USA for major solutes and trace elements.This paper compiles the hydrochemical data of major ions of these groundwaters.Based on major ion geochemistry,groundwaters from southern Nevada and eastern California can be classified as carbonate aquifer water,volcanic aquifer water,and mixing water (either mixing of cabonate and volcanic aquifer waters or mixing with local recharges),Piper and stiff diagrams of major ions have graphically shown the general chemical characteristics,classification,and mixing relationships of groundwaters from southern Nevada and eastern California.     

和村-孙庄盆地富锶矿泉水赋存地质条件

和村-孙庄盆地锶矿泉水属低钠低矿化度含锶重碳酸钙镁型中性低温矿泉水。通过对盆地构造、岩溶发育、地下水动态等特征的分析与研究认为,奥陶系中统峰峰组二、三段岩溶裂隙含水层为盆地内的主要富锶矿泉水地层,锶元素来源于碳酸盐和岩浆岩,矿泉水中氚浓度（33．86±3．44TU）含量表明,该矿泉水形成年龄为10～20a,具有远源补给、深层循环特征。     

Characterization of groundwater contamination using factor analysis

 The effluent contamination of groundwater at two industrial sites at Visakhapatnam, India, was studied using factor analysis. Thirty groundwater samples near a zinc smelter plant and 19 from the polymers plant were analyzed for specific conductance, chloride, bicarbonate, sulfate, calcium, magnesium, sodium, and potassium. The data were subjected to R-mode factor analysis and the factor scores transferred to areal maps. While magnesium and sulfate are the dominant contaminants at the zinc site, sodium, chloride, and bicarbonate from the effluent are affecting groundwater in the polymers area. Contour maps for each factor suggest the areal extension of the contaminants. Received: 1 March 1995 · Accepted: 18 September 1995     

柴达木盆地西部油泉子凹地晶间卤水层水文地质及水化学特征

油泉子凹地位于柴达木盆地西部,凹地中蒸发岩的晶间孔隙发育,包含了大量的高浓度卤水,KCl品位高,富水性中等,水化学类型有氯化物型、硫酸镁亚型、硫酸钠亚型。研究表明,周边山区岩石中钾、硼、锂、钠、镁等元素物理风化后经流水搬运,形成了研究区丰富的钾盐矿物质;相关元素比值反映了矿区卤水陆相来源、溶滤水的成因特点。研究显示,研究区内地下水的密度、矿化度均有由西向东逐渐变淡的趋势;水文地质条件表明,季节性洪水、大汽降水是卤水重要的补给源。研究区地势低洼,地下水的排泄方式主要为蒸发排泄,形成了具有典型内陆蒸发型的水文地球化学特征,因此富集了大量高矿化度、且含多种金属离子的咸卤水。     

Health risk assessment of fluoride with other parameters in ground water of Sikar city (India)

Geochemical processes are identified as controlling factors of groundwater chemistry, including chemical leaching and fluoride contaminations. These geochemical processes are identified using characterization of the major physico-chemical parameters of ground water from northern part of Sikar city. For this purpose, 15 ground water samples have collected and analyzed for different water quality parameters, such as pH, EC, TDS, TH, TA, DO, calcium, magnesium, sodium, potassium, carbonate, bicarbonate, chloride, nitrate, sulfate and fluoride with the help of standard methods recommended by American Public Health Association. The analysis indicated that fluoride concentrations in four samples are at alarming state as compared to the World Health Organization standards for drinking purposes, thereby suggesting the need for treatment and precautionary measures for use of the particular ground water. The increased fluoride level in the ground water of Sikar city is due to the some geological process such as dissolution of fluoride rich mineral (fluorspar) in the favorable environment. To classify the ground water ability for different purposes various graphical plots like Piper tri-linear, Durov, Schoeller, Bar, Scatter diagrams have been drawn. On the basis of physico-chemical, graphical and statistical analysis (Spearman’s Rank correlations), various dimension of improving water quality for drinking purposes have also been suggested.     

乐东县龙沐湾地热田地热流体化学特征及质量评价

海南省乐东县龙沐湾地热田属于隐伏小型中低温地热田,地热田面积约12 km2,呈南北半月形带状展布,该地热田内3口地热井为32℃～42℃。通过对地热田内地热井的水化学资料分析得出,地热田水化学类型以HCO3-Na·Ca型为主,地热流体水化学组分基本处于稳定状态。同时对地热流体质量评价,将地热田地热流体命名为重碳酸钠钙型硅温水,可作饮用天然矿泉水,不宜作生活饮用水、渔业用水和农业灌溉,地热流体不具有腐蚀性且通过碳酸钙结垢趋势判断为不结垢。     

电感耦合等离子体法测定灰岩中的钙镁钾钠铝钛铁锰

灰岩样品的主要成分为碳酸钙,而镁、钾、钠、铝、钛、铁、锰的含量非常低,测试的灵敏度要求很高。该文采用一次溶矿电感耦合等离子体法直接测试灰岩中的镁、钾、钠、铝、钛、铁、锰。实验表明：在5％的盐酸介质中测试镁、钾、钠、铝、钛、铁、锰能取得很好的效果。通过测试国家标准样品,与国家标准值相比较,分析结果基本一致,准确度和精密度均令人满意,镁、钾、钠、铝、钛、铁、锰元素的相对标准偏差≤0．07％。钙元素的标准偏差≤0．15％。     

潜江凹陷古盐湖水文化学面貌的再造

古盐湖水文化学面貌的再造是研究地下卤水起源和演化问题的基础。配方从潜江凹陷古盐湖水水质的形成特点,演化和古盐度的计算,再造了潜江凹陷古盐湖的水文化学面貌。在古盐度的计算过程中,采用了调参的方法解决公式的应用问题,所取得的盐度数据对了解古盐湖水质演化的概貌具有一定意义。     

Hydrogeochemical controls on shallow alluvial groundwater under agricultural land: case study in central Portugal

A hydrogeochemical study employing graphical, multivariate statistical, and modeling tools was conducted in an area of alluvial deposits in the Mondego river basin, to determine the factors and processes controlling the shallow groundwater chemistry. Groundwater was collected from 29 observation wells in six sampling campaigns, between March 2001 and September 2002. Samples were analyzed for basic physicochemical parameters, major ions and some minor ions. Hierarchical cluster analysis was applied to the data set, including both the spatial and temporal monitoring data and resulted in the definition of eight distinct water types. With the aid of hydrochemical (and physicochemical) scatter plots, it was possible to identify the main processes controlling the groundwater chemistry: (1) evapotranspiration and recharge; (2) calcium and magnesium carbonate and CO₂ dissolution; (3) nitrate leaching from agriculture; (4) oxidation and reduction; and (5) cation exchange. These processes are frequently common to more than one water type but unique in combination and/or extent, in space and/or time. Geochemical modeling of the water types (using PHREEQC) allowed the validation and, to a certain extent, quantification of the processes that affect the shallow groundwater evolution. These tools can provide an essential support for the assessment of groundwater vulnerability to contamination and for the elaboration of groundwater resource management strategies.     

Hydrogeological and hydrochemical characterization of two karstic discharge areas in San Luis Potosí, Mexico

Two karstic discharge areas, Río Verde (RV) and Ciénega de Cabezas (CC), located in a distance of 80 km to each other are chosen to determine the influence of local variations in geology and climatic condition on water chemistry and to examine if the groundwater, supplying the discharge areas, undergoes the same evolution and has a common source. Both study areas are situated on the carbonate platform Valles-San Luis Potosí and comprise a similar geological setting, but despite of their spatial vicinity the climate is semiarid in RV and humid in CC presenting an important factor on the amount of discharge and the concentrations of ions in the discharge. The investigation encompasses discharge, hydrochemical and physico-chemical parameter evaluations as well as the determination of saturation indices, hydrochemical modelling and water type characterization of surface water samples to derive knowledge of the groundwater systems. Scatterplots and saturation indices were used to proof the influence of lithological variability. Both study areas represent normal alkaline water, marked by high concentrations of calcium and magnesium with varying concentrations of bicarbonate and sulphate. In RV, the water interacts with dolomite rocks and gypsum layers, whereas in CC the dolomite content is depleted and the influence of limestone rocks increases. The climatic impact on the groundwater in RV is noticeable by the increase in ionic concentrations due to higher evaporation. In CC the higher amount of precipitation dilutes the groundwater and causes decreasing ionic concentrations.