Hydrogeological Wells Research Articles

Integration of seismic and sedimentological methods for analysis of Quaternary alluvial depositional systems

Due to the high potential of unconsolidated sedimentary bodies to form aquifers and reservoirs, an identification of their exact geometry and location is of great importance. Current conceptual models of these bodies are often developed using scattered data from hydrogeological wells. More reliable results can be achieved by application of methods that can provide continuous subsurface record of the actual geological situation in the investigated area. In this article, a combination of two different approaches is used on a case study of alluvial Quaternary sediments from the East Slovakian Basin, including the discussion how these methods contribute to the final geological interpretation. First, a sedimentological analysis was performed with the use of data acquired from auger drilled hydrogeological wells, which enabled identification of depositional processes, depositional systems and the possible source areas. Due to the shallow depth of the studied area, a second approach based on the geophysical measurement using seismic refraction and tomography was applied. This method provided information mainly about the geometry of these systems, the position of the sediments within them and highlighted where the main changes in the sediment texture and composition occurred. Integration of both methods allows us to obtain a more precise image of the subsurface, which contributes to a better understanding and prediction of the occurring sediments in the studied area.

Hydrogeophysical characterization of the porous and fractured media (chalk aquifer in the Beauvais, France)

This study is aimed to investigate the principal aquifer in the northern part of Paris (Beauvais region) which is materialized by the Senonian chalk deposits. This aquifer supplies water to the principal region in the north and in particular the Picardie and Artois region. In order to characterize the chalk aquifer of this area, a wide pluridisciplinary research program based on the well logging and near surface geophysics surveys (seismic refraction and electrical resistivity tomography) is in progress. These surveys were carried out within the experimental site of the LaSalle Beauvais Polytechnic Institute and its hydrogeological boreholes. The heterogeneous distribution of the seismic velocities in the complex aquifer and of the physico-chemical properties (conductivity, temperature and gamma-ray) of the chalk aquifer were revealed by the analysis and the interpretation of the seismic lines and data logging, which are linked to changes in lithology and water properties at the place of the hydrogeological wells. The fracturation investigation identified during this work makes it possible to consider the relationship between the degree of the fracturation and the variation of the hydrogeological parameters (hydraulic conductivity, porosity) and physico-chemical parameters (electrical conductivity and temperature). The interface between vadose and saturated zones was assessed by the measurement of the water conductivity, the variation of the average temperature and by the cuttings analysis in particular at the level of the capillary fringe of the chalk aquifer. The presence of the saturated depth is confirmed by the piezometric investigation. The interpretation of the well logging by using gamma-ray is consistent with the seismic and electrical analysis: the three principal layers are composed of silt and clay with cherts, soft chalk, as well as hard chalk.

EVALUATION OF STRESS-STRAIN STATE OF ROCK MASS

Abstract. A new method of determining the stress-strain state of the rocks without dropping its individual parts on the basis of combination of observations of the dynamics of piezometric level in special hydrogeological wells of pre-planned network and by the change in the diameter of wells measured by photo elastic sensors is proposed. With the beginning of the formation of the stress-strain state of the geological environment, the chaotic structure of hydro-geodynamic field(HGD-field) goes into the abnormal condition of a certain form, in accordance with the geometric shape and sizes of the geological structure. Closed lines of equal abnormal values of piezometric levels form geometric circular structures in the Central parts of which are observed their most anomalous values corresponding to the greatest extent of stressstrain state of rock massif. Within abnormal (disturbed) HGD-field is carried out the measurement of the diameters of the wells, fixed by photoelastic sensors which clarify the concrete stress-strain plot (voltages source) of the rock massif. Well drilled for measuring by photoelastic sensors of changes in their diameters, are arranged in the rock massif in a staggered manner, and the special hydrogeological well, drilled up to an isolated water system for the registration of anomalous (perturbed) HGD-field are locatedin two mutually perpendicular profiles, taking into account the geometric shape of the monitored rock mass. The combination of observations according to a pre-planned network of piezometers and wells with photoelastic sensors will allow to get a more accurate picture of the stress-strain state of the investigated deposits of rock without pass of its separate parts.

Опыт оборудования гидрогеологической скважины криогенно-гравийным фильтром

Опыт оборудования гидрогеологической скважины криогенно-гравийным фильтром

Coupling fracture facies with in-situ permeability measurements to generate stochastic simulations of tight carbonate aquifer properties: Example from the Lower Cretaceous aquifer, Northern Provence, SE France

The relationships between fracture facies and permeability distribution have been explored using a well-constrained 3D implicit structural model of hemipelagic low porosity/low permeability carbonate from the Northern Provence region, SE France. Fracture and permeability facies were determined using an extensive dataset of 99 hydrogeological wells. Data processing was undertaken using a step-by-step approach, involving: (i) identification of the fracture facies based on well logs detailing structure and stratigraphy; (ii) determination of permeability facies from the a priori correlation between the dimension of the hydraulic radius of influence (deduced from slug test analyses) and the type of reservoir heterogeneity (fissure, fracture, fault zone, etc.); (iii) three dimensional plot of fracture and permeability facies in the geological model using a variographic analysis of data. Thirty-three sequential indicator simulations (SIS) based on geostatistic analyses were realised on both fracture and permeability facies. Finally, a connectivity algorithm was developed to compute the probability of connection between selected infiltration areas and the major aquifer springs via moderate- to high-permeability geological bodies. Key results are: (i) fault zones have a greater role in controlling permeability facies distribution than on fracture facies repartition; (ii) there is little correlation between permeability and fracture facies distributions; (iii) connectivity results highlight the compartmentalisation of aquifers in the Cadarache area, the extensions of permeable geological bodies being limited by the N130 faults.

The hydrogeological well database TANGRAM©: a tool for data processing to support groundwater assessment

At the Department of Earth and Environmental Sciences of the University of Milano-Bicocca (DISAT-UNIMIB), a hydrogeological well database, called TANGRAM©, has been developed and published on line at www.TANGRAM.samit.unimib.it, developing an earlier 1989 DOS version. This package can be used to store, display, and process all data related to water wells, including administrative information, well characteristics, stratigraphic logs, water levels, pumping rates, and other hydrogeological information. Currently, the database contains more than 39.200 wells located in the Italian region of Lombardy (90%), Piedmont (9%) and Valle d’Aosta (1%). TANGRAM© has been created both as a tool for researches and for public administration’s administrators who have projects in common with DISAT-UNIMIB. Indeed, transferring wells data from paper into TANGRAM© offers both an easier and more robust way to correlate hydrogeological data and a more organized management of the administrative information. Some Administrations use TANGRAM© regularly as a tool for wells data management (Brescia Province, ARPA Valle Aosta). An innovative aspect of the database is the quantitative extraction of stratigraphic data. In the part of the software intended for research purposes, all well logs are translated into 8-digit alphanumeric codes and the user composes the code interpreting the description at each stratigraphic level. So the stratigraphic well data can be coded, then quantified and processed. This is made possible by attributing a weight to the digits of the code for textures. The program calculates the weighted percentage of the chosen lithology, as related to each individual layer. These extractions are the starting point for subsequent hydrogeological studies: well head protection area, reconstruction of the dynamics of flow, realization of the quarry plans and flux and transport hydrogeological models. The results of a two-dimensional distribution of coarse, medium and fine sized material in the first 80 meters of depth are presented here for a study area located within the Province of Brescia (Italy).

SOME RESULTS OF GEOPHYSICAL AND HYDRO-GEOLOGICAL RESEARCHES OF THE ISLAND «ZMEINIY» EXECUTED BY THE DGE «DNEPROGEOFIZIKA»

In the beginning of XXI century DGE “Dneprogeofizika” has executed complex geophysical researches on island. By their results explorative hydro-geological wells which have established presence of underground waters of soil type with static level from 36.9 to 32.0 m have been drilled. Depths of distribution of poorly-mineralization waters are marked below a sea level (to 80 m). For the control of level and a mineralization of underground waters while in service well the monitoring system has been created. The received results have allowed increase a pumping performance of water from a well with 3 м3 to 5 м3.

Udostępnianie wód termalnych w Uniejowie – rys historyczny

The article presents the history of the exploitation of geothermal waters in Uniejów. Interest in the use of geothermal waters in the area Uniejów began in the late 1960s, whe the parameters of water examined during the drilling of the well Koło IG-3 were found to be satisfactory. The first hydrogeological well was drilled in Uniejów in 1978. The next two wells were drilled in the early 1990s as part of a large project, which aimed at creation of two doublets and multi-variant use of geothermal waters in Uniejów. Unfortunately, the opening of geothermal installations had to wait until the year 2001. The article also describes the current development of geothermal energy and water in Uniejów.

Położenie fizycznogeograficzne miasta i gminy Uniejów

Two attributes are important in the location of the Uniejów town and commune: its lying in the centre of the country (ca. 48 km west of the geometric centre of Poland) and in the borderland in different physicogeographical divisions. Uniejów is situated in the southern part of the Koło Basin near the boundaries with Łask Plateau, Sieradz Basin and Turek Plateau. In the past, the factor most important for the development of Uniejów was its location in the placewhere the Warta valley and Warsaw–Berlin valley connected because major routes running along these valleys facilitated transport and settlement. Present development of the town is connected with geothermal waters found in Lower Cretaceous sediments within Lodz Basin. The first hydrogeological well was drilled in Uniejów in 1978. This article presents the location of Uniejów within the physicogeographical, geological, geomorphological, and botanical units and on the map of Poland’s climatic conditions.

Управление рисками при эксплуатации гидрогеологических скважин

The system of risk management principles is formed. The most acceptable mode for technical condition research of operational
 hydro-geological wells is offered. The risk management algorithm is developed. Mathematical model for operation reliability
 assessment of wells is created.

Coal in the Mura Formation (Pontian) between Lendava (Slovenia) and Mursko Središće (Croatia), and in the wider area of NE Slovenia

Geological setting, occurrences, extent, quality and reserves of coal seams in the Mura Formation of the Mura- Zala Basin in NE Slovenia are presented in the paper. The Mura-Zala Basin consists of antiforms and sinforms bounded by normal and reverse faults. It is filled in its deepest parts by more than 4000 m of clastic sediments from the late lower Miocene upwards. It represents one of the western basins of the Pannonian Basin System. The coal-bearing Mura Formation is of the Pontian age. It is more than 1000 m thick and consists of marls, silts and sands, and of numerous (10-30) beds of brown coal which are relatively thin. The coal-bearing depositional system is clearly paralic. Original peat-lands developed in freshwater environments while bulk sedimentation in-between (according to paleontological investigations of the Ostracoda microfauna) took place under influence of brackish waters. Well ascertained coal beds are only those in a restricted area (ca. 60 km2) between Lendava (Slovenia) and Mursko Središće (Croatia), where the coal beds dip almost from the surface (under 10-20 m of Quaternary gravel) downwards to depths of not more than 400 m. The whole coal-bearing bed-set in the Lendava area is about 130 m thick but contains only three coal seams which are generally 1.0-2.2 m thick. At the "as received basis" (25-30 % moisture content, 15-20 % ash yield), the net calorific value of the Lendava coal reaches ca. 14.5 MJ/kg, and the average sulphur content is ca. 1.6 %. The Mursko Središće coal is of a similar quality. Tectonic structure of coal beds is simple and uniform. In the Ormož-Selnica Antiform (which continues to the Budafa - Lovászi Antiform in Hungary), strata inclination follows gentle flanks of this antiform and similar is true for other sinforms and antiforms throughout the Mura-Zala Basin. Several very small collieries were in operation in the area of the Ormož-Selnica Antiform between the 1850s and 1970s. The only a little larger was the Mursko Središće colliery, with the highest production of 170,000 tonnes in 1965, and closed in 1972. Coal beds in the broader area of NE Slovenia (ca 1000 km2) are not explored enough. They were encountered by almost all deep oil, gas, and hydrogeological wells but these wells were not core-drilled. The existing data are originating only from master-logs and geophysical logs, by which, coal thicknesses are most probably exaggerated - telling us about thicknesses of single coal beds of 4 metres and even more. Therefore, realistically speaking, if analogy with the Lendava coal-bearing area is taken into consideration, and taking into account that the coal seams thicker than 1 m are in total 5 m thick, than the total coal resources (at the 1.3 t/m3 density) in the entire NE Slovenia amount to around 6500 Mt. In terms of energy, at calorific value of coal of 14.5 MJ/kg, it represents nearly 1014MJ of energy stored.

Modelling of groundwater flow in heterogeneous porous media by finite element method

AbstractThe HySuf‐FEM code (Hydrodynamic of Subsurface Flow by Finite Element Method) is proposed in this article in order to estimate the spatial variability of the transmissivity values of the Berrechid aquifer (Morocco).The calibration of the model is based on the hydraulic head, hydraulic conductivity and recharge. Three numerical tests are used to validate the model and verify its convergence. The first test case consists in using the steady analytical solution of the Poisson equation. In the second, the model has been compared with the hydrogeological system which is characterized by an unconfined monolayer (isotropic layer) and computed by using PMWIN‐MODFLOW software. The third test case is based on the comparison between the results of HySuf‐FEM and the multiple cell balance method in the aquifer system with natural boundaries case.Good agreement between the Hydrodynamic of Subsurface Flow, the numerical tests and the spatial distribution of the thickening of the hydrogeological system is deduced from the analysis and the interpretations of hydrogeological wells. Copyright © 2011 John Wiley & Sons, Ltd.

Characterization of the Cretaceous aquifer structure of the Meskala region of the Essaouira Basin, Morocco

The aquifer of early Cretaceous age in the Meskala region of the Essaouira Basin is defined by interpretation of geological drilling data of oil and hydrogeological wells, field measurement and analysis of in situ fracture orientations, and the application of a morphostructural method to identify lineaments. These analyzes are used to develop a stratigraphic–structural model of the aquifer delimited by fault zones of two principal orientations: NNE and WNW. These fault zones define fault blocks that range in area from 4 to 150 km 2. These blocks correspond either to elevated zones (horsts) or depressed zones (grabens). This structural setting with faults blocks of Meskala region is in accordance with the structure of the whole Essaouira Basin. Fault zones disrupt the continuity of the aquifer throughout the study area, create recharge and discharge zones, and create dip to the units from approximately 10° to near vertical in various orientations. Fracture measurements and morphometric-lineament analyzes help to identify unmapped faults, and represent features important to groundwater hydraulics and water quality within fault blocks. The above geologic features will enable a better understanding of the behaviour and hydro-geo-chemical and hydrodynamics of groundwater in the Meskala aquifer.

Une approche multicritères pour l'implantation de forages dans les zones productives des systèmes fissurés / A multicriteria approach for well drilling in productive zones of fissured systems

The multicriteria approach used in this paper aims to examine the aquifer of the Essaouira basin (Morocco). Investigation methods such as interpretation of hydrogeological wells and seismic sections, as well as the analysis of in situ fissuration measurements and field observations are used together in this study. The established hydrostructural models reveal the groundwater flow and the structure of the coastal aquifer system, whose heterogeneous hydrogeological formations contain very important water resources for the Moroccan coastal area. The partition of the Cretaceous Essaouira aquifer, and of its impermeable basement (Cenomanian marls) corresponds to a tectonic structure (horsts and grabens) resulting from reactivation of Hercynian structures. The identification of the normal faulting network demonstrates an influence of the structural geology on the specificity of coastal aquifers, on the groundwater flow, on the piezometric variation and the productivity of wells, depending on their location.

Origin of a fresh groundwater body in Cholistan, Thar Desert, Pakistan

Abstract The Thar Desert of Pakistan stretches along the border to India and is one of the most densely populated deserts in the world. Brackish to saline groundwater prevails. A locally restricted fresh groundwater resource was discovered by a comprehensive hydrogeological, geophysical, and isotope hydrological survey conducted from 1986 to 1991. The origin, recharge mechanism and age of the fresh groundwater resource were assessed. There is only fossil groundwater and this must be mined. Sodium is the predominant cation. Present groundwater recharge is absent or extremely low as the annual precipitation rate and the potential evapotranspiration rate amount to less than 200 mm/a and about 2700 mm/a, respectively. The investigations comprised a hydrogeological well inventory, electrical resistivity transects on the ground and an air-borne electromagnetic survey, followed by a test-hole drilling programme combined with geophysical borehole logging, aquifer testing, and groundwater sampling for both chemical and environmental isotope analyses. The results of this study delivered a hydrogeological concept on the origin and recharge of the fresh groundwater body. We found that the fresh groundwater was indirectly recharged during flash floods in low lands during the last pluvial period rather than directly replenished in the high mountain areas far in the east.

Investigation of microbial communities of Viluchinskaya hydrothermal system (Kamchatka) by methods of optical and electron microscopy

The hydrothermal systems of Kamchatka are unique natural laboratories where minerals are formed under the natural conditions at the present time. Elucidation of the role of bacteria, algae, and diatoms from thermal waters and bacterial mats in the geochemical transformation of rocks has attracted the special attention of researchers. The involvement of microorganisms in the processes of precipitation and formation of new mineral forms has been studied for a long time and has remained an essential piece of evidence for their active role in the functioning of thermal ecosystems [1]. In the present work, we studied certain characteristics of the waters of the Viluchinskaya hydrothermal system. We analyzed the chemical composition of the water, the total number of bacteria and the proportion of microorganisms in the aquatic microbial community that exhibited enzymatic activity. Actual evidence of the formation of amorphous precipitates of silicon, iron, and calcium on the surface of bacterial cells is also given. Water samples were collected in March and October, 2002 from hydrogeological wells nos. 1 and 2, located on the right bank of the Spokoinyi stream, from natural thermal outlets 1 and 2 of the travertine cupola and from the arsenical spring, located on the travertine terrace along the right bank of the Vilucha river. The physicochemical parameters of the water (water temperature, pH, and concentration of dissolved oxygen) were determined under field conditions. The chemical composition of the water was analyzed by methods of colorimetry, a combination of photometry and atomic absorption and atomic emission spectrophotometry, mass-spectrometry (ICP-MS), and X-ray fluorescence analysis. To assay the total number of bacteria (TNB), the samples were prepared as described earlier [2]. The numbers of bacteria exhibiting enzymatic activity (BEA) were determined with 5-carboxyfluorescein diacetate (CFDA); its intracellular decomposition by esterases results in the formation of a fluorochrome carboxyfluorescein. CFDA (Molecular Probes Inc.) was added directly during collection of thermal water samples up to the final concentration of 0.1 mM [3]. The samples of autoclaved thermal water served as a negative control. Cell counts were performed with an epifluorescent microscope (Nikon EFD-3; digital camera system: Nikon COOLPIX E995, Japan) equipped with a set of appropriate color filters at 100 × magnification. The average and the standard deviation were assayed by the results of cell counts in 10‐20 random microscope fields in all filters. The portion of EAB was expressed as a percentage of the TNB. The samples were prepared for scanning electron microscopy (SEM) by the method of cryophilic drying [4]. The samples were analyzed by the SEM equipped with energy spectrometer (SEM: JEOLJSM-5200LV; EDS: Philips-EDAX PV9800 STD, Japan). The grids for transmission microscopy were fastened on the slides with a carbonic suspension to assess the morphological diversity of microorganisms of thermal waters. The slides were incubated under the natural conditions for a day, fixed with 2.5% glutaric aldehyde, dried in the air, and analyzed with a JEOL 2000EX transmission microscope (Japan) at accelerating voltage 80‐120 kV. All samples were characterized by low concentrations of dissolved oxygen, which did not exceed 1.63 mg/ml (at well 1, the temperature 57°C ), and high temperatures ( 57–74°C ). All samples had pH values close to neutral (from 6.85 to 7.75). The waters varied

Spatial distribution of resistivity in the hydrogeological systems, and identification of the catchment area in the Rharb basin, Morocco / Répartition spatiale de la résistivité dans les systèmes hydrogéologiques et détection des zones de captages dans le bassin du Rharb, Maroc

Geophysical results obtained in the Rharb basin, Morocco are reported. Correlations between hydrogeological well logs reveal several water-bearing Plio-Quaternary units resting on a substrate of blue marls. Geo-electrical borehole analyses were interpreted using bi-logarithmic diagrams which indicate the permeable layers of the aquifer and also its basement. Resistivity data from NE–SW and NW–SE electrical sections allow definition of the permeable/impermeable levels, and identification of ȁditchesȁ that may be favourable sectors for hydrogeological exploitation. Resistivity anomalies were investigated by analysing maps of resistivity at 400 and 1000 m AB. Anomalies identified in the Rharb basin are related to the thickening of the permeable bodies (sand, limestone, sandstone deposits). In the coastal zone (AB = 1000 m), there is a strong decrease of the resistivity gradient (35–10 Ω m), which is probably linked to marine intrusion. Electrical anomalies allow detection of the water-bearing zones notably in the western and southwestern parts of the Rharb basin.

How to Compute the Permeability and Skin Factor of Low Pressure Water Zones

Abstract The paper presents a simple mathematical model which allows prediction of the behaviour of the water table in a low pressure water well which does not flow to surface. The derived relations enable computation of the permeability and skin factor of the water zone. Unlike the type-curve method used for interpretation of "slug test" data, the permeability and skin are computed using a straight-line approximation. The slope of the straight line and its intersection with the ordinate axis are used to interpret the test data. The presented method is very simple and yields unique results. How to Compute Permeability and Skin In low pressure water wells, the water table stabilizes at some depth below the surface. Such a situation is observed in water wells, some oil wells, hydrogeological wells and coalbed methane wells. "Slug testing"involves the sudden removal of some liquid from the well, and then analysing the water table behaviour (or pressure response) to determine the reservoir transmissibility. If the duration of flow from the reservoir is sufficiently long, liquid will continue to accumulate in the well until the pressure exerted by the liquid column in the well equals the reservoir pressure. The permeability and skin are evaluated by matching the measured pressure vs. time data or water level vs. time data to one curve among the family of theoretical curves. Mismatching ends up with erroneous results. The model presented here enables computation of the permeability and skin using a straight-line approximation through the conventional "slug test" data; i.e., it can be used for interpretation of DST flow period data. The relation (derived in the Appendix) used to compute the permeability and skin is: Equation (1) Available In Full Paper. z0 denotes the stabilized liquid level (which corresponds to original reservoir pressure), and z1 denotes the liquid level after some fluid is removed from the well at t = 0 (which corresponds to initial tubing pressure at the water zone level). z(t) is a current water level measured while the water table rises up in the well (corresponds to actual tubing pressure at the water zone level). The following nomenclature is assumed in Equation (1):k = permeability of a water zoneh = thickness of a water zoneρ = fluid densityg = acceleration of gravityr w = tubing radiust = timeφ = porosity of a water zoneμ = fluid viscosityS = skin factor Equation Available In Full Paper. is a root of the following equation: Equation (2) Available In Full Paper. Where Equation (3) Available In Full Paper. As long as ct does not change with time, Equation (1) indicates that a plot of Equation Available In Full Paper. vs. t is linear with slope Equation (4) Available In Full Paper. permitting the calculation of permeability, k. The skin factor can be calculated by evaluating the point of intersection of the same plot at t = 0, given as D: Equation (5) Available In Full Paper.

Hydrogeological Conditions of Submarine Groundwater Discharge in the Crimea

A structural hydrogeological model of the Crimea based on the assumption of the leading role of faults in groundwater distribution is discussed. Areas with intense submarine groundwater discharge are outlined. The existence of water streams related to the faults in the area of the Chernaya River, Mramornaya Gully, Varnautskaya Depression, Batiliman Bay, and Nikitskii Cape is substantiated. The sites for drilling hydrogeological wells are recommended.

Neutron-gamma well logging apparatus with more sensitivity for chlorine

A new neutron-gamma well logging apparatus for separating in the earth section of collection strata with poor mineralized water is described. In such a setting construction materials other than iron are used. The probing device (sonde) uses a Cf 252 neutron source and NaI(Tl) spectrometric detector. In conditions of a closed oil well in the optimum mineralization range (15–40 g chloride salt/l water) the difference in registrated data against poorly minearlized water with fresh fluid is more than 10% (in porosity 20%). The apparatus has an external strong frame with diameter of 90 mm. the maximum operating temperature is 120°C. The apparatus is designed for investigation of oil, gas, hydrogeological wells and ecological purposes.