Péter Szűcs

Factor analysis of borehole logs for evaluating formation shaliness: a hydrogeophysical application for groundwater studies

The calculation of groundwater reserves in shaly sand aquifers requires a reliable estimation of effective porosity and permeability; the amount of shaliness as a related quantity can be determined from well log analysis. The conventionally used linear model, connecting the natural gamma-ray index to shale content, often gives only a rough estimate of shale volume. A non-linear model is suggested, which is derived from the factor analysis of well-logging data. An earlier study of hydrocarbon wells revealed an empirical relationship between the factor scores and shale volume, independent of the well site. Borehole logs from three groundwater wells drilled in the northeastern Great Hungarian Plain are analyzed to derive depth logs of factor variables, which are then correlated with shale volumes given from the method of Larionov. Shale volume logs derived by the statistical procedure are in close agreement with those derived from Larionov’s formula, which confirms the validity of the non-linear approximation. The statistical results are in good accordance with laboratory measurements made on core samples. Whereas conventional methods normally use a single well log as input, factor analysis processes all available logs to provide groundwater exploration with reliable estimations of shale volume.RésuméLe calcul de réserves d’eau souterraine dans des aquifères sablo-argileux nécessite une estimation fiable de la porosité efficace et de la perméabilité; la quantité d’argilosité comme paramètre relatif peut être déterminée à partir de l’analyse des logs de forage. Le modèle linéaire communément utilisé, associant l’index d’émission gamma à la teneur en argiles donne souvent une estimation grossière du volume d’argiles. Un modèle non linéaire est suggéré, qui est dérivé de l’analyse factorielle des données de logs de forages. Une étude antérieure de forages pour hydrocarbures avait révélé une relation empirique entre les scores de l’analyse factorielle et le volume d’argiles, indépendamment de l’emplacement du forage. Les logs des trois forages d’eau exécutés au Nord Est de la Grande Plaine Hongroise sont analysés pour déduire les variables des logs pour l’analyse factorielle, qui sont ensuite corrélées avec le volume d’argiles donné par la méthode de Larionov. Les logs de volume d’argiles dérivés de la procédure statistique sont en accord étroit avec ceux dérivés de la formule de Larionov, ce qui confirme la validité de l’approximation non linéaire. Les résultats statistiques sont en bon accord avec les mesures de laboratoire faites sur des carottes. Alors que les méthodes conventionnelles utilisent normalement le log unique d’un forage comme entrée, l’analyse factorielle considère tous les logs disponibles pour fournir une exploration des aquifères avec une estimation fiable du volume des argiles.ResumenEl cálculo de las reservas de agua subterránea en acuíferos de arenas arcillosas requiere una estimación confiable de la porosidad eficaz y de la permeabilidad; la magnitud de la arcillosidad como una cantidad relacionada puede ser determinada a partir de análisis de registros de pozos. El modelo lineal convencionalmente usado, que conecta el índice de rayos gamma natural con el contenido de arcilla, a menudo da sólo una estimación grosera del volumen de arcilla. Se sugiere un modelo no lineal, desarrollado del análisis factorial a partir de datos de registros de pozos. Un estudio anterior de pozos hidrocarburíferos reveló una relación empírica entre los factores determinantes y el volumen de arcilla, independiente de la localización del pozo. Se analizaron los registros de de tres pozos de agua subterránea perforados en el noreste de la planicie Great Hungarian para deducir los registros en profundidad de los factores determinantes, los cuales fueron luego correlacionados con los volúmenes de arcilla dados a partir del método de Larionov. Los registros del volumen de arcilla deducidos por el procedimiento estadístico están en cercana coincidencia con aquellos derivados de la fórmula de Larionov’s, lo cual confirma la validez de la aproximación no lineal. Los resultados estadísticos están en un buen acuerdo con las mediciones de laboratorio hechas sobre muestras testigos. Mientras que los métodos convencionales normalmente usan un solo registro de pozo como entrada, el análisis factorial procesa todos los registros disponibles para proveer a la exploración de agua subterránea con estimaciones confiables del volumen de arcilla.KivonatAz agyagos homok tárolók édesvíz-készletének számítása az effektív porozitás és a permeábilitás megbízható becslését igényli; a karotázs szelvények kiértékeléséből meghatározható az agyagtartalom, mint ehhez kapcsolódó mennyiség. A hagyományosan alkalmazott lineáris modell, mely a természetes gamma indexhez köti az agyagtartalmat, gyakran csak durva becslés ad. A cikkben egy nemlineáris modellt javaslunk, amely mélyfúrási geofizikai szelvények faktoranalíziséből származik. Egy korábbi, szénhidrogén-kutató fúrásban történő alkalmazás terület-független tapasztalati összefüggést mutatott a faktor értékek és az agyagtartalom között. Jelen cikkben az Alföld észak-keleti részén fúrt három vízkutató fúrás szelvényeit dolgozzuk fel, abból származtatjuk a faktorok mélységszelvényeit, majd azokat a Larionov módszerrel kapott agyagtartalom szelvényekkel hasonlítjuk össze. A statisztikai módszerrel kapott agyagtartalmak jó egyezést mutatnak a Larionov egyenlettel számítottakkal, amely megerősíti a nemlineáris közelítés érvényességet. A statisztikai eredmények jó összhangban állnak magmintákon végzett laboratóriumi mérések eredményeivel. Míg a hagyományos módszerek általában egyetlen fúrólyuk szelvényt használnak fel bemeneti adatként, addig a faktoranalízis az összes rendelkezésre álló szelvényt feldolgozza, mellyel a vízkutatás számára megbízható agyagtartalom becslés valósítható meg.ResumoO cálculo das reservas de água subterrânea em aquíferos de areia argilosa requere uma estimação fiável da porosidade efetiva e da permeabilidade; e do teor de argilas, como uma quantidade relativa pode ser determinada a partir da análise de testemunhos de sondagem. O modelo linear convencional usado, correlacionando o índice de raio-gama natural com o conteúdo de argila, dá muitas vezes apenas uma estimativa grosseira do volume de argilas. É sugerido um modelo não linear, derivado do fator de análise dos dados dos testemunhos de sondagem. Um estudo anterior de furos de hidrocarbonetos revelou uma relação empírica entre os resultados fatoriais e o volume de argilas, independentemente dos locais dos furos. São analisados os testemunhos de sondagem de três furos de água subterrânea perfurados no nordeste da Grande Planície Húngara, a fim de obter perfis de profundidade das variáveis fatoriais, os quais são depois correlacionados com os volumes de argila dados pelo método de Larionov. O volume de argilas obtido por procedimento estatístico está de acordo com os obtidos a partir da fórmula de Larionov, a qual confirma a validade da aproximação não linear. Os resultados estatísticos encontram-se de acordo com as medições de laboratório feitas em amostras de testemunhos. Enquanto os métodos convencionais usam normalmente um furo simples como entrada, a análise fatorial processa todos os testemunhos disponíveis, a fim de providenciar a exploração de águas subterrâneas com estimações mais fiáveis sobre o volume de argilas.

Sustainability aspects of thermal water production in the region of Hajdúszoboszló-Debrecen, Hungary

Abstract As geothermal energy usage becomes more conspicuous the long-term effects of thermal water extraction become more significant. The greatest extent of exploitation in East Hungary occurs in the area of Hajdúszoboszló and Debrecen. The extracted thermal water is utilized mainly by their baths. In this paper, the sustainability of this system was examined with a steady state hydrodynamic model. The solid model is based on sequence stratigraphic interpretation while the hydraulic conductivity values were estimated based on the values of geophysical well-logs. The closely spaced wells cause a great subregional decrease of hydraulic head, particularly in the most intensively extracted layer, i.e. the layer of the delta front facies. The effects of extraction by the two spatial groups of wells intersect resulting in decreased profitability of subsequent wells. However, rationalizing thermal water utilization using water from shallower zones simultaneously may have beneficial effects on the yield distribution among the different layers.

Geoelectric Characterization of Thermal Water Aquifers Using 2.5D Inversion of VES Measurements

This paper presents a short theoretical summary of the series expansion-based 2.5D combined geoelectric weighted inversion (CGWI) method and highlights the advantageous way with which the number of unknowns can be decreased due to the simultaneous characteristic of this inversion. 2.5D CGWI is an approximate inversion method for the determination of 3D structures, which uses the joint 2D forward modeling of dip and strike direction data. In the inversion procedure, the Steiner’s most frequent value method is applied to the automatic separation of dip and strike direction data and outliers. The workflow of inversion and its practical application are presented in the study. For conventional vertical electrical sounding (VES) measurements, this method can determine the parameters of complex structures more accurately than the single inversion method. Field data show that the 2.5D CGWI which was developed can determine the optimal location for drilling an exploratory thermal water prospecting well. The novelty of this research is that the measured VES data in dip and strike direction are jointly inverted by the 2.5D CGWI method.

On the Reduced Noise Sensitivity of a New Fourier Transformation Algorithm

In this study, a new inversion method is presented for performing one-dimensional Fourier transform, which shows highly robust behavior against noises. As the Fourier transformation is linear, the data noise is also transformed to the frequency domain making the operation noise sensitive especially in case of non-Gaussian noise distribution. In the field of inverse problem theory it is well known that there are numerous procedures for noise rejection, so if the Fourier transformation is formulated as an inverse problem these tools can be used to reduce the noise sensitivity. It was demonstrated in many case studies that the method of most frequent value provides useful weights to increase the noise rejection capability of geophysical inversion methods. Following the basis of the latter method the Fourier transform is formulated as an iteratively reweighted least squares problem using Steiner’s weights. Series expansion was applied to the discretization of the continuous functions of the complex spectrum. It is shown that the Jacobian matrix of the inverse problem can be calculated as the inverse Fourier transform of the basis functions used in the series expansion. To avoid the calculation of the complex integral a set of basis functions being eigenfunctions of the inverse Fourier transform is produced. This procedure leads to the modified Hermite functions and results in quick and robust inversion-based Fourier transformation method. The numerical tests of the procedure show that the noise sensitivity can be reduced around an order of magnitude compared to the traditional discrete Fourier transform.

Examination of rainfall data for 110 years using spectral and wavelet analysis

The aim of our research was to better understand the spectral characteristics of precipitation variability, because through infiltration, this is the most important source of groundwater recharge. ...

Novel environmental management application for lignite

Mining and mineral processing operations are usually generating huge amount of tailings. These tailings often gives lots of maintenance work in order to protect environmental resources from heavy metals slowly leaching out of tailing are due to Acid Rock Drainage (ARD) process. Handling leakage could be active or passive such as using of Permeable Reactive Barriers (PRB). Using PRB technology water is not extracted, however PRB’s are built underground in the way of underground waters where contaminants are extracted or conversed into harmless components on the surface of the PRB matrix material (Madarasz, Toth, 2010). One of the most important criteria for using PRB to select or design the proper material for matrix material on which the contaminant adsorbs, precipitate or degrade. Water is able to going through the barrier and on the downstream side, clarified water is going to be released PRB’s are used worldwide treating underground contaminations, using different type of matrix materials. All generally used matrix material has its advantages and disadvantages such as selectivity, sensitivity of precipitation generation or not satisfying hydraulic conductivity. Nowadays cheap and effective matrix material which is ignorant to pore plugging caused by precipitation within the PRB could be one solution to the demands of the industry. The authors have been carried out an investigation at University of Miskolc on lignite as high humid acid containing material for determining the ability of heavy metal adsorption and pore plugging resistance. Moreover, using hydraulic and chemical simulation methods, complete PRB dimensioning protocol based on new lignite matrix had been introduced. Adsorption capacity of tested lignite samples were determined for toxic transient and heavy metal cations. Static and dynamic adsorption tests had been carried out parallel in order to investigate adsorption kinetics, while hydrodynamic and transport modelling also had been done. As a result of the research, a complex design protocol for lignite based PRB system had been established of which are being discussed within the frame of this paper.

Recent trends and activities in hydrogeologic research at the University of Miskolc, Hungary

The Institute of Environmental Management at the University of Miskolc, as a major Hungarian research entity in groundwater management, is dedicated to finding solutions to regional issues of global sustainable water resource management challenges, thus further developing its scope of groundwater management competence. WELLaHEAD is an EU-funded fundamental research program coordinated by the faculty members of the institute, covering a broad spectrum of relevant groundwater related research topics based on Northern Hungarian test sites. The research concept is described in the detailed Research Plan of the project, and after 14 project months some of intermediate results can be presented from three research modules.