Geology, Geophysics and Environment

Front page

2024-09-30

Editorial page

2024-09-30

Instruction for the authors

2024-09-30

Mapping a fracture network formed by hydraulic fracturing in a shale gas reservoir

Elżbieta Węglińska — 2024-06-21

Microseismic monitoring is an important technique that can be used to identify fractures in rock mass. The aim of this article is to identify, on the basis of the location of microseismic events, structures formed by hydraulic fracturing in the Wysin-2H/2Hbis horizontal well from the Baltic Basin in northern Poland, and to compare the patterns of these structures with the direction of regional stresses. The authors proposed a novel multi-step workflow for finding these structures. To be able to delineate the structures from microseismic events with greater accuracy, a collapsing algorithm was used. Then, based on the Hierarchical Density-Based Spatial Clustering of Applications with Noise (HDBSCAN) clustering algorithm and the elongation coefficient of each cluster, probable fissures were identified and compared against the maximum horizontal stress direction. In addition, based on the 3D seismic data from the Wysin and the calculated geomechanical parameters in the monitoring well, the probability classes of brittleness indices in the LMR (λρ-μρ) parameter domain were determined. A comparative analysis was performed between the two variants of microseismic event location (before and after the collapsing procedure) and the estimated probability of a given class of brittleness index. The comparison of the event location with the 3D seismic data was used to validate the results before and after collapsing due to the high resolution of the seismic method. It is shown that the collapsed events appeared in more rigid regions, where more energy release is expected.

Hydrochemical aspects of water exchange through the bottom of headwater stream in suburban zone on the example of the Malina watercourse in Zgierz (Central Poland)

Maciej Ziułkiewicz — 2024-09-02

Among the many factors determining the quality of river waters, the influence of the hyporheic zone (HZ) is gaining in importance. Watercourses that exist in the higher parts of catchments are relatively steep and shallow, and the topography of their valleys activate hyporheic flow. The main goal of this work is to assess the impact of the HZ on the hydrochemical state of the head watercourse of the Malina in the suburbs of the city of Zgierz with the focus on biogenic compounds. The riverbed of this stream was researched across two distinct stretches: erosive and accumulative, which differ in the conditions for the hyporheic zone’s interaction with the riverbed. The nutrients are delivered to the stream mainly in the erosive stretch and are related to the inflow of nutrient-rich groundwater from the urbanised catchment. The pollutants transported down by the stream are then delivered to the HZ in the accumulative stretch, where nitrates are denitrified and phosphates are deposited with the suspension. Ammonium nitrogen, in turn, is introduced into the stream from the HZ as a result of either the process of ammonification of organic matter deposited in sediments or inflow with polluted groundwater. The results indicate that the winter season is the most important period in shaping the interaction of river waters with the underlying hyporheic zone, in which the causal side of the relationship should be associated with the subchannel environment, and the effects are recorded in the river waters.

Complex and spatial analysis of geophysical data recorded in the areas of karst forms developed in horst structures

Tomisław Gołębiowski — 2024-09-30

The paper presents the results of geophysical surveys carried out over two voids occurring in limestone in the area of the Zakrzówek horst in Krakow, Poland. The first void was an anthropogenic cavern in the Kostrze site (a district of Krakow), while the second one was the Jasna cave (located in a reserve named “The Twardowski Rocks”). The main terrain surveys were carried out using GPR (ground penetrating radar). To reduce interpretative ambiguity, the GPR results were correlated with additional results obtained from two other methods, i.e. the GCM (ground conductivity meter) and ERT (electrical resistivity tomography). The main aim of the geophysical surveys was the detection and 3D visualisation of karst forms developed around both voids located in horst structures in limestone. The particular purpose of the research was to try to clarify the geological nature of the GPRnanomalies characterised by an almost complete lack of reflections; both ohmic and scattering attenuations of GPR signals were analysed to solve the reduction of the reflection amplitudes. Another important fact discussed in the paper was the low consistency and similarity of the results obtained from geophysical surveys carried out above the Jasna cave. The interpretation of the GPR and GCM data recorded over the anthropogenic cavern allowed the places of strong weathering/fracturing of limestone to be indicated as well as a zone of limestone filled with clay-rich material. The interpretation of the GPR and ERT data recorded over the cave made it possible to identify areas of the strong weathering/fracturing of limestone, faults, anastomoses and karst chimneys.

Geothermal energy potential of Main Dolomite formation in SW Poland

Małgorzata Słota-Valim — 2024-09-30

This paper evaluates the geothermal potential of the Main Dolomite formation in an oil and gas field on the Fore-Sudetic Monocline (SW, Poland). The reservoir characterization included a well-logging interpretation and developed 3D petrophysical and temperature models that provided information on storage potential, transport properties, and temperature conditions in the analyzed carbonate formation. Geothermal energy potential was assessed using heat in place (HIP) and recoverable heat (Hrec) parameters for water and CO₂systems, considering a 50-year plant lifespan. Petrophysical and temperature data classify reservoirs using unsupervised machine learning, identifying zones with high and low geothermal potential, noting a strong limestone and dolomite dichotomy. Dolomite horizon shows more promising reservoir quality with mean porosity and permeability of 0.045 and 0.4 mD, respectively, however, its mean thickness reaches 11.58 m at maximum. The calculated Hrec for a 50-year lifetime of a geothermal system varies across dolomite horizon. In the most promising areas of NNW, WSW, and E parts, the values of Hrec are 8.19, 3.47, and 1.34 MW for water, respectively, and 0.69, 0.29, and 0.11 MW for CO₂as working fluids. Remarkably, the energy locked in the NNW zone constitutes nearly 21% of the total geothermal energy potential within the entire dolomite horizons of the study area. The geothermal resources for the most perspective location within the dolomite horizon were estimated at 12.99 and 1.09 MW levels, using water and CO₂ as working fluids, respectively, assuming 50 years of the project’s lifetime.

The usability of the Nash cascade-submerged cascade rainfall-runoff model with regard to other conceptual models

Norbert Laskowski — 2024-09-26

Conceptual hydrological models are an effective tool used to forecast runoff from catchments and assess changes in catchment dynamics. The article presents a modified concept of the Diskin parallel cascade model, with the replacement of one of the cascades with the submerged cascade model – the Nash cascade-submerged cascade model (NCSC2). Considering a watershed as a system where total runoff is determined by amounts of both surface and subsurface runoffs, the use of different model structures as surface and subsurface runoffs is reasonable. Adopting 13 different objective functions, the comparative analysis of NCSC2, Nash cascade, Diskin model, single linear reservoir and submerged reservoir cascade (SC2) models has been carried out in the catchment of six Polish rivers. The research has shown that the use of the submerged cascade as one of the Diskin model cascades positively affects the quality of the model.

Radiological analysis of food products of forest origin in the pollution zone of the Kamin-Kashyrskyi district of the Volyn region of Ukraine

Oksana Hromyk — 2024-09-30

The problem of the radiological contamination of food products from secondary forest use remains relevant and requires targeted preventive measures, with the contamination being the result of the Chornobyl nuclear power plant disaster. The research was conducted with the aim of comprehensively monitoring the content of radionuclide ¹³⁷Cs in forest products (Wild Bilberry (Vaccinium myrtillus), Blackberries (Rubus L.), Wild Strawberries (Fragaria vesca L.), Raspberry (Rubus idaeus L.), together with Cantharellus cibarius, Boletus edulis, and Leccinum scabrum mushrooms) of the zone of radioactive contamination of the Kamin-Kashyrskyi district of the Volyn region. Samples were collected in 2020–2022. The total number of samples was 729 dried and 975 fresh mushrooms and berries samples for 2020, 1,154 dried and 886 fresh samples for 2021, and 870 dried and 896 fresh samples for 2022. The results of research indicate that in the specified territory, and at the present moment, forest products are to be found with a significant content of the radionuclide ¹³⁷Cs, including those exceeding the permissible levels. There is, therefore, a threat of further internal exposure of the local population via access to procurement points of contaminated products and restaurants. In connection with the detection of these pollutants in forest products in the studied area, further expansion of specialized radioecological monitoring studies and strengthening of radiological control remains relevant.

Geology, Geophysics and Environment

Front page

Editorial page

Table of contents

Instruction for the authors

Mapping a fracture network formed by hydraulic fracturing in a shale gas reservoir

Hydrochemical aspects of water exchange through the bottom of headwater stream in suburban zone on the example of the Malina watercourse in Zgierz (Central Poland)

Complex and spatial analysis of geophysical data recorded in the areas of karst forms developed in horst structures

Geothermal energy potential of Main Dolomite formation in SW Poland

The usability of the Nash cascade-submerged cascade rainfall-runoff model with regard to other conceptual models

Radiological analysis of food products of forest origin in the pollution zone of the Kamin-Kashyrskyi district of the Volyn region of Ukraine