@article{MTMT:34850604,
	title = {Continuous wavelet transformation to quantify small-scale cycles of petrophysical properties; a new approach applied in a potential disposal repository of nuclear waste, SW Hungary},
	url = {https://m2.mtmt.hu/api/publication/34850604},
	author = {Abutaha, Saja and Geiger, János and Fedor, Ferenc and Gulyás, Sándor},
	journal-iso = {GEOL CROAT},
	journal = {GEOLOGIA CROATICA},
	volume = {76},
	unique-id = {34850604},
	issn = {1330-030X},
	abstract = {Continuous Wavelet Transformation (CWT) was applied to study the small-scale repetitive oscillations of porosity distribution patterns in a 5 m silty-claystone core sample of the Boda Claystone Formation. We handled the fluctuations in voxel porosity averages over unequal depth distributions as signals over uneven time intervals. The strength of wavelet analysis lies in the ability to study the fluctuation of a signal in detail, i.e., the wavelet transforms permit automatic localization of the cyclic attributes' sequences both in time (the depth domain) and according to their frequency (the frequency domain). Thereupon, three main frequency branches (cycles) were discerned: small scale (5, 6.67, and 11 cm), intermediate scale (20, 30 cm), and large scale (66.67 cm). Depending on the CWT coefficients magnitude plot, we were able to detect the developments of porosity oscillation according to the depth variable. Thus, small-scale cycles were seen throughout the core sample., the intermediate-scale cycles were strong in the upper parts of the core sample and dwindled toward greater depths, and the large cycle was predominant in the lower part of the core sample. The cross-correlation of the wavelet coefficients of porosity and rock-forming components allows a detailed study of the inter-dependence of such parameters as their relationship changes over time. The distinct peaks at zero lag indicates that the measured wavelet coefficient series were contemporaneously correlated; their strong positive correlations suggest that both examined series respond similarly and simultaneously to other exogenous factors. The results emphasize that cyclical porosity fluctuations at all scales would concern three main factors; sediment deposition, diagenetic processes, and structural deformation (i.e., convolute laminations).},
	year = {2023},
	eissn = {1333-4875},
	pages = {131-146},
	orcid-numbers = {Abutaha, Saja/0000-0001-8439-5895; Geiger, János/0000-0001-9359-5266; Gulyás, Sándor/0000-0002-3384-2381}
}

@article{MTMT:34053442,
	title = {Semi-analytical approach to the determination of fracture permeability},
	url = {https://m2.mtmt.hu/api/publication/34053442},
	author = {Pusztai, Patrik and Koroncz, Péter János and Kuncz, Máté and Jobbik, Anita and Fedor, Ferenc},
	doi = {10.1007/s13137-023-00227-8},
	journal-iso = {GEM - INT J GEOMATHEMATICS},
	journal = {GEM - INTERNATIONAL JOURNAL ON GEOMATHEMATICS},
	volume = {14},
	unique-id = {34053442},
	issn = {1869-2672},
	abstract = {Proppant is one of the major elements of a hydraulic fracture process that can influence the productivity of an oil or gas well. The permeability of a propped fracture may be determined through laboratory measurements, utilizing experimental relationships, or using analytical methods. All methods have their advantages and disadvantages, and this study attempts to offers a solution that combines the various methods to achieve a practical solution. The standard measurement method for fracture conductivity and permeability is a time-consuming and delicate procedure and can be performed only at the cost of a significant degree of uncertainty. Investigating a method that can predict fracture permeability in significantly less time and with an acceptable level of accuracy would be useful for the industry. Proppant can be viewed as an unconsolidated, heterogeneous (in size distribution) although well-sorted granular packing, and the different relationships that can predict the permeability of such systems may be utilized. Such interdependencies account for the frictional pressure drop caused by the proppant particles and often neglect the pressure drop caused by the surface of the apparatus. To extend the applicability of the various models, the combination of a theoretical model that accounts for the pressure drop caused by the fracture wall with those models would have clear practical advantages. For this reason, a new equation had to be developed that establishes the relationship between the fracture permeability and the so-called modified particle friction factor. Since the frictional pressure drop correlations usually contain porosity as a parameter, determining its value under reservoir conditions is essential and a new procedure had to be developed. Since the different relationships were developed under different conditions to those under which the proppant-packs are usually used, providing a solution to the issues of their wide range of application is the primary objective of this study.},
	keywords = {FRACTURE; Permeability; Oil and gas well},
	year = {2023},
	eissn = {1869-2680},
	orcid-numbers = {Pusztai, Patrik/0000-0003-3090-9840}
}

@inproceedings{MTMT:34068417,
	title = {A 8. Nemzetközi Agyag Konferencia (Nancy) tapasztalatai, a kutatás fókusza},
	url = {https://m2.mtmt.hu/api/publication/34068417},
	author = {Kuncz, Máté and Ács, Péter and Fedor, Ferenc},
	booktitle = {Bodai Agyagkő Formáció (BAF) kutatásának legújabb eredményei},
	unique-id = {34068417},
	year = {2022},
	pages = {65-72}
}

@article{MTMT:33296781,
	title = {Experimental Rock Characterisation of Upper Pannonian Sandstones from Szentes Geothermal Field, Hungary},
	url = {https://m2.mtmt.hu/api/publication/33296781},
	author = {Koroncz, Péter János and Vizhányó, Zsanett and Farkas, Márton Pál and Kuncz, Máté and Ács, Péter and Kocsis, Gábor and Mucsi, Péter and Fedorné Szász, Anita and Fedor, Ferenc and Kovács, János},
	doi = {10.3390/en15239136},
	journal-iso = {ENERGIES},
	journal = {ENERGIES},
	volume = {15},
	unique-id = {33296781},
	issn = {1996-1073},
	abstract = {The Upper Pannonian (UP) sandstone formation has been utilised for thermal water production in Hungary for several decades. Although sustainable utilisation requires the reinjection of cooled geothermal brine into the host rock, only a fraction of the used water is reinjected in the country. UP sandstone formation is reported to exhibit low injectivity, making reinjection challenging, and its petrophysical properties are poorly known, which increases uncertainty in designing operational parameters. The goal of the study is to provide experimental data and to gain a better understanding of formation characteristics that control injectivity and productivity issues in Upper Pannonian sandstone layers. Petrographical characterisation and petrophysical laboratory experiments are conducted on cores retrieved from two wells drilled in the framework of an R&D project at the depth of between 1750 m and 2000 m. The experiments, such as grain density, porosity, permeability, and ultrasonic velocity, as well as thin section, grain size distribution, XRD, and SEM analyses, are used to determine Petrophysical Rock Types (PRT) that share distinct hydraulic (flow zone indicator, FZI) and petrophysical characteristics. These are used to identify well intervals with lower potential for injectivity issues. The results imply that fines migration due to formation erosion is one of the key processes that must be better understood and controlled in order to mitigate injectivity issues at the study area. Future investigation should include numerical and experimental characterisation of formation damage, including water–rock interaction tests, critical flow velocity measurements, and fines migration analysis under reservoir conditions.},
	year = {2022},
	eissn = {1996-1073},
	orcid-numbers = {Kovács, János/0000-0001-7742-5515}
}

@article{MTMT:32928316,
	title = {Calculating the representative elementary volume of porosity using X-ray computed tomography: Boda Claystone Formation core sample/Hungary},
	url = {https://m2.mtmt.hu/api/publication/32928316},
	author = {Abutaha, Saja and Geiger, János and Gulyás, Sándor and Fedor, Ferenc},
	journal-iso = {ACTA GEOL SLOV},
	journal = {ACTA GEOLOGICA SLOVACA},
	volume = {14},
	unique-id = {32928316},
	issn = {1338-0044},
	year = {2022},
	eissn = {1338-5674},
	pages = {25-36},
	orcid-numbers = {Abutaha, Saja/0000-0001-8439-5895; Geiger, János/0000-0001-9359-5266; Gulyás, Sándor/0000-0002-3384-2381}
}

@misc{MTMT:32863782,
	title = {Geomates 2022},
	url = {https://m2.mtmt.hu/api/publication/32863782},
	author = {Fedor, Ferenc and Hatvani, István Gábor},
	unique-id = {32863782},
	year = {2022},
	orcid-numbers = {Hatvani, István Gábor/0000-0002-9262-7315}
}

@misc{MTMT:32841899,
	title = {22. Geomatematikai Kongresszus. konferencia összefoglaló},
	url = {https://m2.mtmt.hu/api/publication/32841899},
	author = {Fedor, Ferenc},
	unique-id = {32841899},
	year = {2022}
}

@article{MTMT:32838330,
	title = {GeoMATES 2022},
	url = {https://m2.mtmt.hu/api/publication/32838330},
	author = {Fedor, Ferenc and Hatvani, István Gábor},
	journal-iso = {DÉL-DUNÁNTÚLI GAZDASÁG},
	journal = {DÉL-DUNÁNTÚLI GAZDASÁG: A PÉCS - BARANYAI KERESKEDELMI ÉS IPARKAMARA LAPJA},
	volume = {24},
	unique-id = {32838330},
	issn = {1419-8746},
	year = {2022},
	pages = {23-23},
	orcid-numbers = {Hatvani, István Gábor/0000-0002-9262-7315}
}

@book{MTMT:32817365,
	title = {GeoMATES '22 International Congress on Geomathematics in Earth- and Environmental Sciences. the 22nd Congress of Hungarian Geomathematicians},
	url = {https://m2.mtmt.hu/api/publication/32817365},
	isbn = {9789637068140},
	editor = {Hatvani, István Gábor and Erdélyi, Dániel and Fedor, Ferenc},
	publisher = {MTA Pécsi Területi Bizottság},
	unique-id = {32817365},
	year = {2022},
	orcid-numbers = {Hatvani, István Gábor/0000-0002-9262-7315}
}

@CONFERENCE{MTMT:32607491,
	title = {Is proppant embedment a real phenomenon in the case of Upper Pannonian unconsolidated and friable sands?},
	url = {https://m2.mtmt.hu/api/publication/32607491},
	author = {Koroncz, P. J. and Fedorné Szász, A. and Fedor, Ferenc and Kovács, János},
	booktitle = {International Symposium on Geofluids Abstract Volume},
	unique-id = {32607491},
	year = {2021},
	pages = {94},
	orcid-numbers = {Kovács, János/0000-0001-7742-5515}
}