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1

Magnetic inversion approach for modeling data acquired across faults: various environmental cases studies

Essa Khalid S., Abo-Ezz Eid R., Anderson N. L., Gomaa Omar A., Elhussein Mahmoud

Acta Geophysica

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2024

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Vol. 72, no. 3

1819--1845

EN

An effective extension to the particle swarm optimizer scheme has been developed to visualize and modelize robustly magnetic data acquired across vertical or dipping faults. This method can be applied to magnetic data sets that support various investigations, including mining, fault hazards assessment, and hydrocarbon exploration. The inversion algorithm is established depending on the second horizontal derivative technique and the particle swarm optimizer algorithm and was utilized for multi-source models. Herein, the inversion method is applied to three synthetic models (a dipping fault model contaminated without and with different Gaussian noises levels, a dipping fault model affected by regional anomaly, and a multi-source model) and three real datasets from India, Australia, and Egypt, respectively. The output models confirm the inversion approach’s accuracy, applicability, and efficacy. Also, the results obtained from the suggested approach have been correlated with those from other methods published in the literature.

2

Analysis of the stator current prediction capabilities in induction motor drive using the LSTM network

Teler Krystian, Orlowska-Kowalska Teresa

Power Electronics and Drives

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2023

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Vol. 8 (43)

31-52

EN

In modern areas of knowledge related to electric drive automation, there is often a need to predict the state variables of the drive system state variables, such as phase current and voltage, electromagnetic torque, stator and rotor flux, and others. This need arises mainly from the use of predictive control algorithms but also from the need to monitor the state of the drive to diagnose possible faults that have not yet occurred but may occur in the future. This paper presents a method for predicting stator phase current signals using a network composed of long-short-term memory units, allowing the simultaneous prediction of two signals. The developed network was trained on a set of current signals generated by software. Its operation was verified by simulation tests in a direct rotor flux-oriented control (DRFOC) structure for an induction motor drive in the Matlab/Simulink environment. An important property of this method is the possibility of obtaining a filtering action on the output of the network, whose intensity can be controlled by varying the sampling frequency of the training signals.

3

Fault detection in photovoltaic systems using the inverse of the belonging individual Gaussian probability

Sendjasni Salah, Yagoubi Benabdellah, Daoud Mohamed, Belbachir Nasreddine, Ziane Abderrezzaq

Diagnostyka

|

2023

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Vol. 24, No. 1

art. no. 2023112

EN

This article addresses the problem of fault early detection in photovoltaic systems. In the production field, solar power plants consist of many photovoltaic arrays, which may suffer from many different types of malfunctions over time. Hence, fault early detection before it affects PV systems and leads to a full system failure is essential to monitor these systems. The fields of control and monitoring of systems have been extensively approached by many researchers using various fault detection methods. Despite all this research, to early detect and locate faults in a very large photovoltaic power plant, we must, in particular, think of an effective method that allows us to do so at the lowest costs and time. Thus, we propose a new robust technique based on the inverse of the belonging individual Gaussian probability (IBIGP) to early detect and locate faults in the power curve as well as in the Infrared image of the photovoltaic systems. While most fault detection methods are well incorporated in other domains, the IBIGP technique is still in its infancy in the photovoltaic field. We will show, however, in this work that the IBIGP technique is a very promising tool for fault early detection enhancement.

4

Analysis and effect of static eccentricity fault on performance indicators of a synchronous reluctance motor

Idoko Emmanuel, Umoh Gideon David, Obe Pauline Ijeoma, Mama Benjamin Okwudili, Obe Emeka Simon

Archives of Electrical Engineering

|

2023

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Vol. 72, nr 3

829--848

EN

Fault diagnosis and condition monitoring of synchronous machines running under load is a key determinant of their lifespan and performance. Faults such as broken rotor bars, bent shafts and bearing issues lead to eccentricity faults. These faults if not monitored may lead to repair, replacement and unforeseen loss of income. Researchers who attempted to investigate this kind of machine stopped at characterizing and deduced ways, types and effects of rotor eccentricity fault on the machine inductances using the winding function method. A modified closed-form analytical model of an eccentric synchronus reluctance motor (SynRM) is developed here taking into cognizance the machine dimensions and winding distribution for the cases of a healthy and unhealthy SynRM. This paper reports the study the SynRM under static rotor eccentricity using the developed analytical model and firming up the model with finite element method (FEM) solutions. These methods are beneficial as they investigated and presented the influence of the degrees of static eccentricity on the machine performance indicators such as speed, torque and the stator current and assess the extent to which the machine performance will deteriorate when running with and without load. The results show that static eccentricity significantly affects the machine’s performance as the degree of eccentricity increases.

5

Verification of the deposit model and determining the course of the fault in the entire rock mass

Sokoła-Szewioła Violetta, Poniewiera Marian

Zeszyty Naukowe Akademii Morskiej w Szczecinie

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2022

|

nr 72 (144)

95--101

EN

This article presents results for the development of new methods of inserting discontinuity lines into the numerical model of the deposit in CAD systems. The main problem in creating a numerical model of the deposit is usually a very small number, as well as low reliability of the source data. Hence, the authors developed new algorithms for inputting discontinuities, which can be used in particular for conditions when a large number of discontinuities are present. The article offers algorithms for inputting discontinuities into the entire deposit model. The method of transferring faults from the higher seam to subsequent seams and determining the course of the fault in the entire rock mass has been described. The fault can be represented as a spatial mesh of triangles, just like the seam floor. Then the fault can be extended until it intersects with the next seam (with the next triangle mesh) using geostatistical methods. As a result, we determine the exact position of the discontinuity line in the next seam. The paper also presents several algorithms for checking the deposit model made using the methods developed by the authors, including the analysis of outliers (in terms of elevation and inclination), testing the variability of the fault throw, checking the distance between adjacent seams, and verifying the position of the deposit in relation to the existing workings and boreholes. It should be noted that the key issue while building a deposit model is a checking of the model, removal of the assumptions and, obviously, incorrect data in order to obtain the highest possible accuracy.

6

Methods of introducing a discontinuity line into a numerical model of a hard coal deposit

Sokoła-Szewioła Violetta, Poniewiera Marian

Zeszyty Naukowe Akademii Morskiej w Szczecinie

|

2022

|

nr 71 (143)

81--89

EN

The largest problem that we encounter when creating a numerical model of a hard coal deposit is to insert discontinuity lines representing faults, seams junction lines, wedging, etc. The faults introduced on the map of the seam are mostly flat polylines, while we do not know the altitude ordinate. In order to determine the spatial position of the faults, authoring methods have been developed and implemented in the Geolisp software and in the CAD system. This article presents the method based on calculating the spatial position of the fault with respect to the existing contours, which arrive at it from both sides, the method based on the assumption that the inclination of the seam in front of and behind the fault is constant, the procedure involving the performing of independent surfaces of the upthrow and downthrow side with extrapolation by the Kriging method, and the procedure requiring the transfer of the fault from the above-lying seam or a Carboniferous roof. The solutions given in the article are successfully used in most mines in Poland. The correct introduction of the fault course is important for the accuracy of forecasting the impact of the mining operations on the rock mass and the surface area.

7

Tectonic pulse registered between 2013 and 2015 on the eastern margin of the Bohemian Massif

Briestenský Miloš, Stemberk Josef, Littva Juraj, Vojtko Rastislav

Geological Quarterly

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2021

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Vol. 65, No. 1

art. no. 14

EN

A significant period of increased tectonics was monitored between 2013 and 2015 on the eastern margin of the Bohemian Massif along ten faults. Nine of them showed a uniform scheme: dextral strike-slip along generally NW–SE striking faults, sinistral strike-slip along generally NE-SW striking faults and uprising of the southern blocks. The distinguished fault displacements displayed an NNW-SSE striking compressional component of the stress field during this remarkable tectonic episode.

8

Kryteria oceny stanu technicznego budynków i budowli

Kupniewski Krzysztof

Budownictwo i Prawo

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2021

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R. 24, nr 4

15--18

PL

Firmy budowlane wprowadzają nowe technologie, systemy i materiały stosowane przy realizacji nowoczesnych budynków mieszkalnych, usługowych, biurowych, które wymagają nowego podejścia do oceny stanu technicznego obiektów o tak różnej konstrukcji.

EN

Construction companies introduce new technologies, systems and materials used in the construction of modern residential, service and office buildings, which require a new approach to the assessment of the technical condition of facilities of such a different structure.

9

Sliding mode observers for fault identification in linear systems not satisfying matching and minimum phase conditions

Zhirabok Alexey, Zuev Alexander, Filaretov Vladimir, Shumsky Alexey

Archives of Control Sciences

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2021

|

Vol. 31, No. 2

253--266

EN

The paper studies the fault identification problem for linear control systems under the unmatched disturbances. A novel approach to the construction of a sliding mode observer is proposed for systems that do not satisfy common conditions required for fault estimation, in particular matching condition, minimum phase condition, and detectability condition. The suggested approach is based on the reduced order model of the original system. This allows to reduce complexity of sliding mode observer and relax the limitations imposed on the original system.

10

Literature survey of interleaved DC-DC step-down converters for proton exchange membrane electrolyzer applications

Guida Vittorio, Guilbert Damien, Douine Bruno

Transactions on Environment and Electrical Engineering

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2019

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Vol. 3, No. 1

33--43

EN

Recently, the use of electrolyzers for hydrogen production through water electrolysis is of great interest in the industrial field to replace current hydrogen production pathways based on fossil fuels (e.g. oil, coal). The electrolyzers must be supplied with a very low DC voltage in order to produce hydrogen from the deionized water. For this reason, DC-DC step-down converters are generally used. However, these topologies present several drawbacks from output current ripple and voltage gain point of view. In order to meet these expectations, interleaved DC-DC step-down converters are considered as promising and interesting candidates to supply proton exchange membrane (PEM) electrolyzers. Indeed, these converters offer some advantages including output current ripple reduction and reliability in case of power switch failures. In addition, over the last decade, many improvements have been brought to these topologies with the aim to enhance their conversion gain. Hence, the main goal of this paper is to carry out a thorough state-of-the-art of different interleaved step-down DC-DC topologies featuring a high voltage gain, needed for PEM electrolyzer applications.

11

Szyby zespolone w systemach fasadowych

Ambroziak A.

Materiały Budowlane

|

2018

|

nr 9

50--51

PL

W artykule przedstawiono wybrane kryteria techniczne stosowane do oceny jakościowej izolacyjnych szyb zespolonych. Bazując na własnych doświadczeniach, autor zwrócił uwagę na pojawiające się problemy w trakcie odbiorów technicznych na budowie. Przedstawiono także krótki przegląd literatury z zakresu szkła budowlanego i szyb zespolonych.

EN

The article addresses selected technical requirements for quality assessment of insulating window panels. Based on the author's experience the problems are pointed out of site supervisory on building site. A short literature review of both glass and window panels is presented too.

12

Miocene transpression effects at the boundary of Central Carpathian Paleogene Basin and Pieniny Klippen Belt - examples from Polish-Slovakian borderland

Ludwiniak M.

Geology, Geophysics and Environment

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2018

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Vol. 44, no. 1

91--100

EN

A geological structural study has been conducted along the tectonic contact zone of the Central Carpathian Paleogene Basin (CCPB) and Pieniny Klippen Belt (PKB) in the eastern Podhale and western Spišska Magura areas. It concerned mostly the Central Carpathian Paleogene flysch strata and, to a lesser degree, the Upper Cretaceous rocks of the PKB. Tectonic deformation structures genetically related to the important tectonic boundary in question occur within a c. 1.5–2 km-wide strip of the Paleogene flysch rocks adjacent from the south to the PKB. Two parallel structural domains have been distinguished within this strip: the contact zone proper in the north and the peri-Pieniny monocline in the south. Most of the minor faults documented in the Paleogene flysch bear a record of dextral motion parallel to the contact zone. Some dextral-reverse oblique slip faults of NE-SW and W-E trends have also been recognized. Discrepancies in the orientation and sense of movement on strike-slip faults in the Paleogene flysch rocks and those in marlstones of the “klippen envelope” of the PKB were encountered. They probably reflect differences in the structural history of both the adjacent rock complexes, as the Upper Cretaceous deposits of the PKB must have experienced more deformation events and, in general, were affected by much more intense strain than those of the CCPB. Contractional structures, such as south-vergent reverse faults and recumbent folds which point to ca N-S tectonic shortening, have also been found in the Paleogene rocks. The entirety of the structural features found in the CCPB is characteristic of a transpressional regime. The regionally consistent coexistence of structures resulting from strike-slip movements and tectonic shortening, as well as features pointing directly to a transpressional regime, prove the transpressional dextral nature of the contact between the CCPB and PKB.

13

Fault diagnosis of sensors, actuators and wind turbine system

Azzouzi M., Diarra R., Popescu D.

Diagnostyka

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2018

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Vol. 19, No. 4

3--10

EN

The production capacity of installed wind power greatly increases in worldwide. Hence the interest is focused on the reliability and efficiency of wind turbines; then to reduce the production cost and increase the yield. The main objective of our research in this work is to diagnose wind system. We presented a state of the art of diagnosis approach applied on wind turbines and various occurred faults which should be detected and isolated in the wind turbine parts. After that, an overview on this proposed solution for wind turbines, which opted for a diagnostic strategy based on support vector machines (SVM). A Benchmark of a wind power of 4.5 MW with faults on sensors, actuators and the systems was presented. Defects of the Benchmark are in the pitch system, the drive system, the generator and the converter. We tested then the effectiveness of the used method by visualizing simulation results of diagnosis in two different scenarios.

14

Ocena zachowania się uskoku w sąsiedztwie eksploatacji w aspekcie zagrożenia sejsmicznego

Burtan Z., Chlebowski D., Cieślik J., Zorychta A.

Zeszyty Naukowe Instytutu Gospodarki Surowcami Mineralnymi i Energią PAN

|

2017

|

nr 99

185--197

PL

W artykule, na podstawie programu obliczeniowego bazującego na metodzie elementów skończonych, przeprowadzono numeryczne modelowanie eksploatacji w sąsiedztwie uskoku. Przyjęto, że uskok stanowi pojedyncza nieciągłość w postaci płaszczyzny zorientowanej pionowo, a warunki na stykających się powierzchniach definiuje prawo tarcia Coulomba. Rezultaty obliczeń dotyczyły reakcji uskoku na dodatkowe obciążenie wywołane eksploatacją górniczą, a także odnosiły się do wpływu zjawisk zachodzących w płaszczyźnie uskoku na bezpośrednie otoczenie pola eksploatacji. Zachowanie się uskoku analizowano w funkcji rozwoju eksploatacji opierając się na rozkładach naprężeń stycznych i poślizgu wraz z ich zasięgiem w płaszczyźnie uskoku oraz energii zdyssypowanej wskutek tarcia. Z kolei wpływ uskoku na jego otoczenie oceniano na podstawie zmian gęstości całkowitej energii odkształcenia sprężystego. Rezultaty przeprowadzonego modelowania numerycznego pozwoliły na sformułowanie wniosków dotyczących prowadzenia eksploatacji w sąsiedztwie dyslokacji tektonicznych w aspekcie kształtowania się poziomu zagrożenia sejsmicznego.

EN

This article concerns numerical modeling of the impact of mining operations on fault behavior, carried out on the basis of a calculation program based on the finite element method. It was assumed that the fault is a single discontinuity in the form of a vertically-oriented plane, and the conditions in which surfaces merge are defined by the right of the Coulomb friction. On the one hand, the calculations are related to the fault’s response to additional weight resulting from mining operations, and on the other, they are related to the impact that occurrences in the fault’s plane had on the immediate surroundings of the extraction center. The behavior of the fault was analyzed based on distributions in the plane of shear stress and slip, together with their range and energy dissipated due to friction. In turn, the impact of the fault on its immediate environment was analyzed based on variations in the total energy density of elasticity. The results of numerical modeling made it possible to draw conclusions concerning mining operation in the proximity of tectonic dislocations in the context of seismic hazard’s levels.

15

Stepwise clockwise rotation of the Cenozoic stress field in the Western Carpathians as revealed by kinematic analysis of minor faults in the Manín Unit (western Slovakia)

Šimonová V., Plašienka D.

Geological Quarterly

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2017

|

Vol. 61, No. 1

251--264

EN

This study aims at quantitative kinematic analysis of fault-slip data and palaeostress reconstruction of polyphase brittle structures developed in the Manín Unit cropping out in the Middle Váh River Valley of western Slovakia. The Manín Unit neighbours the Pieniny Klippen Belt that follows the boundary between the Paleogene accretionary wedge of the Outer Carpathians and the Cretaceous nappe system of the Central Western Carpathians. After the nappe emplacement during mid-Cretaceous times, the Manín Unit was incorporated into the Pieniny Klippen Belt and attained its complex tectonic style. Based on kinematic analysis of meso-scale faults with slickensides, six (D1–D6) brittle deformation stages have been discerned. The relative succession of individual palaeostress states was derived from field structural relationships; their stratigraphic age was estimated primarily by comparison with other published data. Palaeostress analysis in the Manín Unit revealed the existence of six different palaeostress fields acting from the Middle Eocene to the Quaternary. The first three generations of meso-scale brittle structures were formed under a transpressional tectonic regime during the pre-Late Eocene–Early Miocene D1–D3 deformation. Generally, the maximum horizontal stress axis rotated clockwise from a W–E to an approximately N–S direction. Thereafter, a transtensional tectonic regime was characterized by a WNW–ESE to NNW–SSE oriented minimum horizontal stress axis during Middle and Late Miocene D4–D5 deformation. A general extensional tectonic regime influenced the structural evolution of the area in the Pliocene to Quaternary, when a gradual reorientation of the palaeostress field resulted in the development of variable, often reactivated, fault structures.

16

Określanie właściwości uszczelniających uskoków na podstawie modelowania z wykorzystaniem danych sejsmicznych i geofizyki otworowej – rozwiązania programowe opracowane w firmie Geofizyka Toruń S.A.

Rudzki M.

Prace Naukowe Instytutu Nafty i Gazu

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2016

|

nr 209 wyd. konferencyjne

197--200

PL

Referat przedstawia zarys metodyki numerycznego wyznaczania parametrów charakteryzujących własności uszczelniające powierzchni uskokowych, w oparciu o dane sejsmiczne i geofizyki wiertniczej. Przedstawiono ogólny schemat postępowania oraz wyniki zastosowania procedur numerycznych, opracowanych w firmie Geofizyka Toruń S.A.

EN

The paper presents an outline of the method of calculating the parameters characterising the seal properties of faults, basing on seismic and well-logging data. The general workflow, together with the results of numerical procedures developed in Geofizyka Toruń S.A. are presented.

17

Characteristics and origin of deformation structures within lignite seams : a case study from Polish opencast mines

Widera M.

Geological Quarterly

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2016

|

Vol. 60, No. 1

181--191

EN

The present paper discusses the genesis of some deformation structures within Miocene lignite seams in Poland. These meso- to macro-scale deformation structures are the best developed in areas where the thickest lignite seams are exploited, that is, in the Bełchatów, Turów and Lubstów lignite opencast mines. They show a wide variety of structures such as high-angle inclined strata, normal and reverse faults and folds, fractures and clastic dikes. These deformation structures were not analysed in terms of the structural development of the lignite-bearing areas, but rather in the context of their origin. The high-angle inclination of clastic sedimentary strata clearly formed mainly as a result of vertical tectonic movements in the sub-Cenozoic basement, their currently measured dip angle being significantly higher than their natural angle of repose. All the observed normal and reverse faults cutting the Miocene strata are a clear example of syn- and/or post-depositional tectonics. The normal faults clearly indicate tensional tectonics while the reverse faults reflect compressional tectonics. In turn, the majority of folds occurring within the lignite seams are a result of peat/lignite compaction. However, one of the folds studied is predominantly the result of vertical displacements in the sub-Cenozoic basement. The en echelon fracture pattern may additionally indicate the horizontal component of these displacements. Finally, the most spectacular and debatable structures are clastic dikes. In this study the genesis of some of them is linked with the evolution of the graben’s marginal fault.

18

Structurally altered hard coal in the areas of tectonic disturbances – an initial attempt at classification

Godyń K.

Archives of Mining Sciences

|

2016

|

Vol. 61, no. 3

677--694

EN

As regards the exploitation of hard coal seams, the near-fault zones and faults themselves are considered to be particularly dangerous areas, which is due to a high probability of the occurrence of gasogeodynamic phenomena. Tectonic dislocations running across a seam have a destructive impact on coal. Degradation of the coal structure, particularly visible in the microscale, is reflected in the coal’s strength or gas properties. Such “structurally altered” coal is characterized by the presence of numerous fracturings, crushed areas, or dislocations of some of its fragments, and sometimes even the total destruction of the original structure. The present paper provides a detailed analysis and description of near-fault coal obtained from selected seams of the Upper Silesian Coal Basin, completed due to the application of optical methods. Both the type and the degree of changes in the structure of such coal were identified. On this basis, the author attempted to systematize the nomenclature used in relation to selected Upper Silesian hard coal seams, which, in turn, resulted in a proposed classification of the “altered structures” of the near-fault coal.

PL

Podczas eksploatacji węgla kamiennego, za szczególnie niebezpieczne obszary, ze względu na możliwość wystąpienia zjawisk gazo-geodynamicznych, uważa się strefy przyuskokowe i same uskoki. Przebiegające przez pokład dyslokacje tektoniczne wpływają destrukcyjnie na węgiel. Degradacja struktury węgla dostrzegalna, szczególnie w skali mikro, ma odzwierciedlenie w jego cechach wytrzymałościowych czy też gazowych. Taki, „odmieniony strukturalnie” węgiel, charakteryzuje się występowaniem licznych spękań, skruszeń, czy przemieszczeń poszczególnych fragmentów, a niekiedy i całkowitym zniszczeniem pierwotnej struktury. W pracy, posługując się metodami optycznymi, dokonano szczegółowych obserwacji i opisu węgla przyuskokowego pobranego z wybranych pokładów Górnośląskiego Zagłębia Węglowego. Zidentyfikowano rodzaj i intensywność zmian w strukturze takiego węgla. Na tej podstawie podjęto próbę usystematyzowania stosowanego nazewnictwa w odniesieniu do wybranych górnośląskich pokładów węgla kamiennego, co w konsekwencji zaowocowało zaproponowaniem klasyfikacji „struktur odmienionych” tego przyuskokowego węgla.

19

Numerical modeling of exploitation relics and faults influence on rock mass deformations

Wesołowski M.

Archives of Mining Sciences

|

2016

|

Vol. 61, no. 4

893--906

EN

This article presents numerical modeling results of fault planes and exploitation relics influenced by the size and distribution of rock mass and surface area deformations. Numerical calculations were performed using the finite difference program FLAC. To assess the changes taking place in a rock mass, an anisotropic elasto-plastic ubiquitous joint model was used, into which the Coulomb-Mohr strength (plasticity) condition was implemented. The article takes as an example the actual exploitation of the longwall 225 area in the seam 502wg of the “Pokój” coal mine. Computer simulations have shown that it is possible to determine the influence of fault planes and exploitation relics on the size and distribution of rock mass and its surface deformation. The main factor causing additional deformations of the area surface are the abandoned workings in the seam 502wd. These abandoned workings are the activation factor that caused additional subsidences and also, due to the significant dip, they are a layer on which the rock mass slides down in the direction of the extracted space. These factors are not taken into account by the geometrical and integral theories.

PL

Obecnie większość prognoz deformacji powierzchni terenu wywołanych eksploatacją górniczą wykonuje się na podstawie metod geometryczno-całkowych. Metody te charakteryzują się nie tylko znaczną prostotą, ale także pozwalają na uzyskanie stosunkowo dobrych opisów rzeczywistych deformacji nawet w przypadku bardzo skomplikowanych kształtów pól eksploatacyjnych. Jednak w przypadku, gdy górotwór jest znacznie zaburzony tektonicznie lub naruszony wcześniejszą eksploatacją górniczą, zastosowanie metod geometryczno-całkowych nie daje już tak zadowalających rezultatów. Dlatego też w ostatnim czasie rozwinął się nowy kierunek badań, który do opisu zjawisk deformacyjnych zachodzących w górotworze z powodzeniem wykorzystuje techniki obliczeniowe, opierające się głównie na rozwiązaniach z dziedziny mechaniki ośrodków ciągłych. Wśród znanych metod obliczeniowych wymienić należy metody: elementów skończonych, różnic skończonych, elementów brzegowych oraz elementów odrębnych. Metody te znajdują powszechne zastosowanie w zagadnieniach związanych z mechaniką skał, a także problematyką ochrony terenów górniczych. Przebieg procesu deformacji jest ściśle związany z warunkami geologicznymi rozpatrywanego górotworu. Jako najważniejsze z tych warunków wymienić należy między innymi istniejące deformacje tektoniczne znajdujące się w zasięgu oddziaływania eksploatacji górniczej oraz zaszłości eksploatacyjne w postaci słabo udokumentowanych zrobów (Kowalski et al., 2010). Obecność w górotworze uskoków oraz dużych płaszczyzn pęknięć może powodować znaczne zaburzenia procesów deformacyjnych (Majcherczyk et al., 2011, Ścigała, 2013). Występowanie tego typu zaburzeń może być powodem tworzenia się na powierzchni deformacji nieciągłych w postaci progów eksploatacyjnych lub szczelin w warstwie nadkładowej. W przypadku występowania zaszłości eksploatacyjnym może dojść do zjawisk ich reaktywacji, które w znacznym stopniu mogą zwiększać zasięg powstałych deformacji powierzchni terenu. Należy w tym miejscu podkreślić, że prawidłowy opis tego typu czynników przy wykorzystaniu metod geometryczno-całkowych najczęściej stosowanych do prognozowania deformacji powierzchni terenu jest praktycznie niemożliwy W artykule przedstawiono wyniki modelowania numerycznego wpływu płaszczyzn uskokowych oraz zaszłości eksploatacyjnych na wielkość i rozkład deformacji górotworu oraz powierzchni terenu. Obliczenia numeryczne przeprowadzono z wykorzystaniem programu różnic skończonych FLAC. Do oceny zmian zachodzących w górotworze wykorzystano anizotropowy sprężysto-plastyczny model ubiquitous joint, w którym zaimplementowano warunek wytrzymałościowy (uplastycznienia) Coulomba-Mohra. Model ten jest anizotropowym ośrodkiem plastycznym zawierającym płaszczyzny osłabienia określonej orientacji. W artykule posłużono się przykładem rzeczywistej eksploatacji rejonu ściany 225 w pokładzie 502wg w KWK „Pokój”. Na podstawie wykonanych symulacji komputerowych można stwierdzić, że głównym czynnikiem powodującym dodatkowe deformacje powierzchni terenu są stare zroby w pokładzie 502wd. Zroby te pełnią funkcję aktywacyjną powodując dodatkowe obniżenia, a ponadto wskutek znacznego upadu stanowią warstwę, po której ześlizguje się górotwór w kierunku wybranej przestrzeni, powodując znaczne zwiększenie obniżeń terenu po stronie wzniosu warstw górotworu. Proponowany w artykule schemat modelowania może być wykorzystany do uzupełnienia procesu prognostycznego o elementy dotychczas nieuwzględniane we wcześniejszych pracach.

20

Enhancement of Seismic Data Processing and Interpretation of Fracture Zones on the Upper Part of Granitic Basement in Cuu Long Basin, Vietnam

Tan M. T., Ha M. T., Marfurt K. J., Hieu N. T., Hanh N. T. M.

Acta Geophysica

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2016

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Vol. 64, no. 6

2214--2231

EN

The fractured granite basement is the primary oil and gas reservoir in the Cuu Long Basin, Vietnam. Due to the complexity of this nonlayered unconventional target, combined with complicated fault and fracture systems, the seismic data quality near and within the basement section is very low. For this reason, it is important to apply improved seismic data processing workflows, filtering and migration techniques, as wells as attribute processing methods to enhance the imaging quality. Our studies show that applying different types of filters, including the f-k, Radon transform and Tau-P, improves signal to noise ratio, removing multiples, revealing basement’s top and its related fractured and fault zones. In addition, the application of multi-arrival-solution migration algorithms, such as Kirchhoff Migration and Controlled Beam Migration, provides improved imaging for identifying basement top and faults and fractures within the basement. Furthermore, the application of seismic attributes such as curvature, apparent dip, or energy gradient, is important in locating faults and fractures, whereas mapping of intensity and orientation of such structures assists the delineation of “sweet spots” and assists the planning of exploration.