Wyniki wyszukiwania - BazTech

1

Kotwy iniekcyjne w gruntach i skałach

Roguska Emilia

Materiały Budowlane

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2024

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nr 2

61--65

2

Reductıon of thermal tensıons and temperatures formed ın the trıbonodes and surfaces of the equıpment and tools used ın well workover and restoratıon works

Mustafayev Amir G., Nasirov Chingiz R.

Nafta-Gaz

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2023

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R. 79, nr 10

661--669

EN

The maintenance of equipment and tools used in the workover of oil and gas wells depends on keeping them in good working condition, maintaining the reliability, strength, and temperature endurance of the tool. To restore wells after an accident and bring them back into operation, it is necessary to speed up the drilling and repair work by choosing the right repair equipment and following the existing rules and regulatory documents. The cutting elements of tools working under high pressure and loads are deformed, a tense situation is created in the cutting – a destruction zone and high temperatures (1000–1200°C) occur because of corrosion in the triboknots. The stress-deformation state in the cutting-destruction zone causes the formation of microcracks in the working area of the tool. Microcracks grow after a certain period. Cutting elements are quickly worn, in some cases break and fail quickly. Such cases affect the structural composition of the cutting elements, an increase in temperatures; as a result, riveting occurs. In order to keep the equipment and tools used in the repair in normal working condition, adjusting the mode parameters is one of the important requirements, in addition to taking special care of them. Optimum results obtained in repair and restoration depend on the efficiency of the cutting-destructive tool, longevity, material selection, construction manufacturing technologies, tools that meet modern requirements, dimensions, weight, and internal condition of the well being restored. It is necessary to keep the heat generated in the moving parts of the tool at the required level for the safe performance of restoration work. The thermal regime of cutting and rock-destroying tools depends on the physical-mechanical properties of the objects subjected to destruction, and the effect of thermomechanical stresses generated on the contact surfaces of the tool and the amount of heat released from the working surface. Studying the problems related to heat issues will ensure the temperature tolerance of not only the repair equipment, but also the equipment and tools used in other areas of the oil-field industry.

PL

Utrzymanie urządzeń i narzędzi używanych w rekonstrukcjach odwiertów ropy i gazu zależy od zachowania ich w stanie gotowości do pracy, niezawodności, wytrzymałości oraz trwałości temperaturowej narzędzia. Aby przywrócić odpowiedni stan odwiertów po awarii oraz ponownie rozpocząć ich eksploatację trzeba przyspieszyć prace wiertnicze i naprawy poprzez wybranie właściwych urządzeń naprawczych oraz przestrzeganie istniejących przepisów i dokumentów regulacyjnych. Elementy tnące narzędzi pracujących pod wysokim ciśnieniem i obciążeniami ulegają deformacji, wytwarza się sytuacja naprężenia w strefie tnąco-niszczącej i występują wysokie temperatury (1000–1200°C) w wyniku korozji w węzłach tarcia. Stan naprężenie-odkształcenie w strefie tnąco- -niszczącej powoduje tworzenie mikropęknięć w obszarze roboczym narzędzia. Mikropęknięcia propagują po pewnym czasie. Elementy tnące szybko się zużywają, w niektórych przypadkach szybko pękają i ulegają awarii. Takie przypadki wpływają na skład strukturalny elementów tnących, wzrost temperatury i w rezultacie następuje unieruchomienie. Aby utrzymywać urządzenia i narzędzia używane przy naprawie w normalnych warunkach roboczych, jednym z najważniejszych wymogów jest dostosowanie parametrów trybu pracy, oprócz objęcia ich specjalną uwagą. Dobre wyniki uzyskane w robotach naprawczych i renowacyjnych zależą od sprawności narzędzia tnąco-niszczącego, trwałości, doboru materiałów, technologii produkcji konstrukcji, narzędzia spełniającego nowoczesne wymagania, jego wymiarów, wagi oraz stanu wewnętrznego odwiertu podlegającego renowacji. Dla bezpiecznego wykonania prac renowacyjnych konieczne jest utrzymanie ciepła generowanego w częściach ruchomych narzędzia na wymaganym poziomie. Reżim cieplny narzędzi tnących i niszczących skałę zależy od właściwości fizyko-mechanicznych obiektów podlegających niszczeniu i efektu naprężeń termomechanicznych generowanych na powierzchniach kontaktowych narzędzia oraz od ilości ciepła uwolnionej z powierzchni roboczej. Badanie problemów związanych z zagadnieniami ciepła pozwoli na zapewnienie tolerancji temperaturowej nie tylko urządzenia naprawczego, ale również urządzeń i narzędzi używanych w innych dziedzinach przemysłu złóż ropy.

3

Method for calculation of the carrying capacity of the bottomhole zone of a gas-bearing formation

Rizo Zakhar, Vasyliev Leonid, Vasyliev Dmytro, Avramenko Stanislav

Mining Science

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2023

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Vol. 30

135--145

EN

This paper presents a method for calculating vertical and horizontal stresses in gas-bearing coal seams based on a set of equations developed by the authors. The method describes the experimental curve of rock pressure as a convex quadratic function, with the initial value of the function equal to the normal stress at the top of the bottom hole crack. The method also considers the variation of gas pressure as the crack moves towards the interior of the formation. In addition, the method employs the relationship between active tangential stresses at points on the edges of the bottomhole crack, derived from Coulomb’s strength criteria for brittle materials. The accuracy of the method was confirmed by experimental data on the maximum shear strength of marble and brown coal at various levels of confining pressure and pore pressure. The paper also presents analytical expressions for the strength limit of the bottomhole zone of gas-bearing coal seams as a function of gas pressure gradient.

4

Study of rational regime and technological parameters of the hydromechanical drilling method

Ihnatov Andrii, Haddad Jamil Sami, Koroviaka Yevhenii, Aziukovskyi Oleksandr, Rastsvietaiev Valerii, Dmytruk Olena

Archives of Mining Sciences

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2023

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Vol. 68, no. 2

285--299

EN

The function of breaking deformations within the rock mass in the bottomhole of a hydromechanical drilling well is dependent on various technological means and methods. A sequential analysis has been conducted to identify the most influential factors in this process. Positive features of hydromechanical drilling have been outlined from the viewpoint of effective intensification of basic technical and economic parameters of the process of well construction with different purposes. Complete operational similarity and technological interconnection of a mechanism of the formation of different parts of a hydromechanical drilling well have been shown in terms of their stipulation by the properties of rock formations and mode support of a well construction process. Top-priority of a hydromechanical drilling type has been proved to generate as many parameters of dynamic effect on rock mass, which results in the increasing scope of bottomhole breaking processes. Attention has been paid to the study of the problem of tool support for drilling operations from the viewpoint of tracing the nature of bottomhole processes running in terms of different technical and technological factors. The possibility and necessity of using surface-active substances (SAS) as the main activators of positive deformation interactions in the “metal pellets – rock” pair have been proved and substantiated; use will be based on the developed methodological approaches of rational selection of a component-concentration composition of a breaking medium. Originality. The efficiency of a hydromechanical drilling type is stipulated by the degree of dynamic effect on the rock bottomhole; depending on its geological-mineralogical and physicomechanical features, it can be intensified by increasing frequency of impacting, interpretation of the effecting mechanism, variation of the cleaning agent type as well as directed activation of the manifestation of surface and interphase interactions. Practical implications. The represented results of analytical and laboratory-experimental studies are the basis for the development of methodological foundations to elaborate the mode parameters of the technology of hydromechanical drilling for the construction of wells. They belong to the basic initial data applied while developing the design and working characteristics of the corresponding modernised operating members.

5

On the resistance of concrete hollow thin-walled high piers to rock collisions

Huang Yao

Archives of Civil Engineering

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2023

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Vol. 69, nr 3

187--197

EN

Concrete hollow thin-walled high piers (CHTWHPs) located in mountainous areas may be destroyed by the huge impact force of accidental rocks. The study focuses on analyzing the effects of rock impact on the pier, including its impact force, pier damage, dynamic response, and energy dissipation characteristics. The results show that: (1) Increasing the impact height led to a decrease in the peak impact force. Specifically, 15.5% decrease in the peak collision force is induced when the height of rock collision rises from 10 m to 40 m. (2) The damage mode of the pier’s collision surface is mainly oval damage with symmetrical center, radial damage on the side surface, and corner shear failure on the cross section. (3) The peak displacement of bridge pier increases with the increase of collision height. As the collision height increased from 10 m to 40 m, the bridge pier’s peak displacement also increased, rising by 104.2%. (4) The concrete internal energy gradually decreased with increasing collision height, dropping by 36.9% when the height of rock collision rises from 10 m to 40 m. The reinforcement internal energy showed an increase of 78%. The results of this study may provide reference for the rock collision resistance design of CHTWHPs.

6

Influence of Anchor Depth and Friction Coefficient Between Anchor and Rock on the Trajectory of Rock Masses Detachment

Jonak Józef, Karpiński Robert, Wójcik Andrzej

Advances in Science and Technology. Research Journal

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2023

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Vol. 17, no 4

290--298

EN

This work presents the results of a FEA (Finite Element Analysis) concerning the propagation of the fracture tra- jectory during the detachment of rock masses. The analysis considers mechanical anchoring parameters, including the depth of anchoring and the friction between the anchor head and the brittle material. The analysis involved varying the effective anchorage depth hef = 50, 100, and 150 mm, along with considering different coefficients of friction (μ) for the anchor head against the rock, including 0.15, 0.3, and 0.45. The results indicated that within the chosen range of anchorage depths, the extent of damage increases with the depth of anchor embedment. However, the depth of anchoring, considering the studied range of this parameter and the assumed mechanical properties of the rock, did not have a significant effect on the value of the angle cone (α0) during the initial phase of the medium’s destruction. For the friction coefficient μ = 0.15, there is a clear deep penetration into the fracture at its initial stage of development (at the initial angle of α0 = -20°), promoting further spread of the fracture on the free surface. For larger values of the friction coefficient (μ = 0.3 and 0.45) – the trend is less pronounced (α0 = -2°÷-8°) resulting in a decrease in the crack range.

7

An evaluation method of rock pore volume compressibility determination using a computed tomography scanned based finite element model

Moosavi Seyed Amin, Goshtasbi Kamran, Kazemzadeh Ezzatollah

Acta Geophysica

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2023

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Vol. 71, no. 1

147--159

EN

This paper has proposed a new perspective of studying internal structure-based tests, the results of which will improve the present experimental methods and enrich our understanding of rock structure-based modeling without any core preparations, with low cost in a short time. Pore volume compressibility (PVC) is an important feature of rock and is related to mechanical and structural behavior of porous rock sample. An accurate evaluation of pore volume compressibility depends on experimental test which is time-consuming and costly. This paper outlines new method for evaluation of PVC of rock cores using a computed tomography (CT) scan-based finite element method (FEM). The verification studies were performed on a series of porous rock cores which were extracted from deep oil reservoirs in Iran. In order to construct a finite element model, a relationship between spatial elastic properties of samples and CT-scanned data images was derived. The samples were scanned by a conic beam computed tomography (CBCT) machine, and the scanned data were converted into a model to simulate PVC tests. The pore volumetric strains were obtained from a linear elastic analysis for each stress and pore pressure step. To validate the finite element analysis (FEA) results, a series of experimental PVC tests were conducted on the pre-scanned samples and PVC curves were extracted. As a result, the predictions calculated from the CT scan-based numerical models have shown a good correlation with the results obtained from laboratory experiments. The results revealed that it is possible to simulate PVC tests using this numerical proposed evaluation method in such a way that the cost and time of the tests were lowered.

8

Interakcja wodoru ze skałą zbiornikową

Cicha-Szot Renata, Leśniak Grzegorz

Nafta-Gaz

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2022

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R. 78, nr 8

580--588

PL

Istnieje szereg metod magazynowania wodoru, do których zaliczyć można stosowanie zbiorników napowierzchniowych, wiązanie w wodorkach metali, nanorurkach węglowych, sieciach metaloorganicznych, ciekłych organicznych nośnikach wodoru czy adsorbentach. Jednak to podziemne magazynowanie wodoru w strukturach geologicznych (PMW) wydaje się kluczowe dla rozwiązania problemu długoterminowego magazynowania dużych ilości energii oraz zwiększenia stabilności sieci energetycznej i poprawy wydajności systemów energetycznych. Kryteria wyboru struktury do magazynowania wodoru obejmują szereg czynników technicznych, ekonomicznych, ekologicznych i społecznych. Jednym z najmniej rozpoznanych obszarów badawczych dotyczących PMW jest utrata wodoru in situ wywołana reakcjami geochemicznymi, które mogą wpływać na parametry petrofizyczne oraz wytrzymałość skał uszczelniających. W artykule przeanalizowano reakcje, jakie mogą wystąpić podczas magazynowania wodoru w strukturach geologicznych. Na podstawie studium literaturowego wskazano grupy minerałów, które mogą wpływać na zmiany pojemności magazynowej oraz na czystość gazu. Należą do nich w szczególności węglany, anhydryt, ankeryt i piryt, które stanowiąc skład matrycy skalnej lub cementu, mogą znacząco wpływać na potencjał magazynowy analizowanej struktury. Podczas kontaktu z wodorem minerały te ulegają rozpuszczeniu, w wyniku czego uwalniane są m.in. jony Fe2+, Mg2+, Ca2+, SO4 2−, HCO3 − , CO3 2−, HS− . Jony te wchodzą nie tylko w skład minerałów wtórnych, ale również na skutek dalszych reakcji z wodorem zanieczyszczają magazynowany nośnik energii domieszkami CH4, H2S i CO2, co ogranicza możliwości dalszego wykorzystania wodoru. Zwrócono również uwagę na możliwość wystąpienia rozpuszczania kwarcu, którego szybkość zależy od stężenia jonów Na+ w solance złożowej oraz pH. Ponadto pH wpływa na reaktywność wodoru i zależy w dużej mierze od temperatury i ciśnienia, które w trakcie pracy magazynu będzie podlegało częstym cyklicznym zmianom. W artykule omówiono wpływ warunków termobarycznych na analizowany proces, co powinno stanowić podstawę do szczegółowej analizy oddziaływania skała–wodór– solanka dla potencjalnej podziemnej struktury magazynowej.

EN

There are several hydrogen storage methods, including surface tanks, metal hydrides, carbon nanotubes, organometallic networks, liquid organic hydrogen carriers, or adsorbents. However, underground hydrogen storage (UHS) appears to be crucial in solving the problem of long-term storage of large amounts of energy, increasing the power grid's stability and improving energy systems' efficiency. The criteria for selecting a hydrogen storage structure include a number of technical, economic, ecological, and social factors. One of the least recognized research areas concerning UHS is the in situ loss of hydrogen caused by geochemical reactions that may affect sealing rocks' petrophysical parameters and strength. The article presents the reactions that may occur during hydrogen storage in geological structures. Based on a literature study, groups of minerals that may affect changes in storage capacity and gas purity have been indicated. These include, in particular, carbonates, anhydrite, ankerite, and pyrite in both the rock matrix and the cement. Upon contact with hydrogen, these minerals dissolve, releasing, among others, Fe2+, Mg2+, Ca2+, SO4 2– , HCO3 – , CO3 2– , HS– ions. These ions are not only components of secondary minerals but also, as a result of further reactions with hydrogen, pollute the stored energy carrier with admixtures of CH4, H2S and CO2, which limits the possibilities of further hydrogen use. The possibility of quartz dissolution, the rate of which depends on the concentration of Na+ ions in the reservoir brine and the pH, was also noted. Moreover, pH influences the reactivity of hydrogen and depends mainly on temperature and pressure, which will be subject to frequent cyclical changes during the operation of the storage. This review paper discusses the influence of thermobaric conditions on the analyzed process, what should be a base for detailed analysis of the rock-hydrogen-brine interaction for the potential underground storage structure.

9

Investigation on rock cutting characteristics of spherical-tooth hob

Zhang Xuhui, Long Zhaomin, Liao Yashi, Long Jinjing, Liu Jifu

Mining Science

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2022

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Vol. 29

121--144

EN

To study the rock cutting characteristics of spherical-tooth hob, the rock cutting process induced by the spherical-tooth hob is analyzed based on the finite element simulation and the rock cutting experiments. Then the rock breaking states, rock cutting forces and rock cutting efficiency caused by the spherical-tooth hob under different penetrations are obtained. The results show that a cutting groove and a series of pits in the cutting groove will be produced when the penetration exceeds 9 mm. At such penetration, the spherical teeth and the cutter ring can cooperate to cut rock. The cutting forces curves show obvious fluctuation and the peak values of cutting forces correspond to the moment when a spherical tooth intrudes into the rock sample totally. The cutting forces increase with the growth of the penetration and the increase speed turns fast when the penetration exceeds 9 mm. With the increase of penetration, the specific energy consumption of the spherical tooth hob first decreases and then increases. It exists an optimal penetration of 12 mm to achieve the highest rock cutting efficiency.

10

Study of rock fracture under blast loading

Baranowski Paweł, Kucewicz Michał, Pytlik Mateusz, Małachowski Jerzy

Bulletin of the Polish Academy of Sciences. Technical Sciences

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2022

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Vol. 70, nr 5

art. no. e141723

EN

A study of dolomite rock material failure using a simple small-scale blast setup is presented. Laboratory tests were conducted using disc specimens drilled with a borehole in the center. A detonation cord and a blasting cap were fitted inside the borehole to induce cracking and fracturing of the specimens. The specimens were inserted between two steel plates, which were compressed against the specimen using bolt screws. Prior to testing, the most suitable screw torque for constraining the vertical displacement of the specimen surfaces without compressing the specimen was selected based on numerical simulations. Then, the experimental tests with the blasting cap were simulated using the Johnson–Holmquist II (JH-2) material model, and the properties of the blasting cap were determined and verified in two special tests with a lead specimen. Possessing the validated model, the influence of specimen thickness on the cracking patterns was finally analyzed. This paper presents a relatively easy method for studying rock material behavior under blast loading and for validating the numerical and constitutive models used for rock simulations.

11

Significance of a new preliminary treatment method of the Pen206_18 borehole penetrometer’s pressure readouts for a reliable analysis of rock stress-strain parameters

Pierszalik Rafał

Archives of Mining Sciences

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2022

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Vol. 67, no. 1

159--178

EN

This article describes some selected aspects of a preliminary treatment of measurement cycle results obtained by a new Pen206_18 type hydraulic borehole penetrometer (a borehole jack type), a tool of an in situ determining of mechanical properties of rocks. The pre-treatment of the measurement cycle results is a necessary step to prepare the data for a following appropriate analysis of stress-strain parameters of rocks. Aforementioned aspects are focused mainly on a pre-treatment of hydraulic pressure readouts. The Pen206_18 type penetrometer is a modified version of a standard Pen206 type penetrometer. The standard version, based on a digital measurement of a critical hydraulic pressure, has been in use in polish hard coal mines for almost 15 years to determine various rock strength parameters. In contrary, the Pen206_18 type penetrometer now provides simultaneous recording of two main measurement cycle parameters (hydraulic pressure and a head pin stroke) during the whole measurement cycle duration. A recent modification of the penetrometer has given an opportunity to look closer at various factors having an influence on the measurement cycle data readouts and, as a consequence, to lay a foundation for a development a new penetrometric method of determining stress-strain parameters of rocks. In this article it was shown that just before a main stage of the measurement cycle, a transitional stage could occur. It complicates a determination of the beginning of an useful set of measurement cycle data. This problem is widely known also in other static in situ methods of determining stress-strain parameters. Unfortunately, none of various known workouts of this problem were sufficiently adequate to the pre-treatment of the penetrometric measurement cycle results. Hence, a new method of determining the beginning of the useful set of pressure readouts has been developed. The proposed method takes into account an influence of an operational characteristics of the measuring device. This method is an essential part of a new pre-treatment procedure of the Pen206_18 measurement cycle’s pressure readouts.

12

Natural radionuclides in rocks and their association with the mineralogy of rocks in Dakshina Kannada region of southern India

Lokesh Narsha, Vinutha Pudiyaneravana Ramanand, Malleshi Kavasara, Narayana Yerol

Acta Geophysica

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2022

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Vol. 70, no 5

2149--2160

EN

The radioactivity levels of natural radionuclides 226Ra, 232Th, and 40K in the rocks of Dakshina Kannada region of southern India were measured by NaI (Tl) gamma-ray spectrometer. The specific activities of 226Ra, 232Th, and 40K ranged from 4.2±0.4 to 74.5±1.7 Bq kg−1, 14.5±0.7 to 83.5±1.6 Bq kg−1, and 172±3 to 964±7 Bq kg−1 with the mean of 25.1±1.0 Bq kg−1, 36.1±1.0 Bq kg−1, and 502±5.0 Bq kg−1, respectively. The normality of the frequency distribution curves of 226Ra, 232Th, and 40K was tested using the Kolmogorov–Smirnov test. The radiological hazard indices were computed from the measured activity concentration of natural radionuclides in rocks and these were found to be within acceptable levels. To investigate the sources of radioactivity, the minerals involved in the rocks were detected using XRD and FTIR. The mineralogical studies reveal that the principal sources of gamma radiation in the study area are 232Th-rich phosphates and 40K-bearing feldspars.

13

Ocena przepuszczalności skał na podstawie badań sondą aerometryczną

Frolik Adam

Przegląd Górniczy

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2020

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T. 76, nr 6

35--41

PL

Skały karbońskie złożone z piaskowców, mułowców, iłowców i węgli tworzą ośrodek typu warstwowo-szczelinowatego i o ich zdolności do migracji w nim cieczy lub gazów, czyli przepuszczalności lub współczynniku filtracji decyduje obecność w nich szczelin, a nie porowatość ośrodka. Ocena rzeczywistych własności zbiornika warstwowo-szczelinowatego może być zatem dokonana dopiero w badaniach in situ. Jako metodę oznaczenia przepuszczalności oraz współczynnika filtracji skał wykorzystano badania sondą aerometryczną.

EN

Carboniferous rocks composed of sandstone, silt, claystone and coals form a stratified-fracture type medium. So their ability to migrate liquids or gases, such as permeability or filtration coefficient, is determined by the presence of fractures in them, not the porosity of the medium. Therefore, the assessment of the actual properties of the stratified-fractured reservoir can only be made by in situ tests. As a method of determining permeability and rock filtration coefficient, an aerometric probe test was used.

14

Analiza porównawcza metod badania zawartości siarki w rdzeniach wiertniczych, węglu i ropach naftowych

Matyasik Irena, Zapała Marek, Kierat Maria, Wciślak Agnieszka

Nafta-Gaz

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2020

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R. 76, nr 7

449--456

PL

Celem pracy było dobranie i zwalidowanie optymalnej metody analizy zawartości siarki w rdzeniach wiertniczych, w tym pochodzących z pokładów węgla. Ponadto badania zostały przeprowadzone dla rop naftowych. W ramach pracy porównano wyniki badań zawartości siarki metodą analizy elementarnej w dwóch analizatorach: w analizatorze elementarnym EA 1108, który daje możliwość spalania próbek w temperaturze do 1080°C, co nie zawsze jest wystarczające w przypadku próbek geologicznych, oraz w analizatorze Leco CR12 rozbudowanym o moduł do oznaczania siarki, który daje możliwość wykonania analizy w 1350°C. W toku analizy elementarnej następuje przekształcenie siarki wolnej i związanej w dwutlenek siarki SO2, którego zawartość jest mierzona za pomocą różnych detektorów: detektora cieplno-przewodnościowego (TCD) w analizatorze EA 1108 lub detektora podczerwieni w analizatorze Leco CR12. Przed badaniami porównawczymi zwalidowano metodę analizy siarki w analizatorze Leco CR12. Badania porównawcze wykonano dla próbek skalnych, dla węgli i dla rop naftowych oraz dla kerogenu. W ramach pracy przeprowadzono analizy elementarne zawartości siarki dla 23 próbek węgla, 22 próbek skał, 5 próbek kerogenu wydzielonego z tych skał oraz dla 9 rop naftowych. Badane próbki węgla i materiału skalnego pochodziły z rdzeni wiertniczych z otworów poszukiwawczych. Wykazano zgodność stosowanych metod dla kerogenu i dla węgli o zawartości siarki powyżej 0,75% w/w oraz dla rop powyżej 0,3% zawartości siarki. Dużo gorszą zgodność uzyskano dla materiału skalnego z rdzeni wiertniczych, charakteryzującego się dyspersją materii organicznej. Dla próbek o niskiej zawartości siarki bardziej wiarygodnych wyników dostarczają oznaczenia wykonane w analizatorze EA 1108. W przypadku ośrodków o dużej dyspersji substancji organicznej, takich jak warstwy istebniańskie, bardziej wiarygodne są wyniki oznaczeń w analizatorze Leco CR12, ze względu na wielkość próbki analitycznej.

EN

The purpose of the work was to select and validate the optimal method for analyzing sulfur content in drilling cores, including those from coal seams. In addition, research was done for petroleum. As part of the work, the results of sulfur content testing were compared by means of elemental analysis in 2 analyzers: in the EA 1108 elemental analyzer, which gives the possibility of burning samples at temperatures up to 1080°C, which is not always sufficient for geological samples, and in the Leco CR12 analyzer expanded with a module for determination of sulfur, which gives the opportunity to perform the analysis at 1350°C. In the course of elemental analysis, free and bound sulfur is transformed into sulfur dioxide SO2, the content of which is measured by means of various detectors: the thermal conductivity detector (TCD) in the EA 1108 analyzer, or the infrared detector in the Leco CR 12 analyzer. Before the comparative tests, the method of sulfur analysis in the Leco CR 12 analyzer was validated. Comparative studies were carried out for rock samples, for coals, for petroleum and for kerogen. As part of the work, elemental analyses of sulfur content were carried out for 23 coal samples, 22 rock samples, 5 kerogen samples separated from these rocks and for 9 petroleum samples. Tested coal and rock material samples came from drill cores from exploratory wells. The methods used for kerogen and for coals with sulfur content over 0.75 wt % have been shown to be compatible. For oils, compatibility was observed above 0.3% sulfur content. Much worse compliance was obtained for rock matter from drilling cores, characterized by dispersion of organic matter. For samples with low sulfur content, determinations in the EA 1108 analyzer provide more reliable results. For media with a high dispersion of organic matter, such as Istebna Beds, the results of determinations in the Leco CR12 analyzer are more reliable due to the size of the analytical sample.

15

A Pen206 borehole jack suitability assessment for rock mass deformability determination

Pierszalik Rafał, Rajwa Sylwester, Walentek Andrzej, Bier Krzysztof

Archives of Mining Sciences

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2020

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Vol. 65, no. 3

569--590

EN

Currently available field rock mass deformability determination methods are rather difficult to perform, due to their complexity and a time-consuming nature. This article shows results of a suitability assessment of a Pen206 borehole jack (a hydraulic penetrometer) for field rock mass deformability measurements. This type of the borehole jack is widely used in Polish hard coal mining industry. It was originally intended only for quick rock mass strength parameters determination. This article describes an analysis and scope of basic modifications performed mainly on a borehole jack head. It includes discussion of results with possible directions for future development of the device.

16

Geoelektromagnetyczne właściwości skał

Gierlotka Stefan

Napędy i Sterowanie

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2019

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R. 21, nr 1

40--43

PL

Istnienie magnetyzmu znane było ludziom od dawien dawna. Zwrócili uwagę na dziwne kamienie przyciągające żelazo. Były to, jak się później okazało, rudy magnetytu. Przed czterema czy pięcioma tysiącami lat w Chinach przy pomocy magnetytu sporządzono pierwszy kompas. W Europie prymitywnymi kompasami zaczęli posługiwać się Wenecjanie w XII wieku. W niespełna sto lat później żeglarze zwrócili uwagę na fakt, iż namagnesowana igła nie wskazuje dokładnie kierunku północnego bieguna geograficznego. W 1492 roku Krzysztof Kolumb podczas swej podróży przez Ocean Atlantycki stwierdził, że odchylenia te są niejednakowe dla różnych punktów globu ziemskiego. Wielu żeglarzy w miarę posuwania się na północ obserwowało coraz większą różnicę między wskazaniami igły kompasu a kierunkiem bieguna północnego.

17

Influences of the diameter and position of the inner hole on the strength and failure of disc specimens of sandstone determined using the Brazilian split test

Zhu Tantan, Huang Da

Journal of Theoretical and Applied Mechanics

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2019

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Vol. 57 nr 1

127--140

EN

The Brazilian split test on a centrally holed disc (referred to as a ring-disc specimen) is an important indirect method for determining the tensile strength of rock. This paper studies the effect of the diameter d of the center hole and its position, defined by the eccentricity b and the inclination angle of the eccentric hole, on the peak load, failure pattern and horizontal stress of the disc specimen via laboratory experiments and numerical modeling using the finite element method (FEM). Static Brazilian split tests are conducted on an intact disc and three types of holed discs: C-specimens containing a central hole with different diameters, EH-specimens with a horizontally eccentric hole and ER-specimens with a rotationally eccentric hole.

18

Geoelektromagnetyzm skał

Gierlotka S.

Wiadomości Elektrotechniczne

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2018

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R. 86, nr 8

17--20

19

Petrographic study of selected sculptural works of Jan Michałowicz from Urzędów

Ciosmak Małgorzata, Rzęsa Patrycja

Budownictwo i Architektura

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2018

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Vol. 17, nr 3

201--218

EN

Nowadays, in order to determine whether given rock properties make it useful for specifi c purposes, the material is examined using relevant test equipment. At the times of Jan Michałowicz, any knowledge in this respect was transmitted by the master to his apprentices, based on the master’s experience. The artist used domestic rock raw materials to sculpt monuments commemorating important persons who were his contemporaries. For the petrographic analysis, the authors selected the most distinguishable works of the artist, which he signed or which are most likely to have been sculpted by him. The authors analysed the materials used by the artist to carve specifi c elements of his works, as well as rock raw materials in terms of their historical and contemporary properties. Consequently, the petrographic study allowed to describe the rocks in greater detail, as well as their properties useful for sculpture purposes, and their durability. Artistic qualities helped determine the sources of stones used by Jan Michałowicz during his projects. These include the quarries near Pińczów (limestone), Kunów (sandstone), Bolechowice (marble), Żurawno (alabaster) and initially quarries in Hungary. The discussed works of Jan Michałowicz provide firm grounds for acknowledging the artist as the leading co-founder to Polish Renaissance art.

20

Gradual late stage deepening of Gega ice-dammed lake, Tsangpo gorge, southeastern Tibet, indicated by preliminary sedimentary rock magnetic properties

Liu W., Zhou G. G. D., Ge Y., Huang R.

Acta Geophysica

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2018

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Vol. 66, no. 5

907--914

EN

Gega lake, in southeastern Tibet, was formed by the blocking of Yarlung Tsangpo gorge by a glacier and is a well-known example of geomorphological damming. However, the evolution of the damming process at the site is still not understood in detail. Here, we use measurements of multiple magnetic parameters of the sediments from the Yusong (YS) 3 section, which is well-dated by optically stimulated luminescence, to provide a detailed history of the late stage of Gega dammed lake since 17.0 ka. Low-frequency field magnetic susceptibility (χlf) increases upwards gradually from 25 to 79 × 10−8 m3/kg above 5.5 m, but other magnetic properties, such as frequency-dependent magnetic susceptibility (χfd % and χfd), susceptibility of anhysteretic remanent magnetization (χARM), and saturation isothermal remanent magnetization (SIRM) did not show a similar degree of enhancement. The magnetic grain size indicators of χARM/χlf, χARM/SIRM, and χlf/SIRM all indicate a trend of increasing magnetic grain size from the 5.5 m to the top of section; however, the bulk sediment grain size decreases gradually within the same interval. The total organic carbon is very low (0.2–0.7%), and thus, it is unlikely that the sedimentary environment is sufficiently strongly reducing to lead to the dissolution of magnetic minerals. Therefore, we infer that the coarsening-upwards of the magnetic grain size, and the increasing magnetic susceptibility from 5.5 m, reflect the gradual preferential preservation of magnetic minerals, caused by the deepening of the lake. Thus, we interpret the magnetic record of the section as reflecting the gradual deepening of the late stage of Gega ice-dammed lake. Last, the abrupt disappearance of the lake may have resulted in an outburst flood.