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1

Petrophysical and geomechanical analysis to delineating reservoirs in the miocene Niger delta region of Nigeria

Ojo Odunayo Tope, Adeoye James Adejimi, Okoli Emeka Austin, Emegha Joseph Onyeka

Geoinformatica Polonica

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2023

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T. 22

105--121

EN

The application of various petrophysical and elastic metrics has advanced reservoir characterization and provided critical geological formation information. Porosity declines with depth, according to sonic, neutron, and density logs. Lithology, pressure, and hydrocarbons all contribute to this. Formation resistivity and fluid saturation are used to identify hydrocarbon-bearing zones. Because oil and gas are non-conductive, hydrocarbon-containing rocks are more resistant than water. In lithological categorization, gamma logs and the Vp/Vs ratio have helped classify reservoirs as Agbada Formation sand-shale reservoirs. Reservoir elastic characteristics, specifically sandstones, have been studied at various depths. These discoveries have an impact on their brittleness, strength, and failure risk in a variety of scenarios. Hydrocarbon accumulation has been influenced by diagenetic compaction equilibrium in pressure-exposed shale source beds. The research advances our understanding of the geological formations of the Niger Delta and gives practical insights for exploration and production. Decisions on oil and gas are based on hydrocarbon reservoir assessments at various depths, including porosity, fluid saturation, and lithology. Well logs from Wells B001, B002, and B003 revealed the diverse properties of several Niger Delta reservoirs. These discoveries have benefited hydrocarbon exploration and production decision-making significantly.

PL

Charakterystykę zbiorników wodnych poszerzono dzięki różnym pomiarom petrofizycznym i pomiarom elastyczności, dostarczając wartościowych informacji o formacjach geologicznych. Określenia porowatości przy użyciu zapisów dźwięku, badania neutronów oraz gęstości wykazały wyraźną tendencję do zmniejszania się porowatości wraz z głębokością. Przyczynia się do tego litologia, ciśnienie i obecność węglowodorów. Strefy węglowodoronośne są identyfikowane przez korelację pomiędzy tworzeniem się oporności a nasyceniem skał węglowodorami. Wyższa oporność skał nasyconych węglowodorami wynika ze złego przewodnictwa ropy naftowej i gazu, w porównaniu z wodą. Klasyfikacja litologiczna na podstawie zapisu gamma i ilorazu Vp/Vs doprowadziła do głębszego zrozumienia składu złóż, klasyfikując je jako złoża piaskowo-łupkowe formacji Agbada. Elastyczne właściwości złóż, szczególnie piaskowców, wykazały ważne korelacje związane z głębokością, która ma wpływ na kruchość złóż, ich odporność oraz podatność na zniszczenie w różnych warunkach. Obserwowana w złożach łupkowych pod ciśnieniem równowaga ścisłości diagenetycznej odegrała znaczącą rolę w akumulacji węglowodorów. Wyniki badań nie tylko przyczyniają się do zrozumienia formacji geologicznych w rejonie delty rzeki Niger, ale również dostarczają podstaw do przedsięwzięć związanych z poszukiwaniem i eksploatacją złóż. Charakterystyka złóż węglowodorowych na różnych głębokościach i ich cechy, takie jak porowatość, nasycenie płynem i litologia, przyczynią się do podejmowania decyzji w przemyśle naftowo-gazowym. Analiza danych z odwiertów B001, B002 oraz B003 pozwoliła na znalezienie cech charakterystycznych dla wielu złóż w rejonie delty Nigru, dostarczając wartościowych informacji dla podejmowania decyzji dotyczących poszukiwań i wydobycia węglowodorów.

2

Forecasting the Natural Frequency of the Brake Disccasting

Zyska Andrzej, Bieroński Mariusz

Archives of Foundry Engineering

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2023

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Vol. 23, iss. 4

87--92

EN

The paper presents the results of calculations and measurements of the first natural frequency of castings of solid and ventilated brake discs made of gray cast iron of the EN-GJL-200 class. The tests were carried out for three types of chemical composition, taking into account the permissible minimum and maximum content of alloying elements. Numerical simulations of natural vibrations were carried out on the basis of our own production material databases. To determine the elastic properties of cast iron, the ultrasonic method with the measurement of the propagation velocity of longitudinal and transverse waves was used. Measurements were made directly on casts of raw discs of various thicknesses. The values of Young's modulus and Poisson's number calculated from ultrasonic measurements were used to define the stiffness matrix in the equilibrium equation, which is solved by the solver of the MSC Nastran program. A high compatibility between the results of numerical simulations and the results of experimental FRF frequency analysis was obtained. The differences between the calculated and actual values were at the level of several hertz, while the estimated average error of numerical simulations was 0.76%. It was also found out that cast iron melts for brake discs must be subject to strict control in terms of chemical composition. Slight deviations of the eutectic saturation coefficient from the optimal value cause a significant change in the first natural frequency of the brake discs, regardless of their geometry.

3

Surface characterization of the raw and cooked bovine cortical metatarsal bone

Petrovic Bojan B., Kojic Sanja, Peric Tamara O., Šipovac Milica, Lazarevic Jovana, Stefanovic Sofija, Stojanovic Goran

Acta of Bioengineering and Biomechanics

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2019

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Vol. 21, no. 1

13--21

EN

The purpose of this study was to quantify the elastic properties and evaluate microscopical features of raw and boiled metatarsal bovine bone. Methods: The elastic modulus, hardness and microscopic surface of raw and cooked bovine metatarsal bone have been investigated using nanoindentation, SEM/EDX and Panasis microscope. Results: Regarding raw bovine bone, the average elastic modulus was 30.515 ± 6,769 GPa, while the average hardness was 0.5683 ± 0.211 GPa. When it comes to boiled bone corresponding values were 22.298 ± 7.0303 GPa and 0.408 ± 0.199 GPa, respectively. The values for investigated parameters were significantly higher ( p < 0.05) in raw bone specimens. Elastic modulus significantly correlated with hardness ( p < 0.05). EDX analysis revealed significant decrease in wt% of oxygen in boiled samples ( p < 0.05) No significant differences could be observed in SEM images particularly when analysing in smaller magnifications. Using higher magnification, additional branching of the existing voids as well as discrete reorganization and smoother edges of nutrient canals could be observed. The surface of boiled specimens was without the presence of crusts and layering, and no microscopical evidence of structural damage could be observed. Conclusions: This study provides detailed analysis of hardness, elastic modulus of raw and cooked bovine bone and their relation and changes during exposure to temperature. These results of elastic moduli and hardness could be comparable to similar studies of bovine and human bone tissue, but the careful analysis of experimental design, type of the bone as well as limitations of the employed techniques must be carried out before interpolation of the results to other theoretical, clinical, biomaterial and archeological studies.

4

Influence of the variability of the elastics properties on plastic zone and fatigue crack growth

Kebir T., Benguediab M., Imad A.

Mechanics and Mechanical Engineering

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2017

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Vol. 21, nr 4

919--934

EN

Several theoretical models have been proposed to predict the fatigue crack growth range (FCGR) process using solid mechanics, based theoretical tools and basic or fundamental mechanical properties. Moreover crack growth is linked to the existence of a plastic zone at the crack tip when the formation and intensification are accompanied by dissipation of energy. The overall objective of the present research is to develop, verify, and extend the computational efficiency of the model for fatigue crack growth range (FCGR) function by elastic properties, cyclic hardening and celebrated Paris law. The influence of the variability to elastic properties (Young’s modulus E, tensile strength e and cyclic hardening exponent n’) is a necessary analysis in this work. The predictions of the proposed model were compared with experimental data obtained by [1].

5

Influence of the Rigid Element Area on the Compression Properties of Knitted Orthopaedic Supports

Alisauskiene D., Mikucioniene D.

Fibres & Textiles in Eastern Europe

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2012

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Vol. 20, no. 6A (95)

103--107

EN

This study attempts to investigate the influence of the area of a rigid element integrated into a knitted orthopaedic support on its elasticity. Usually researches analyse compression and other properties of compressive stockings and do not investigate the influence of non-textile parts used in knitted orthopaedic supports. The main goal of this paper was to investigate the influence of the surface area of the rigid element on the elasticity of a knitted orthopaedic support. It was found that the compression of the support increases depending on the area of the rigid element in the knitted support. The rate of influence of the rigid area on compression properties rises with an increase in the elongation value.

PL

W artykule przedstawiono badania nad wpływem powierzchni sztywnego elementu umieszczonego w dzianej strukturze uciskowej na właściwości elastyczne produktu. Zazwyczaj badania nie uwzględniają wpływu sztywnych elementów związanych z produktami ortopedycznymi oraz ich wpływu na elastyczność produktu. Stwierdzono, że ucisk wzrasta w zależności od powierzchni zastosowanego elementu sztywnego, a wpływ element sztywnego wzrasta wraz z wydłużeniem.

6

Morphology-based prediction of elastic properties of trabecular bone samples

Cosmi F.

Acta of Bioengineering and Biomechanics

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2009

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Vol. 11, nr 1

3-9

EN

Morphological characteristics of the trabecular structure, identified by micro-tomography, can be quantified by volume fraction and second-order fabric tensors. These parameters have been proved to be related to bone structural properties but the formulations so far developed between volume fraction, fabric and elastic properties are bone specific and the coefficients found for one bone are not directly applicable to other bones. In this work, a general relationship was determined that links volume fraction and Mean Intercept Length (MIL) to the trabecular structure stiffness as computed by means of numerical models on which compression tests are simulated. Preliminary results obtained for three pig and two rat bone structures show that, for the pooled data set, the model could predict approximately 99% of the variation of the numerically computed elastic moduli.

7

Molecular auxetics

Wojciechowski K. W.

Vibrations in Physical Systems

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2006

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Vol. 22

49--52

8

Effective elastic properties of periodic fibrous composites. Limit cases. Applications to porous and nonlinear materials

Bravo-Castillero J., Guinovart-Diaz R., Sabina F. J., Valdiviezo-Mijangos O. C., Sabina-de-Lis J. C.

Computer Assisted Mechanics and Engineering Sciences

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2006

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Vol. 13, No. 2

305-322

EN

The goal of this contribution is to provide, based on the asymptotic homogenization method, helpful exact formulae to compute the overall stiffnesses and engineering moduli of a transversely isotropic two-phase fibre reinforced composite with isotropic constituents. Comparison of the exact solution with known bounds is shown. In certain cases a bound is very close to the exact solution over a large interval. The bound then could be used as a good approximation to the exact solution. The exact formulae explicitly display Avellaneda and Swart's microestructural parameters, which have a physical meaning, and provide formulae for them. Hill's universal relations follow from the formulae. Limiting cases of rigid and empty fibers are included. An application of these results to improve bounds for the effective energy density of nonlinear dielectric fibrous composites is shown. Another application is related to bone poroelasticity.

9

The influence of chemical composition of amide block on the thermal properties and structure of terpoly(ester-b-ether-b-amide) elastomers

Ukielski R., Piątek R.

Polimery

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2003

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T. 48, nr 10

690-694

EN

Multiblock terpolymers-(PBT-b-PTMO-b-PA12,10)(n)- constituting the polymer systems, in which one of the three blocks (PBT) does not dissolve in PA12,10 block (hard phase) and, depending on its molecular weight is slightly soluble in PTMO block (soft phase), have been obtained. The DSC method was applied to investigate the thermal properties of these polymers and it was found that PBT block acts as an element that produces stiffness of -(PBT-b-PTMC-b-PA12,10)(n)- structure. Thus, this block causes deterioration of the elastic properties and leads to the formation of terpolymers showing the features of reinforced plastics. The terpolymers were compared with the previously described [5] -(PBT-b-PTMO-b-PA12)(n)-. They are elastomers when the rigid PBT block's polymerization degree is in the range 4-7. Such a block the rigid PBT block - dissolves in the hard phase of PA12 blocks and partly dissolves in the soft phase. So, it was found that even a small change in the chemical structure of the amide block influences significantly on the structure, phase separation and the properties of terpolymers. An analysis of the thermal properties of -(PBT-b- PTMO-b-PA12,10)(n)- confirms an argument that the block terpolymers show good elastic properties only in case when one of the blocks partly dissolves in the phases formed from the remaining blocks.

PL

Wpływ budowy chemicznej bloku amidowego na właściwości termiczne i strukturę elastomerycznych trójblokowych terpolimerów poli(estro-fc-etero-fc-amidowych) (/. ang.). Otrzymano multiblokowe terpolimery -(PBT-b-PTMO-b--PA12,10)n- (tabela 1) stanowiące układy polimerowe, w których jeden z trzech bloków (PBT) nie rozpuszcza się w fazie bloków PA12,10 (twardej) oraz, w zależności od swojego ciężaru cząsteczkowego, rozpuszcza się tylko nieznacznie w fazie bloków PTMO (miękkiej). Metodą DSC zbadano właściwości termiczne tych terpolimerów (rys. 3 i 4). Pozwoliło to na stwierdzenie, że blok PBT działa w takim układzie usztywniająco, naruszając właściwości elastyczne i umożliwiając w ten sposób uzyskanie tworzyw konstrukcyjnych o cechach polimerów wzmocnionych. Terpolimery porównano z opisanymi wcześniej [5] terpolimerami -(PBT-b-PTMO-b-PA12)n-. Są one dobrymi elastomerami wówczas, gdy zawarty w nich blok sztywny PBT ma stopień polimeryzacji w przedziale 4-7 (tabela 2, próbki 2 i 3 z serii I). Taki blok rozpuszcza się w twardej fazie bloków PA12 i częściowo rozpuszcza się w fazie miękkiej. Stwierdzono zatem, że nawet mała zmiana w budowie chemicznej bloku amidowego w istotny sposób wpływa na strukturę, rozdział faz i właściwości terpolimerów (tabela 2, rys. 1-4). Chcąc więc uzyskać korzystne właściwości użytkowe należy stosować w układach trójskładnikowych przynajmniej jeden składnik zdolny do rozpuszczenia się w pozostałych składnikach.