Due to methodological changes in the work of the Sakhalin Branch of the Federal Research Center
“Geophysical Survey of the Russian Academy of Sciences” (SB FRC GS RAS), it became necessary to clarify
the transition relationships between the energy characteristics of earthquakes in the Sakhalin region used for the
magnitude unification of the catalog. To obtain the transition relationships, a sample for the period from 2017 to
October 2024 was used from the database of the “Yuzhno-Sakhalinsk” regional information processing center,
which is a part of the SB FRC GS RAS. Using the generalized orthogonal regression method, the relationships
linking the magnitude of crustal (h less then 40 km ) earthquakes ML and the energy classes KР and KC were calculated,
as well as the magnitudes ML and MPVA separately for crustal and deep-focus (h = 250–600 km) earthquakes in
the region. The relationship between ML and the magnitude of the Japan Meteorological Agency Mj was also
obtained. It was revealed that for shallow Sakhalin earthquakes Mj ≈ ML; for deep-focus earthquakes, an
underestimation of the magnitude ML relative to Mj was noted. As the observational data accumulates, it is
assumed that the obtained relationships will be refined.
Evan Rosyadi Ogara, Tri Wahyuni, Al Hussein Flowers Rizqi
Coal is a deposit of organic matter derived from plant remains that have undergone diagenesis process to form a coal seams. This study aims to determine the impact of intrusion on the physical and chemical characteristics of coal. The location of this research is in the Air Laya mining area, PT Bukit Asam Tbk, Tanjung Enim, South Sumatra and is part of the South Sumatra Basin which is well known as one of the coal bearing formation areas. Four (4) coal samples were analysed including proximate analysis, total sulphur content, and calorific value to measure moisture content, volatile matter, fixed carbon, ash content, and calorific value of the coal. Petrology and well log analysis was used to determine lithology and regression analysis was used to assess the effect of intrusion on coal characteristics. The results of the coal analysis in the research area reveal significant differences between coal samples located near the intrusion and those farther away. Coal located near the intrusion exhibits black colour, vitreous and conchoidal fracture. In contrast, coal farther from the intrusion shows a dull, blackish-brown, brownish streak, and uneven fracture. Coal near the intrusion shows lower moisture (1.5–1.7%) and volatile matter (17–25%), but higher ash content (7.9–8.2%), fixed carbon (67–73%), calorific value (7700–7968 kcal/kg), and sulphur (0.7–0.8%). In the other hand, coal farther from the intrusion has higher moisture and volatile matter, but lower fixed carbon, calorific value, and sulphur. The findings conclude that proximity to intrusion increases fixed carbon and calorific value but also raises sulphur levels, which may pose environmental and operational concerns.
Abstract The change of fracture propagation direction caused by stress interference between fractures is one of the main reasons that affect shale gas productivity. Natural fractures will be damaged by the induced stress, and the induced stress field produced by natural fracture damage will in turn affect the propagation of hydraulic fractures. Previous studies usually ignored the impact of stress field variation caused by natural fracture damage, leading to inaccurate fracture propagation simulation results. A new model for simulating hydraulic fracturing-induced stress field is established with consideration of the influence of natural fracture damage. Then, the natural fracture-induced stress is analyzed in open and closed fracture states. Through superposition of stress fields of natural fractures and hydraulic fractures, the interaction among open and closed natural fractures, reservoir and hydraulic fracture, and the corresponding fracture property evolution are studied. The results demonstrate that induced stress is not affected by elastic modulus and Poisson's ratio of the rock. The induced stress difference at the fracture tip is proportional to the net pressure and the length of hydraulic fractures. The results provide guidance for the optimal design of fracturing. When the deflection angle of hydraulic fracture is less than 90°, the maximum induced stress difference at the fracture tip decreases with the reduction in the deflection angle. When the deflection angle of hydraulic fracture is smaller than 90° or the deflection angle of natural fracture is smaller than 45°, the steering of hydraulic fracture is less hindered, which is beneficial to the formation of complex fracture network.
L. Monasterio-Guillot, L. Crespo-Lopez, I. Gonzalez-Perez
et al.
The Alcazaba of Almería (Spain) is one of the most important Arabic fortresses of the Iberian Peninsula archaeological record. It is located in the south of Spain, on the Mediterranean coast, and its construction dates back to the late 10th century. It consists of three enclosures, two of which belong to the Andalusian period, while the last one dates from the 16th century. However, very few materials’ studies have been performed in this complex, despite the incomparable historic relevance. In this study, we present an extensive mineralogical and physical-chemical characterization of the construction materials of this site, divided in mortars, earthen materials and bricks. We provide an unprecedent scientifical-technical study of the building materials of this fortress, so as to understand the building techniques used and the causes of deterioration. All collected samples were analyzed by means of X-ray diffraction, scanning electron microscopy, optical microscopy thermogravimetric analysis and stereo-zoom microscopy. Our results reveal that main phases used for construction materials on this site were Ca and Mg-carbonates, accompanied by Fe-Ca-Mg silicates. Mortars showed a carbonate-binder composition with non-hydraulic nature whereas calcination of raw materials occurred below 800 ºC due to the permanence of dolomite. Furthermore, we demonstrated that the construction materials from the Alcazaba suffered such relevant damages due to the precipitation of salts (i.e., gypsum and halite) caused by coastal environment, key information for future archaeological restoration work in this highly significant location. We show that, in mortars and earthen materials, halite nucleates in fractures and dissolution pits exerting a crystallization pressure ∼ 100 MPa to cause fracture. Furthermore, calcium and magnesium silicate hydrates were observed confirming some pozzolanic properties. Finally, the bricks studied here demonstrated that firing T maximum of 700 ºC due to the presence of carbonates. This work opens new pathways to develop specific consolidation methods of materials and structural elements, as well as to ensure adequate restoration and conservation, of similar archaeological sites in coastal-related environments
Materials of engineering and construction. Mechanics of materials
Abstract The mechanical properties of deep volcanic reservoir rocks are complex and the brittleness characteristics are not clear. In order to study the brittleness characteristics of deep volcanic rocks, triaxial compression tests and XRD tests under different confining pressures were carried out to study the brittleness characteristics of deep volcanic rocks. Three methods were used to evaluate the brittleness of volcanic rocks from different sides: the brittleness evaluation method based on stress–strain curve characteristics (BI1), the brittleness evaluation method based on energy dissipation (BI2) and the brittleness evaluation method based on mineral composition (BI3). The three methods showed that the brittleness index of volcanic rocks decreases with the increase in confining pressure, and the higher the depth of volcanic rocks, the lower the brittleness. On the basis of previous studies, an improved brittleness evaluation method based on internal friction Angle was proposed, and the obtained evaluation results were almost consistent with the results obtained by the brittleness evaluation method based on stress–strain curve characteristics (BI1) and the brittleness evaluation method based on energy dissipation (BI2), indicating the feasibility of the improved brittleness evaluation method. The brittleness characteristics of deep volcanic rocks are clearly defined to provide reference for the exploration and development of deep volcanic rocks reservoir.
Nawfal Adnan Dahham, Nabeel K. Abbood, Seyednooroldin Hosseini
et al.
Abstract The effects of the main components of crude oil, especially resin and asphaltene fractions, are essential concerns for efficient enhanced oil recovery (EOR) processes, especially during chemical injection processes. This importance comes from the nature of these two fractions which can act as surface active agents with undeniable effects on the used chemical for interfacial tension (IFT) reduction and wettability alteration. In this way, the effect of silicon oxide nanoparticles (SiO2-NPs) concomitant with two ionic liquids (ILs), namely 1-dodecyl-3-methyl imidazolium chloride ([C12mim][Cl]) and 1-octadecyl-3-methyl imidazolium chloride ([C18mim][Cl]), is investigated on the wettability alteration and IFT reduction using synthetic oils prepared by dissolving the extracted resin and asphaltene fractions with a concentration of 1–5 wt%. The measurements reveal that the effect of resin fraction is less than the asphaltene fraction for IFT reduction and wettability alteration. The sole presence of resin fraction reduces the IFT from 35.3 to 28.3 mN/m as the concentration is increased from 1 to 5 wt%, while a similar increase in the asphaltene fraction concentration reduces the IFT from 35.5 to 19.1 mN/m. Besides, the results reveal that the presence of [C12mim][Cl] in the range of 0–1000 ppm leads to a reduction in IFT from its maximum value of 35.3 to 0.81 mN/m, while in the case of [C18mim][Cl] with similar concentration variation, IFT is reduced from 35.3 to 0.7 which means the better effect of IL with longer chain length on the IFT reduction. Further analysis revealed that the effect of asphaltene fraction on the IFT is higher than resin fraction since the minimum IFT value was observed for [C18mim][Cl] with the value of 0.58 mN/m, while the contact angle (CA) values revealed revers effect for asphaltene fraction compared with the resin fraction. In general, regardless of the used IL, it seems that ILs leading to better wettability conditions which are crucial for EOR purposes and even better IFT values that can mobilize the trapped oil toward production points. Besides, further measurements revealed a positive effect of SiO2-NPs concomitant with the ILs to move the wettability toward the strongly water-wet condition with CA values of 29.2° and 28.3° for SiO2-NPs concentration of 1000 ppm and 1000 ppm of concentration for [C12mim][Cl] and [C18mim][Cl], respectively, for resinous synthetic oil (RSO) (5 wt%) while no meaningful effect regarding the SiO2-NPs presence at the different concentrations (100–2000 ppm) is found on the IFT reduction. A similar trend is observed for asphaltenic synthetic oil (5 wt%)/aqueous solution (SiO2-NPs with a concentration of 1000 ppm + ILs with a concentration of 1000 ppm) which reduces the CA to 26.3° and 37.8° for [C12mim][Cl] and [C18mim][Cl]), respectively.
Nabeel K. Abbood, Nawfal Adnan Dahham, Mohammad Assarehzadegan Dezfouli
et al.
Abstract During the past years, the usage of new oil recovery methods known as enhanced oil recovery methods is increasing because of energy consumption rate enhancement and reservoir pressure depletion. Unfortunately, since most of the investigations were focused on crude oil, it is hard to find a generalized pattern of interfacial tension (IFT) and wettability change for different crude oils because of its complicated composition. So, it is necessary to examine the effect of specific fractions of crude oil especially resin and asphaltene fractions on the IFT and wettability alteration using systematic investigations. Although a limited number of investigations examined the interactions between these specific fractions and salts, there are no systematic reports respecting the possible interactions between asphaltene and resin fractions in the presence of alkaline and surfactant. So, in the first stage, the impact of dissolving asphaltene (0–9 wt%) in the toluene was investigated on the IFT reduction which revealed a decrease in IFT value from 34.8 to 23.3 mN/m as the asphaltene concentration was increased. Further experiments showed that the presence of MgCl2 and NaCl with a maximum concentration of 5000 ppm led to a reduction in IFT to a minimum value of 18.3 and 17.3 mN/m for NaCl and MgCl2, respectively, which means the higher impact of MgCl2 on the IFT reduction. After that, the selected optimum concentrations of MgCl2 and NaCl (5000 ppm) were used in the rest of the experiments in which the effect of resin fraction and other chemicals including sodium dodecyl benzenesulfonate (SDBS) and NaOH concentrations was examined on the IFT reduction and rock wettability. According to the obtained results, it was possible to reach the minimum IFT value of 0.08 mN/m, which is several orders lower than the original IFT value of the binary system without the chemicals using the optimum chemical formulation obtained by mixing proper concentrations of SDBS, NaOH, MgCl2, and NaCl. Moreover, the obtained optimum formulations were used through core flooding experiments which revealed the possibility of increasing the oil recovery to a maximum value of 10.1% based on the original oil in place.
The paper presents the results of studying soil lichens in areas of thermal habitats on the Kuril Islands, including the features of lichen distribution on the isles. Totally four species of epigeic lichens were found when studying the thermal fields on Kunashir and Iturup isles: Cladonia graciliformis, C. granulans, C. vulcani, and C. furcata. First three species are closest to active fumaroles and have the highest rates of occurrence frequency for these habitats.
In the Velika ledena jama v Paradani, in the karstic blowholes on the slopes of Smrekova draga and in the nearby dolines I measured and interpreted air temperatures and the effect of the summer outflow of cold air from them into the surrounding area. In winter, cold air enters the cave, radically cooling the entrance part of the cave, where for this reason there is permanent cave ice. The summertime circulation is reversed: emerging from the inner part of cave, which has an average temperature of around 4° C, is air which only when it transits through the sub-cooled entrance part is then cooled to around 1° C. This air comes to the surface and in the hollow at the cave entrance maintains a distinct thermal inversion during the warm part of the year. There is a similar air circulation and similar development of annual temperatures observed at the vents, where cave air emerges through rubble spread over cave entrances on slopes or at the bottom of dolines. The stable summer air temperatures of around 1° C in the vents where I conducted measurements indicate that underneath them there is also permafrost or sub-cooled rock and permanent ice. This is created and preserved, just like in the caves, due to the advection of cold air in winter. In Trnovski gozd, such karstic permafrost is found at an altitude of 1,100 m above sea level. The outflow of cold air from the vents in the summer, just like inside the cave, causes a distinct thermal inversion in dolines on the surface.
Tashina area, as a part of the Sanandaj- Sirjan magmatic- metamorphic Zone, located 10 kilometers north of Serkan city and on the southern slope of Kuhe- Gavbar. The most important geological unit is the porphyroid granite belonging to the Middle Jurassic. Tourmaline is observed as massive in pegmatites and as quartz tourmaline veins within the host granodiorite. The massive tourmalines are spherical, elliptical, elongated, and radial, and sometimes it is so abundant that it can be as the tourmalinite type. Optically, the massive tourmalines show brown- green in color, sometimes very intense intefrance whereas the tourmaline veins are brown- green and blue (indicolite). Indicolite related to the tourmaline delayed phase and is newer than brown- green tourmalines.The studied tourmalines are Fe- rich and schorl type, base on EPMA data as well as several diagrams. The tourmaline in the quartz- tourmaline veins are the vacancy type while the second type is often alkaline with tendency to this group. Euhedral forms and the lack of chemical zoning, with high Al and Fe/Fe+Mg contents, deficiency in X sites, and plentiful tourmaline in host granitic rock which is Li poor are all indicative of the magmatic origin of tourmaline enriched in B. The presence of Ba, Eu, Nb, and Sr negative anomalies in the studied samples and the separation of plagioclase and K- feldspar can be accounted as important factors in magmatic evolution of the studeid rocks. Overall, the results of petrographic studies are well in accordant with trace and REE geochemistry data.
Abstract This study aimed to prepare a chelating agent SA-20 using diethylenetriaminepentaacetic acid (DTPA) and low molecular weight sodium polyacrylate raw material for the removal of barium sulfate (BaSO4) scale. The morphology of the resulting chelating agent was characterized by scanning electron microscopy. The BaSO4 scale removal ability of SA-20 was comprehensively evaluated by the dissolving ability, particle size analysis, corrosion performance, and fracture conductivity before and after the scale removal. The results showed that the SA-20 has a good BaSO4 scale removal ability due to the chelation, lattice distortion, and dispersion of DTPA and low molecular weight sodium polyacrylate.
The new railway line between Divača and Koper/Capodistria in south-western Slovenia is being built, a part of which crosses the southern outskirts of the Classical Karst plateaux. It will run through two tunnels, the northern tunnel T1 (6.7 km long) and the southern T2 (6 km long), which partially cross karst aquifer system. A multi-tracer test with injections of fluorescent dyes uranine and naphthionate, bypassing the karst vadose zone, was carried out to define the directions and dynamics of the underground water flow. The main goals were better understanding of the complex hydrogeological conditions in the area and assessment of possible environmental impacts on the nearby water sources. With tracing of uranine injected into a nearby cave stream, the direction of flow from the northern T1 tunnel mainly towards the Reka-Timavo aquifer system and further towards the Timava/Timavo springs was proved. The peak velocities, as determined from the peaks of the tracer breakthrough curves, range from 29 m/h to 36 m/h. Through the wider and well-connected conduits of the Reka-Timavo system, the peak velocities can reach up to 88 m/h. The recovery of uranine in an intermediate cave, i.e., Jama 1 v Kanjaducah, amounted to approximately 74 %. The northern section of the southern T2 tunnel is a part of a wider bifurcation zone between the Osapska Reka and the Boljunec/Bagnoli springs, where peak flow velocities between 10 and 13 m/h have been determined by tracing of naphthionate injected into a borehole located in the line of the planned tunnel. It has been estimated that about 25 % of the injected naphthionate flew out through the Osapska Reka spring and about 5 % through the Boljunec/ Bagnoli springs. Based on this research, proper monitoring of any potential negative impacts of the new railway line will be made possible. The study presents an approach to better planning of hazard control of traffic routes in complex and highly karstified rock settings.
Abstract This study investigates flow behavior in the volatile oil reservoirs with two‐phase flow around the wellbore and the application of two-phase pseudo-pressure function for well test analysis in such volatile oil reservoirs. To this end, flow behavior and saturation profile of the volatile oil reservoirs with flowing bottom-hole pressure below the bubble point pressure are investigated using a synthetic reservoir model. Subsequently, well test behavior of this reservoir in drawdown and buildup tests are examined. Finally, the application of two-phase pseudo‐pressure concept is examined for analyzing well test data of the volatile oil reservoir. It is shown that two-phase flow near the wellbore causes a composite behavior in well test data with decreasing mobility during drawdowns and increasing mobility during buildups. Moreover, employing normalized two-phase pseudo-pressure function introduced in this study is found to be a suitable method for well test analysis in volatile oil reservoirs. Using the aforementioned method, effective permeability and wellbore skin are estimated by eliminating the effect of gas saturation on the well test results.
J. N. Sutton, G. F. de Souza, M. I. García-Ibáñez
et al.
<p>The stable isotope composition of dissolved silicon in seawater
(<i>δ</i><sup>30</sup>Si<sub>DSi</sub>) was examined at 10 stations along the GEOVIDE
section (GEOTRACES GA-01), spanning the North Atlantic Ocean
(40–60° N) and Labrador Sea. Variations in
<i>δ</i><sup>30</sup>Si<sub>DSi</sub> below 500 m were closely tied to the distribution
of water masses. Higher <i>δ</i><sup>30</sup>Si<sub>DSi</sub> values are associated with
intermediate and deep water masses of northern Atlantic or Arctic Ocean
origin, whilst lower <i>δ</i><sup>30</sup>Si<sub>DSi</sub> values are associated with
DSi-rich waters sourced ultimately from the Southern Ocean. Correspondingly,
the lowest <i>δ</i><sup>30</sup>Si<sub>DSi</sub> values were observed in the deep and
abyssal eastern North Atlantic, where dense southern-sourced waters dominate.
The extent to which the spreading of water masses influences the
<i>δ</i><sup>30</sup>Si<sub>DSi</sub> distribution is marked clearly by Labrador Sea
Water (LSW), whose high <i>δ</i><sup>30</sup>Si<sub>DSi</sub> signature is visible not
only within its region of formation within the Labrador and Irminger seas,
but also throughout the mid-depth western and eastern North Atlantic Ocean.
Both <i>δ</i><sup>30</sup>Si<sub>DSi</sub> and hydrographic parameters document the
circulation of LSW into the eastern North Atlantic, where it overlies
southern-sourced Lower Deep Water. The GEOVIDE <i>δ</i><sup>30</sup>Si<sub>DSi</sub>
distribution thus provides a clear view of the direct interaction between
subpolar/polar water masses of northern and southern origin, and allow
examination of the extent to which these far-field signals influence the
local <i>δ</i><sup>30</sup>Si<sub>DSi</sub> distribution.</p>
Krstekanić Nemanja, Stojadinović Uroš, Kostić Bojan
et al.
Fault-related folds and hanging-wall structures reflect the geometry of the
main thrusts in foldthrust belts. The results of the structural analysis of
the Supragetic Unit metamorphic basement in eastern Serbia at map-, outcrop-
and thin-section scale, and its importance for the late Early Cretaceous
nappe-stacking are presented in this paper. The Supragetic Unit metamorphic
basement includes various volcano-sedimentary rocks of Ordovician-Silurian
protolith age. They were metamorphosed to the low greenschist facies with
temperatures reaching 300-350°C and pressure reaching 0.3-0.5 GPa. The
microscale studies show that quartz and albite demonstrate dominantly
bulging and locally subgrain rotation recrystallisation, while chlorite,
sericite and muscovite define spaced to continuous foliation recognised both
at the outcrop- and the thin-section-scale. The statistical analysis based
on the available map data shows low- to high-angle west-dipping foliation
which is interpreted as an indicator of flat-ramp geometry of the Supragetic
thrust, rather than east-vergent tight to isoclinal folding. At the
thin-section scale ductile to semi-ductile C’-S structures indicate top to
ESE thrusting. Subsequent kinking, recognised both at the outcrop- and the
thin-section-scale, deform the older foliation. Those kink bands are the
result of WNW-ESE to NW-SE compression and could represent the later stage
of a continuous deformation event during which C’-S structures were formed.
The youngest, brittle deformation is represented by subvertical joints with
no offset recognised in thin-sections. The structural characteristics of the
Supragetic Unit low-grade metamorphic basement in the studied areas,
combined with tectonothermal events recognised elsewhere in Dacia mega-unit,
could imply a possible initiation of the late Early Cretaceous
nappe-stacking in the ductile to semi-ductile/semi-brittle domain. [Project
of the Serbian Ministry of Education, Science and Technological Development,
Grant no. OI176015 and Grant no. OI176019]
Maja Ivanić, Neda Vdović, Sandra de Barreto
et al.
This paper comprises the research on the surface characteristics, the specific surface area (SSA), the cation exchange capacity (CEC) and the electrophoretic mobility (EPM) of the kaolin clays obtained from different naturally occurring pegmatite and granite deposits worldwide. Particularly the influence of the ancillary minerals on these properties was studied, as well as the diversity in morphological and structural characteristics of kaolinite in samples. The mineral composition and the morphology of the kaolin samples were investigated using X-ray diffraction (XRD) and field emission scanning electron microscope (FE-SEM), respectively. The SSA was determined by BET method, the CEC by ammonium selective electrode and the surface charge by EPM measurements. The results showed that the surface properties of the kaolin samples were strongly influenced by the presence of ancillary constituents, particularly smectite minerals. Their occurrence, even in trace amounts, significantly increased SSA and CEC values of the investigated samples. Most importantly, EPM measurements revealed that the character of the amphoteric surfaces of the dominant kaolinite mineral in samples was rescinded by the permanent pH-independent siloxane basal charge of smectite. The presence of ancillary smectites, characterized with the higher surface reactivity, hindered the surface properties of the prevailing kaolinite mineral in the kaolin clay deposits.
<p><a href="http://dx.doi.org/10.17014/ijog.vol1no1.20061a">http://dx.doi.org/10.17014/ijog.vol1no1.20061a</a></p><p>The Permian Mengkarang Coal Measures is situated in the middle part of Sumatera Island. Some fresh outcrop samples of the Permian Mengkarang coals have been analyzed both macroscopically and microscopically, to asses their depositional environment. On the basis of organic-petrological analysis, the coal seams show variation in the predominance of some macerals, indicating successions of environmental changes. The dominant maceral group is vitrinite, present in very low to very high values; whilst the minor one is inertinite showing low amount. Environmental information derived from the organic facies study shows that the coals were deposited in wet zone of mire, ranges from wet limnic-telmatic zone to telmatic wet forest swamp under rapid burial condition, due to rapid basin subsidence. The organic facies concept is thus applicable in basin studies context and has potential to become an additional tool for interpretation of depositional environment.</p> <p> </p> <p> </p>