Porosity Measurements Research Articles

Integrated controls of tectonics, diagenesis and sedimentation on sandstone densification in the Cretaceous paleo-uplift settings, north Tarim Basin

The densification mechanism of the Lower Cretaceous sandstone in the western Tabei Uplift is still unclear, restricting successful petroleum exploration and development. Seismic interpretation, thin sections observation, Field emission scanning electron microscope (FE-SEM) and cathodoluminescence (CL), porosity and permeability measurements, mercury injection porosimetry (MIP) are compiled in this study, to investigate the paleo-uplift and facies co-evolution, tight reservoir characteristics, and densification mechanism of the Lower Cretaceous sandstones around the paleo-uplift. Results indicate the sedimentary facies around the Xinhe and the Sandaoqiao uplifts were controlled by the decreasing geomorphic slope and rising lake level, their evolution exhibited difference. The Xinhe area developed a fan delta with a reducing distribution in region, while the sandaoqiao area transitioned from fan delta to beach bar, eventually developing a braided river delta. Reservoir physical properties are primarily influenced by intense compaction, calcite and clay cementation and weak dissolution. Severe calcite cementation, compaction and weak dissolution predominantly influence the physical properties of the beach bar. Moderate compaction, weak cementation and moderate quartz and feldspar dissolution are the key factors impacting the physical properties of braided river delta. Additionally, reservoir quality varies with sedimentary facies where the sandstones of the braided-river delta have the best petrophysical properties and pore connectivity than those of the fan delta and beach bar. Tectonic movements around the uplift affected the distribution of various sedimentary facies, which later governed the diagenesis processes pathways. Collectively, this study can serve as a valuable reference for exploration and development of clastic reservoirs in the Tabei Uplift and analogous reservoirs with a paleo-uplift context.

Shale primary porosimetry based on 2D nuclear magnetic resonance of T1-T2

Porosity, a key parameter in assessing the physical properties of shale reservoirs and the reserves, is of great significance to the selection and evaluation of shale sweet spots. There are many methods at present to characterize shale porosity, most of which are aimed at post-core cleaning shale, such as those involving helium and saturated fluid (namely liquid-involved porosimetry). However, due to the low efficiency of shale core cleaning and the possible damage to pore structure during the core cleaning process, it's hard to guarantee the accuracy of porosity measurement. In this regard, we resort to the two-dimensional (2D) nuclear magnetic resonance (NMR) technology of T1-T2 in characterizing the primary shale porosity with samples taken from pressure coring in the 4th member of Shahejie Formation (Sha 4 Member) in well Fanxie 184 in the Jiyang Depression. Moreover, comparative experiments of shale porosity measurement by three methods, namely the simultaneous distillation extraction (SDE), helium and fluid measurement, are carried out simultaneously. The results show that the values obtained by SDE, gas and liquid measurement are similar, which are about 0.6 times of 2D NMR porosimetry. Core cleaning efficiency tends to seriously affect the results involving gas and liquid. In addition, the core cleaning treatment is bound to change the shale pore structure, and this is especially true in clay which tends to swell; consequently, porosity results are to be distorted by gas and liquid methods. It is thereby recommended to utilize the 2D NMR technology to characterize the primary total porosity of shale samples without core cleaning. The effective porosity of samples from pressure coring is determined by T2 cutoff value of around 0.3 ms.

TiO2-PAA-SiO2 pearl chain blend modified polyvinylidene fluoride ultrafiltration membrane with excellent oil-water separation, anti fouling performance and durability

ABSTRACT In this work, a new type of composite nanoparticles, ‘pearl chain’, was developed by linking titanium dioxide and silicon dioxide by polyacrylic acid polymer chains, and the prepared TiO2-PAA-SiO2 composite nanoparticles were analysed by SEM, Fourier transform infrared spectroscopy, x-ray photoelectron spectroscopy and thermogravimetric analysis, zeta potential, x-ray diffraction, etc. The success of this work was verified by the successful linking of TiO2-PAA-SiO2 composite nanoparticles.TiO2-PAA-SiO2 composite nanoparticles were analysed to verify the successful attachment of pearl chains. The obtained TiO2-PAA-SiO2 were subsequently blended in different ratios to prepare polyvinylidene fluoride (PVDF) ultrafiltration membranes. The membrane performance was tested by porosity and water contact angle measurements, scanning electron microscopy, as well as experiments using bovine serum proteins and MTBE interception. The results showed that when a certain amount of TiO2-PAA-SiO2 was added, the surface wettability, porosity and permeability of the prepared modified composite membranes were significantly improved, and the BSA adsorption rate was increased from 71.59% to 80.86%, and the retention rate of MTBE was increased by 77%, in addition to showing a better anti-pollution effect (FRR: 91.07%). It was finally concluded that the prepared membranes embedded with 1.0 wt.% TiO2-PAA-SiO2 nanofillers showed good overall filtration performance, better contamination resistance and remarkable durability. The present work successfully demonstrated the feasibility of using polyacrylic acid chemical chains to connect nanoparticles with different functions to prevent particle loss and substantially enhance membrane performance, which is valuable for bridging connection of composite nanoparticles and exploring the development of high-performance ultrafiltration membranes.

Digital Cake Analysis: A Novel Coal Filter Cake Examination Technique Using Microcomputed Tomography

Filtration is crucial for separating solids and liquids in various industries. Understanding slurry properties and filter cake structures is essential for optimising filtration performance. Conventional methods focus on interpreting filtration data to improve the understanding of filtration mechanisms. However, examining fragile filter cakes is challenging, and current techniques often alter their structure. Conventional methods only provide an average representation of cake porosity, neglecting variations in porosity and pore distribution across the cake thickness. This study introduces the Digital cake analysis, a non-destructive technique for evaluating filter cake structure. Filtration experiments using a custom-built unit were conducted on coal slurries to obtain filter cake samples. X-ray-microcomputed tomography (µCT) imaging was utilized for cake analysis. Image enhancement techniques were employed to improve the quality of the µCT images. The enhanced images were segmented into three phases (resolved pore, subresolution pore, and solid phases) for quantitative analysis. This segmentation technique allocated partial pore volume to voxels in the subresolution phase based on their intermediate grey-scale intensity, enabling more accurate porosity calculations. Unlike conventional methods, this approach computed porosity values for resolved (100% void) and subresolution (partially void) pores. This image segmentation technique facilitated accurate computations of porosity, pore size distribution, and pore properties, significantly advancing the understanding of cake structures. Digital cake analysis produced porosity measurements similar to the experimental results.

THE SOIL CARBON STOCK IN THE TOURISM AREA OF GILI TRAWANGAN

This study aims to determine the distribution of carbon stocks in various land uses and total carbon stocks in the tourism area of ​​Gili Trawangan. This research was conducted in the Gili Trawangan area, Physics and Soil Conservation Laboratory, and Soil Chemistry and Biology Laboratory, Faculty of Agriculture, University of Mataram, in June-October 2022. The method used in this study was a descriptive method with a survey technique. The descriptive method can start with data collection, analysis and interpretation. Carbon in the soil in this study was obtained from the results of C-organic laboratory analysis (Walcky and Black) supported by measurements of soil unit weight (BV), soil porosity and soil texture. Meanwhile, aboveground carbon stocks were obtained through direct sampling in the field by measuring tree biomass. The results showed that the total carbon stocks in various land uses have different carbon stocks. The mixed garden had the highest carbon stock of 840.27 ton.ha-1, forest land of 83.76 ton.ha-1, and shrubs of 15.76 ton.ha-1, and the lowest carbon stock was a settlement of 3.01 ton. ha-1. Overall, carbon stocks in the tourist area of ​​Gili Trawangan are 942.8 ton.ha-1.

Deep learning image segmentation for the reliable porosity measurement of high-capacity Ni-based oxide cathode secondary particles

The optimization of geometrical pore control in high-capacity Ni-based cathode materials is required to enhance the cyclic performance of lithium-ion batteries. Enhanced porosity improves lithium-ion mobility by increasing the electrode–electrolyte contact area and reducing the number of ion diffusion pathways. However, excessive porosity can diminish capacity, thus necessitating optimizing pore distribution to compromise the trade-off relation. Accordingly, a statistically meaningful porosity estimation of electrode materials is required to engineer the local pore distribution inside the electrode particles. Conventional scanning electron microscopy (SEM) image-based porosity measurement can be used for this purpose. However, it is labor-intensive and subjected to human bias for low-contrast pore images, thereby potentially lowering measurement accuracy. To mitigate these difficulties, we propose an automated image segmentation method for the reliable porosity measurement of cathode materials using deep convolutional neural networks specifically trained for the analysis of porous cathode materials. Combined with the preprocessed SEM image datasets, the model trained for 100 epochs exhibits an accuracy of > 97% for feature segmentation with regard to pore detection on the input datasets. This automated method considerably reduces manual effort and human bias related to the digitization of pore features in serial section SEM image datasets used in 3D electron tomography.Graphical abstract

Alumina-Magnesia-Supported Ni for Hydrogen Production via the Dry Reforming of Methane: A Cost-Effective Catalyst System

5Ni/MgO and 5Ni/γAl2O3 are pronounced in the line of cheap catalyst systems for the dry reforming of methane. However, the lower reducibility of 5Ni/MgO and the significant coke deposition over 5Ni/γAl2O3 limit their applicability as potential DRM catalysts. The mixing capacity of MgO and Al2O3 may overcome these limitations without increasing the catalyst cost. Herein, a 5Ni/xMg(100 − x)Al (x = 0, 20, 30, 60, 70, and 100 wt. %) catalyst system is prepared, investigated, and characterized with X-ray diffraction, surface area and porosity measurements, H2-temperature programmed reduction, UV-Vis-IR spectroscopy, Raman spectroscopy, thermogravimetry, and transmission electron microscopy. Upon the addition of 20 wt. % MgO into the Al2O3 support, 5Ni/20Mg80Al is expanded and carries both stable Ni sites (derived through the reduction of NiAl2O4) and a variety of CO2-interacting species. CH4 decomposition at Ni sites and the potential oxidation of carbon deposits by CO2-interacting species over 5Ni/20Mg80Al results in a higher 61% H2-yield (against ~55% H2-yield over 5Ni/γAl2O3) with an excellent carbon-resistant property. In the major magnesia support system, the 5Ni/60Mg40Al catalyst carries stable Ni sites derived from MgNiO2 and “strongly interacted NiO-species”. The H2-yield over the 5Ni/60Mg40Al catalyst moves to 71%, even against a high coke deposition, indicating fine tuning between the carbon formation and diffusion rates. Ni dispersed over magnesia-alumina with weight ratios of 7/3 and 3/7 exhibit good resistance to coke. Weight ratios of 2/8 and 7/3 contain an adequate amount of reducible and CO2-interactive species responsible for producing over 60% of H2-yield. Weight ratio 6/4 has a proper coke diffusion mechanism in addition to achieving a maximum of 71% H2-yield.

Experimental and digital investigations of heterogeneity in lower cretaceous carbonate reservoir using fractal and multifractal concepts

Characterization and prediction of reservoir heterogeneity are crucial for hydrocarbon production. This study applies the multifractal theory using both numerical and experimental data to characterize quantitatively the heterogeneity of pore structures in Lower Cretaceous limestone reservoir from the United Arab Emirates. Fractal dimensions calculated from three dimensional digital images showed good correlation (R2 = + 0.69) with experimental high-pressure mercury injection (HPMI) measurements. Moreover, both experimental and numerical fractal dimensions correlate well with experimental HPMI porosity measurements. Multifractal parameters such as the non-uniformity degree of the pore structures Δα, the asymmetry degree in the vertical axis Δf(α), the concentration of pore size distribution α0 and the asymmetry degree in the horizontal axis Rd estimated from digital and experimental data correlated well and revealed ability to quantitatively describe samples heterogeneity. The ranges of digital and experimental multifractal parameters provided the means to differentiate between homogeneous and heterogeneous samples.

Development of a neutron probe to perform a combined measurement of uranium concentration and hydrogen porosity for mining applications

This work reports the development of a new neutron probe for mining prospection and exploitation. It allows a combined measurement of hydrogen porosity, based on the detection of neutrons backscattered by the geological formation, and of uranium concentration based on induced-fission prompt neutrons, with the Differential Die-away Technique. The probe includes a pulsed neutron generator and a single neutron counter embedded in a polyethylene block wrapped with cadmium, saving the place for a gamma-ray detector compared to usual porosity probes with two 3He counters. We first report design and feasibility studies using MCNP 6.2 simulations, showing the significant effect of hydrogen porosity on the uranium signal and the need for a combined interpretation. Then, we report laboratory experiments that validate the simulation methods of both the porosity and uranium useful signals, but also the active background due to 17O activation. Taking into account neutron absorbers in the sand of our testing system, like boron, lithium and gadolinium measured by ICP-MS, the simulated and experimental signals of prompt fission neutrons agree within +20 %. The relative effect of water, introduced in the central hole of our experimental system, is about 30 % on the backscattered neutron signal, in both simulation and experiment. Finally, the spatial sensitivity of the tool, which is maximal in front of the detector and extends to approximately 20 cm (FWHM) in the vertical axis, is well reproduced with MCNP.

Three‐dimensional stratigraphic architecture, secondary pore system development and the Middle Pleistocene transition, Sandy Point area, San Salvador Island, Bahamas

AbstractThe Bahamian Archipelago has been the subject of extensive studies of stratigraphy, carbonate island morphology and diagenetic overprinting for many decades. A recently‐acquired dataset comprised of high‐resolution light detection and ranging, tightly spaced cored boreholes with image logs, thin sections, porosity and permeability measurements, and isotopic geochemical analyses provides a unique opportunity to perform detailed sequence stratigraphic analysis. This multi‐faceted study first establishes a new high‐resolution sequence stratigraphic framework for the Sandy Point area of San Salvador Island, encompassing six unconformity bound sequences (exposure surfaces) representing varying lengths of missing time. The stratigraphically lowest sequence is Late Pliocene in age and is dominated by reef facies capped by an extensive laminar caliche that represents 1.5 million years of exposure. The overlying Early Pleistocene is split into two sequences, EP1 and EP2, which are both dominated by low‐energy subtidal facies. The upper three sequences are tied to the Marine Isotope Stage 11, 9 and 5e interglacials, and are distinctly different in facies composition and architecture, being dominated by higher energy facies distributed in a more complex mosaic. The new stratigraphic framework highlights significant changes in depositional style and facies architecture that can be linked to increasing sea‐level amplitude oscillations and greater climate gradient at the Mid Pleistocene Transition. The well‐constrained framework is then used to provide key context for observed complex diagenetic evolution through repeated sea‐level inundation and subaerial exposure. These results suggest that well‐developed subaerial exposure surfaces drive increases in non‐matrix features in the subsequent stratigraphic package following exposure as the well‐cemented exposure surface acts to concentrate fluid flow and dissolution. Integration of non‐matrix features within this framework highlights the importance of dissolution/cementation patterns on formation of these modified unconformity surfaces for focusing later meteoric diagenesis and creating enhanced fluid flow pathways for continued multicyclic diagenetic events.

A New Multi-Scale Method to Evaluate the Porosity and MICP Curve for Digital Rock of Complex Reservoir

The evaluation of rock porosity and the mercury injection capillary pressure (MICP) curve is fundamental for oil and gas exploration and production. Digital rock (DR) technology, incorporating 3D micro-CT imaging and numerical methods, has been widely employed to predict these properties. However, analyzing the pore structure of heterogeneous rocks, such as fractured rocks or glutenite, solely through single-scale DR analysis poses challenges. Existing upscaling methods have limitations in fully representing the complete range of pore structures at different scales, with limited comparison to experimental data. To address this, we propose a novel method that upscales porosity and simulates the MICP curve from nano-scale to core scale by merging results from micro-CT (at resolutions of 35 μm and 2 μm) and SEM (at resolutions of 6.5 nm and 65 nm). We validate the developed DR model by applying it to sandstones, glutenite, and igneous rocks, and achieve excellent agreement between the experimental data and the multi-scale DR model across 67 samples. The results demonstrate that the multi-scale model effectively captures the porosity and pore structures across the entire range. In contrast, the single digital rock (DR) model underestimates the porosity measurements for both homogeneous sandstones and heterogeneous cores. While the MICP model based on a single DR proves suitable for homogeneous rock samples, it introduces noticeable discrepancies when applied to heterogeneous rock samples. The developed multi-scale method significantly enhances the confidence in using DR to assess the pore structure of complex rocks.

Enhanced porous membrane fabrication using cellulose acetate and citric acid: Improved structural integrity, thermal stability, and gas permeability

In this study, our primary objective was to enhance the properties of porous membranes by addressing the limitations associated with phase separation. We employed a non-solvent induced phase separation (NIPS) method, utilizing cellulose acetate (CA) in conjunction with citric acid to fabricate these membranes. Citric acid played a dual role: ensuring a uniform pore structure and cross-linking the CA polymer, thereby enhancing its mechanical strength. This approach resulted in the development of a more robust membrane with superior structural integrity. Thermogravimetric analysis (TGA) confirmed enhanced thermal stability, particularly up to 150 °C, as a result of citric acid's cross-linking effect. Beyond 150 °C, the decomposition temperatures of the CA/citric acid membrane were found to be comparable to those of pure CA. Remarkably, a CA/citric acid ratio of 1:0.05 exhibited the slowest decomposition rate as the temperature increased. Scanning electron microscopy (SEM) examination unveiled a sponge-like membrane structure with numerous evenly distributed fine pores. Through the use of citric acid as a plasticizer, we were able to effectively control the penetration of water molecules, preventing the formation of macrovoids and promoting the creation of fine pores. This resulted in the fabrication of a high-porosity membrane, boasting an impressive porosity measurement of 84.9 %. Furthermore, measurements of the Gurley value confirmed efficient gas permeation, a critical characteristic for applications requiring effective gas transport. Fourier transform infrared (FT-IR) spectroscopy attested to the presence of citric acid in the membrane post-phase separation, indicating its successful integration. Our work presents a novel approach to enhance porous membranes, providing improvements in mechanical strength, thermal stability, and gas permeability. These findings offer valuable insights for the development of advanced materials with diverse applications in various fields.

Alternative Industrial Chrome-Free Alumina-Based Bricks for Copper Alloy Melting Furnaces

Abstract In this study, the corrosion resistance of alumina-based bricks against the slag of copper alloy melting furnaces was investigated. Four commercial chrome-free alumina bricks have been studied. Bulk density and apparent porosity measurements and phase analysis of the bricks were performed. The most important property, the slag corrosion resistance, was evaluated at the temperature of 1,200°C for 2 h. The microstructures of the bricks, their penetration depth, and corrosion index were evaluated. The results showed that two bricks showed acceptable corrosion resistance against the slag. The low corrosion index of these bricks was attributed to their aluminosilicate phases (sillimanite, or andalusite) and lower phosphate bonding; however, the problematic matter was the silicate phase, which showed lower resistance against the penetration of slag. It was observed that the aluminosilicate phase can improve the corrosion resistance through the reaction with slag, whereas the presence of large alumina aggregates can restrict the penetration of slag.

Effects of one-sided thermal shock and hold on alumina-based oxide/oxide ceramic matrix composites for temperatures in excess of 1200 °C

Nextel™720/alumina based ceramic matrix composite plates were subjected to one-sided thermal shock and 30-minute hold at 1100 °C, 1250 °C, 1400 °C and 1550 °C. Post exposure, the plates were evaluated for physical, structural, and microstructural changes using state-of-the art characterization techniques as well as standard mechanical testing procedures. Physically, no significant mass or dimensional changes were noted, while the surface roughness decreased on the exposed side for all the cases. Structurally, both the tensile and flexural strengths decreased for the 1550 °C case, but not for the other temperatures. In addition, short-beam strength tests showed no effect on interlaminar strength as a result of the elevated temperature exposures for the 30-minute duration considered. Microstructurally, SEM/EDS evaluations showed no significant change in the microstructure or element composition on the exposed and back sides. However, mercury intrusion porosity measurements did show a change in pore size distribution due to the combined effect of matrix shrinkage and further matrix microcracking. Combined results show that the operational limit of the composite can be pushed significantly beyond 1200 °C for shorter (in minutes) durations provided it is structurally viable for the application sought.

Photocatalytic degradation performance of antibiotics by WO3/α-Fe2O3/zeolite type II heterojunction with core-shell structure.

The accumulation of antibiotics in the environment can be harmful to human health, and research on their disposal technologies is of increasing interest. In this study, WO3/α-Fe2O3/zeolite (WFZ) type II heterojunction composites with core-shell structures were prepared by coupling WO3 semiconductors with visible-light photocatalytic activity with α-Fe2O3 via hydrothermal synthesis using zeolite as a carrier for the adsorption of synergistic photocatalytic degradation of antibiotics in wastewater. X-ray diffraction, X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), specific surface, and porosity measurements were used to characterize the structure of WFZ type II heterojunction. The performance of WFZ heterojunction for the visible photocatalytic degradation of antibiotics (tetracycline hydrochloride (TCH), ciprofloxacin (CIP), and levofloxacin hydrochloride (LVF)) was investigated. Through four photocatalytic cycles, the catalyst exhibited excellent durability and stability. This was attributed to the core-shell structure and type II heterojunction promoting the effective separation of photogenerated carriers and the extended visible light response range, which resulted in the best photocatalytic activity of the catalyst under visible light irradiation. Radical trapping experiments showed that superoxide radicals (•O2-) and hydroxyl radical (•OH) were the main active species that played a major role in the photocatalytic degradation. These findings show that the synthesized WFZ type-II heterojunction can be used as a reliable visible-light-responsive photocatalyst for the treatment of antibiotics in wastewater.

Effect of The Composition of TiO2 Additives on The Physical and Magnetic Properties Crystal Structure and Microstructure of BaFe12O19 Magnetic Ceramics

<p>In this research, the manufacture of barium hexaferrite (BaFe<sub>12</sub>O<sub>19</sub>) magnetic ceramics and the addition of titanium dioxide (TiO<sub>2</sub>) additives with variations of 0%: 0.3%: 0.6% and 0.9% used the powder metallurgical method. The characterization used in this study is the measurement of density, porosity, X-Ray Diffraction (XRD), Scanning Electron Microscope (SEM), Vibrating Sample Magnetometer (VSM), and Impulse Magnetizer K-Series. Based on the results of density and porosity measurements, the highest values were 4.95 g/cm3 and 5.45%, respectively. XRD results showed the formation of a BaFe<sub>12</sub>O<sub>19</sub> phase with some impurities at 0% (Fe<sub>2</sub>O<sub>3</sub>), 0.3% and 0.9% (Ti<sub>6</sub>O<sub>11</sub>), and 0.6% (Ti<sub>4</sub>O<sub>7</sub>). The SEM results showed that the morphology of TiO<sub>2</sub>-BaFe<sub>12</sub>O<sub>19</sub> was quite homogeneous, and the size and cavity ranged from 0.5 – 1.5 μm and 0.25 – 0.9 μm, respectively. VSM results show Mr, Ms, Hc, and Bhmax values of 1,489 kG, 3,235 kG, 1,758 kOe, and Bhmax of 0,867 MGOe, respectively. The results of the Impulse Magnetizer K-Series show the maximum and lowest magnetic flux values of 272.65 gauss and 218.10 gauss at 0.6% and 0% variation, respectively.</p>

Lithological and diagenetic variation of mixed depositional units in the middle permian saline lacustrine deposition, Junggar Basin, NW China

Mixed depositional reservoirs are widely distributed in Junggar Basin, NW China. These reservoirs are featured by complex lithology, ultra-low permeability and extremely heterogeneous pore structures that markedly impact field development efficiency. This study illustrated the distribution of lithological combinations within a single sand bar in the Middle Permian Lucaogou Formation, Jimsar Sag, Junggar Basin and revealed the diagenetic control on the reservoir quality of a single sand bar based on thin sections, scanning electron microscopy (SEM), helium porosity and air permeability measurement, pressure-controlled mercury injection (PMI), rate-controlled mercury injection (RMI), X-ray computed tomography (CT), and collected and published data. The results show that the heterogeneity of microscopic pore structures within a single sandbar is controlled by the distribution of various lithological combinations and different levels of diagenetic alteration. The results show that there are mainly three types of lithology developed in a single sand bar. The reservoir quality of dolomitic siltstone reservoirs is the best, followed by silty dolomite reservoirs. The reservoirs quality of dolomicrite reservoirs is the worst. Three main lithological combinations can be identified within a single sand bar. Controlled by climate, lake level fluctuation and provenance, lithological combination A, characterized by blended mixing of dolomitic siltstone, silty dolomite and dolomicrite, is mainly developed in the middle of single sand bar. Lithological combination B, characterized by saltatory mixing of interbedded dolomitic siltstone and dolomicrite, and lithological combination A developed on the side of the sand bar near the shallow lake, while lithological combination C with blended mixing of interbedded dolomitic siltstone and silty dolomite developed on the side near provenance. Strong compaction is the main factor of the decrease of reservoir quality of sand bar reservoirs. Carbonate cementation promotes the densification of reservoirs. The irregular flaky clay minerals lead to the exponential decline of permeability, and dissolution is the main kind of diagenesis to improve reservoir quality. The dolomitic siltstone reservoirs in the middle of a single sand bar have the best reservoir quality because the overlying dolomicrite layers resist compaction, resulted in a certain amount of primary pores remained. Besides, the dolomitic siltstone reservoirs are far from the sand-mudstone interfaces, which leads to the low carbonate cement content. Furthermore, abundant dissolution pores in dolomitic siltstone reservoirs improve the reservoir quality. These research results are crucial to reservoir evaluation and development in similar mixed depositional tight reservoirs.

Unlocking Continental Shale Oil Potential: Microscopic Insights into Fluid Saturation Mechanisms via Imbibition for Future Development Strategies in the Songliao Basin

Summary Microscopic assessment of oil distribution and imbibition mechanisms within shale formations lays the groundwork for future development strategies. In this regard, the Songliao Basin’s continental shale oil holds immense exploration and development potential. In this study, we focus on shale samples extracted from the first member of the Qingshankou Formation (Q1) within the Songliao Basin. These samples were subjected to a comprehensive analysis, encompassing mercury injection capillary pressure (MICP), porosity, and permeability measurements and detailed monitoring processes. The experimental protocol involved multiple injection cycles, commencing with spontaneous oil imbibition, followed by a series of differential pressurized oil saturation stages (eight pressurization steps ranging from 0.2 MPa to 10 MPa). Subsequently, forced imbibition using slickwater under varying pressures was used, and the process was meticulously monitored via gravimetric and nuclear magnetic resonance (NMR) measurements to deduce relative fractions within distinct pores across the entire experimental process. Notably, the results unveiled that, during oil saturation through spontaneous imbibition, the interbedd-type shale core samples exhibit more efficient oil saturation compared with the organic-rich dark massive type. In the former, clay interlayers predominate in absorbing oil, while the latter showcases preferential saturation of mesopores and macropores. Following the differential pressurized oil saturation phase, clay interlayers continued to play a significant role in both sample types, accounting for 54.2% and 57.0% of the interbed-type and massive shale’s oil intake, respectively. Furthermore, a quantification of the slickwater imbibition recovery originating from pores of varying sizes under distinct pressures revealed that clay interlayers and micropores are the primary contributors to imbibition recovery in both sample types. Collectively, the experimental findings corroborate that shale oil can be displaced from nanopores to larger matrix pores and bedding fractures through imbibition, offering valuable insights for enhancing oil recovery operations in practical field scenarios.

Synthesis and characterisation of hybrids composed of calcined hydrotalcite and residual textile dyes

There is growing concern about the health of our planet, which has led to a search for methods to purify and recover the pollutant materials that are released into the environment. Among all industries, the dyeing sector of the textile industry is considered one of the most polluting. However, advancements in technology, such as the use of nanoadsorbents, have made it possible to effectively treat and clean these wastewaters by harnessing the adsorption capabilities of these minerals. As a result, highly functional pigmentary hybrids with improved characteristics can be obtained. In this study, the research focuses on exploring the potential of hydrotalcite in combination with reactive, disperse, and direct dyes. Colour measurements are conducted using reflection spectrophotometers to evaluate the colour performance of the hybrid materials, yielding successful results. X-ray diffraction (XRD) analysis is used to verify the structural integrity of the hydrotalcite and confirm the adsorption of the dyes. Additionally, thermogravimetric tests (TGA) are carried out to assess the thermal stability of the different samples, while the colorants’ protection provided by the hydrotalcite is evaluated through total soluble recovery (TSR) measurements. An FTIR analysis is used to detect the presence of characteristic functional groups of the dyes in the resulting hybrids. Surface area and porosity measurements utilising the BET method, along with Scanning Electron Microscopy Energy+Dispersive X-ray spectroscopy (SEM–EDX) and X-ray photoelectron spectroscopy (XPS) tests, are also conducted. In summary, this study investigates the potential of hydrotalcite as an effective adsorbent for various dyes used in the textile industry. The research involves comprehensive analyses, including colour evaluation, structural characterisation, thermal stability assessment, and surface morphology examination. These findings contribute to the development of sustainable and environmentally friendly approaches in the treatment of textile wastewater.

The porosity of felsic pyroclasts: laboratory validation of field-based approaches

Volcanic eruptions are driven by magma rising through Earth’s crust. The style of an eruption depends on intrinsic and extrinsic parameters and is commonly a dynamic process. Thorough and holistic investigation of the related products is key to understanding eruptive phenomena and assessment of volcano-specific hazards. Models of such phenomena are constrained by quantification of the dispersal, the grain size distribution, and pyroclast textures. Pyroclast texture may be described in part by measurements of density and porosity, which depend on pyroclast volume determination. Yet volume determination of irregularly shaped pyroclasts cannot be achieved with geometrical laws, instead necessitating the use of alternative methodologies. Here, we test three methodologies to quantify pyroclast volume on a set of clasts collected from the Minoan eruption deposits from Santorini, Greece. We compare (1) a manual method for obtaining the lengths of three orthogonal axes of the pyroclast with a caliper, (2) an optical method to measure the longest and shortest axes of the pyroclast via multiple photographs, and (3) an Archimedean buoyancy-based method. While the optical and manual methods provide almost identical values of pyroclast volume when tested under laboratory conditions, there is a discrepancy between these two methods and the Archimedean method, which produces an overestimation of ca. 13% in volume. This discrepancy has little impact on the subsequent assessment of porosity and density for which the natural variability of values is observed to be broader. We therefore propose using the manual approach in the field as a simple and fast, yet reliable, method to obtain large volumes of quantitative data on the texture of erupted products, and we also provide a correction factor for in-field volume assessment of rhyodacitic pumices.