Large Pore Research Articles

Deconvoluting the Effect of Cell-Penetrating Peptides for Enhanced and Controlled Insertion of Large-Scale DNA Nanopores.

DNA nanopores have emerged as powerful tools for molecular sensing, but the efficient insertion of large DNA nanopores into lipid membranes remains challenging. In this study, we investigate the potential of cell-penetrating peptides (CPPs), specifically SynB1 and GALA, to enhance the insertion efficiency of large DNA nanopores. We constructed SynB1- or GALA-functionalized DNA nanopores with an 11 nm inner diameter and visualized and quantified their membrane insertion using a TIRF microscopy-based single-liposome assay. The results demonstrated that incorporating an increasing number of SynB1 or GALA peptides into the DNA nanopore significantly enhanced the membrane perforation. Kinetic analysis revealed that the DNA nanopore scaffold played a role in prearranging the CPPs, which facilitated membrane interaction and pore formation. Notably, the use of pH-responsive GALA peptides allowed highly efficient and pH-controlled insertion of large DNA pores. Furthermore, single-channel recording elucidated that the insertion process of single GALA-modified nanopores into planar lipid bilayers was dynamic, likely forming transient large toroidal pores. Overall, our study highlights the potential of CPPs as insertion enhancers for DNA nanopores, which opens avenues for improved molecule sensing and the controlled release of cargo molecules.

Coupling control of organic and inorganic rock components on porosity and pore structure of lacustrine shale with medium maturity: A case study of the Qingshankou Formation in the southern Songliao Basin

Shale components affect organic–inorganic diagenesis, control the formation and evolution of pore structure, and lead to heterogeneity of shale reservoirs. Therefore, revealing the coupling control of shale components on the porosity and pore structure is crucial for selecting the dominant lithofacies. In this study, the lacustrine shale with medium maturity in the first member of the Qingshankou Formation (Qing1 Member) in the Changling Sag, southern Songliao Basin, China, was analyzed. Using pressurized sealed original shale samples and 2-D nuclear magnetic resonance (2D-NMR) analysis, the effective porosity of shale was accurately determined. The pore structure was characterized via experiments such as low-temperature nitrogen adsorption, NMR, and scanning electron microscope (SEM) analyses. In addition, the joint influences of the shale rock components, sedimentary structure, and maturity on the porosity and pore structure were investigated. Finally, the favorable reservoirs in the lacustrine shale with medium maturity and their formation conditions were identified. Studies have shown that for lacustrine shale with medium maturity: (1) a moderate total organic carbon (TOC) content (between 1% and 2.5%) is a key factor for improving the effective porosity and the proportions of mesopores (100–1000 nm) and small-pores (30–100 nm). This is related to the generation of organic acids and the cracking of organic matter into pores. An excessive TOC content can lead to increased plasticity of the rock and filling of the pores by bitumen. (2) The porosity and pore structure are controlled by the organic matter and inorganic minerals as well as sedimentary structure. Organic matter has dual impacts on the porosity improvement related to clay minerals, promotion of clay conversion and filling of clay-related pores, and the ratio of the clay content to the TOC (Vsh/TOC) can reflect the degree of influence of organic matter, the greater the Vsh/TOC ratio is, the greater the effective porosity and proportion of micropores are. (3) Organic matter and felsic minerals jointly effect the improvement of the effective porosity and larger pores (>30 nm), which is related to their good compression resistance, organic pore retention, and dissolution-enhanced porosity effect. The product of the TOC and felsic mineral content (Vsi*TOC) can reflect the degree of their coupled effect. For moderate TOC contents, a higher felsic mineral content, and moderate shell laminae (Vca>10%) are conducive to the development of the effective porosity and larger pores. (4) The organic medium-rich argillaceous laminated felsic shale and organic-medium argillaceous laminated clayey shale have a higher effective porosity and higher proportion of larger pores, making them the dominant lithofacies for shale oil sweet spots.

Sustainable mechanochemical synthesis of catalytically graphitized mesoporous carbons

So far it is difficult to achieve both a high graphitization degree and uniform mesopores in carbons, especially via a sustainable synthesis approach. This work shows that mesoporous graphitized carbons predominantly composed of amorphous and/or partially graphitic carbon nanotubes can be obtained by a simple mechanochemical synthesis using tannins as carbon precursors, iron salt as a graphitization catalyst and block copolymer as a soft template. The one-pot synthesis relied on the fast ball milling of a Pluronic-type template, tannins, and iron salt, followed by the direct thermal treatment at a certain temperature (e.g., 750 °C) leading to mesoporous carbons with a high degree of graphitization (up to 75%), high specific surface areas up to 360 m2/g, and large mesopore volumes up to 0.40 cm3/g. Moreover, the procedure can be extended for the synthesis of highly porous activated carbons with uniform mesoporosity by adding potassium oxalate to the milling system. The procedure afforded activated mesoporous carbons with substantially uniform mesopores of about 7.7 nm, a high specific surface area of 1100 m2/g, a large pore volume of 0.84 cm3/g, and enhanced CO2 adsorption capacity up to 4.0 mmol/g at ambient conditions. This synthetic approach offers advantages in terms of scalability, simplicity, and reduced environmental impact in comparison to traditional synthesis methods.

Preparation of high-flux polyethylene hollow fiber microfiltration membranes with multiple pore structure through the combination technology of braided tube reinforcement and TIPS method

Our team proposed the continuous preparation of the reinforced polyethylene (PE) hollow fiber microfiltration (MF) membranes based on the combination technology of braided tube reinforcement and thermally induced phase separation (TIPS) method. In this work, to improve the permeability and reduce the flux attenuation, we selected PE as the membrane-forming polymer, polyethylene glycol (PEG) and sodium chloride (NaCl) as the composite pore-forming agents to optimize the membrane-forming composition. In particular, the effect of NaCl contents on the permeation of the reinforced PE hollow fiber membranes was studied in detail. The reinforced PE hollow fiber MF membranes obtained the multiple pore structure containing small pores, large pores and cavity structure. The small pores were formed by PEG and white oil. The large pores and the cavity structure were formed by the discreted and agglomerated NaCl, respectively. The cavity structure provided the connectivity gaps for the small pores and forming an internal highly connected pathways, which could reduce the transmembrane resistance. Thus, the flux improved obviously with the increasing NaCl contents. When the NaCl content was 30 wt%, the pure water flux of the reinforced PE hollow fiber MF membranes could reach 1606.0 L·m−2 h−1 after pre-pressuring for 30 min. In addition, the reinforced PE hollow fiber MF membranes exhibited excellent tensile strength with 170.0 MPa and good corrosion resistance, which showed a great application potential in harsh environments. In particular, this method provides a new idea for the continuous preparation of the reinforced PE hollow fiber MF membranes.

In-situ automated fiber placement gap defects filled by fused granular fabrication

This paper presents an investigation into the effect of Fused Granular Fabrication gap filling on the composition and mechanical performance of in-situ consolidation Automated Fiber Placement-manufactured laminates. Two laminates with staggered triangular gap defects were manufactured using in-situ consolidation Automated Fiber Placement. In the first laminate, the defects remained unmodified whereas in the second laminate Fused Granular Fabrication was used to fill the gap defects to mitigate out-of-plane waviness in subsequent plies and large pores which can initiate cracks. The process was successfully demonstrated. Fused Granular Fabrication layer thickness was however hard to adjust to match consolidated ply thickness of the AFP process due to the slightly uneven surface of the AFP substrate resulting in out-of-plane undulations. Compressive strength remained at the same level for both, reference and gap specimens. Tensile strength decreased 11 % and 23 % for gap defects and filled gap defects, respectively. Further work is required to utilize the full potential of the process combination.

Refined Pore Structure Design and Surface Modification of 3D Porous Copper Achieving Highly Stable Dendrite‐Free Lithium‐Metal Anode

Abstract3D porous copper is anticipated to serve as an ideal current collector for lithium‐metal anodes (LMAs) owing to its excellent conductivity, huge surface area, and cost‐effectiveness. However, most pertinent studies center around commercial copper foams, where their notable large pore size (150–400 µm) is identified as a primary inducement for dendrite formation and ultimate battery failure. Hence, ensuring the appropriate pore structure in 3D porous copper for achieving highly reversible lithium deposition/stripping process plays a pivotal role in stabilizing LMAs. Herein, the hydrogen bubble template method is employed to fabricate five distinct types of 3D porous copper. Among them, the one with an average surface pore diameter of 25.18 µm and the lowest probability of macropores distribution within the pore walls demonstrates optimal electrochemical performance. To further improve the inherent lithiophobicity of copper, Cu2Se/Cu2O heterostructure nanowires are loaded as kinetic enhanced nucleation sites. Benefiting from the synergistic effect of optimized pore structure and heterostructure nanowires, the Cu2Se/Cu2O@3D Cu composite current collector exhibits excellent dendrite‐free characteristics and outstanding electrochemical performance, showcasing an ultra‐long symmetrical‐cell lifespan of 3000 h at 1 mA cm−2 and stability for 300 h even under 20 mA cm−2.

Investigation on the influence of gradation design on the road performance of cold mixed epoxy asphalt mixture based on microstructure evaluation

Cold mixed epoxy asphalt mixture (CMEAM) has excellent anti-deformation and fatigue performance which shows remarkable superiority on bridge pavements. Previous studies have done comprehensive researches on its properties through macroscopic experiments. However, few studies revealed the impact of gradation design on the road property of CMEAM through microscopic method. Thus, in this paper, X-Ray computed tomography (X-ray CT), nanoindentation (NI), field emission scanning electron microscopy (FESEM) and mercury intrusion porosimetry (MIP) are introduced to investigate the coarse aggregates contact degree, the thickness and elastic modulus of interfacial transition zone (ITZ) and the pore diameter distribution of CMEAM. Results showed that the contact points of coarse aggregates in EA-05 mixture are around 40 while those in EA-10 mixture are around 20. (40°, 50°) is the key inclination angle interval for EA-10 mixture type while (70°, 80°) and (10°, 20°) are of significance for EA-05 mixture type. The contact points and inclination angles are positively and inversely proportional to Marshall stability, respectively. In addition, the ITZ thickness of EA-05 and EA-10 mixture is below 10 μm and above 40 μm, respectively. The ITZ elastic modulus of EA-10 mixture is approximately 1.5 times than that of EA-05. The thickness and elastic modulus of ITZ are inversely proportional to low-temperature indirect tensile strain (εT). Meanwhile, EA-05 mixture has higher proportion in gel micropores and middle capillary pores while EA-10 mixture has higher proportion in mesopores and large capillary pores. Mesopores has the highest correlation coefficients with tensile strength ratio (TSR), followed by large capillary pores. The suggested proportion for above two type pores is around 21.5% and 51.0%, respectively.

Pore-Scale Modeling of Pressure-Driven Flow and Spontaneous Imbibition in Fracturing-Shut-In-Flowback Process of Tight Oil Reservoirs

Tight oil reservoirs are characterized by multiple pore spaces where nano-micropores and multiscale fractures coexist, and each type of medium varies in scale, implying a tight coupling of multiscale fractures with matrix and giving rise to extremely complicated flow patterns. To further investigate its flow mechanism, we first construct three two-dimensional (2-D) fracture-pore geometry models based on microfocus computed tomography (CT) imaging of a typical tight rock. A pore-scale modeling workflow is thereafter developed using the Shan-Chen lattice Boltzmann model (SC-LBM) to simulate the pressure-driven flow and spontaneous imbibition. The influence of fracture-pore geometry on the pore-scale fluid exchange dynamics in the fracturing-shut-in-flowback process is clearly clarified. Results show that, for the porous medium model without fracture, the fracturing fluid can displace and replace some crude oil by spontaneous imbibition while a large amount of crude oil droplets remains unexploited away from the oil/water contact line, resulting in a low oil imbibition recovery. The injected fracturing fluid migrates into the deep position along the fractures, only a few entering the matrix pore space near the fractures. Small pores are the main channel for fracturing fluid to imbibe into the matrix pores, and the replaced crude oil droplets flow into fractures through large pores as intermittent or continuous pipe flow. The complexity of fracture network typically exerts a significant impact on the fluid exchange dynamics during pressure-driven flow and spontaneous imbibition. The more complex the fracture network, the larger the volume of fracturing fluid injected, the easier for oil droplets replaced from the matrix pores, and the more difficult for the flowback of fracturing fluid in the fracture-pore geometry model. Our understanding will provide a basis for explaining the underlying mechanisms of oil replacement by pressure-driven flow and spontaneous imbibition in the fracturing-shut-in-flowback process.

Research on water blocking and residue damage mechanism of fracturing fluid in Yongjin tight reservoirs

The existing reservoir in the Yongjin block exhibits an extremely low matrix permeability, posing challenges in precisely evaluating the damage caused by fracturing fluid using traditional core flow experimental methods. Currently, there is no established quantitative method for characterizing the degree of damage. In this study, we integrated online nuclear magnetic resonance, microscopic computed tomography, and core displacement experimental techniques, pioneering a novel approach to evaluate damage in deep tight oil reservoirs subjected to hydraulic fracturing. We analyzed the influence patterns of key factors such as backflow pressure differential, shut-in time, invasion volume, and residual retention on rock matrix damage in the operational area. The study unveiled the mechanisms behind water sensitivity, water block, and fracturing fluid retention damage among oil, water, and rock. The results indicate that water sensitivity damage is less than 20%, primarily occurring within large pores. Water block damage can significantly reduce the residual oil permeability. Experimental findings suggest that optimizing liquid backflow with a pressure differential and well shut-in time set at 5 MPa and 9 days can markedly reduce the intrusion volume of gel-breaking fluid, restoring the residual oil permeability. Under high-pressure differential conditions, residual fracturing fluid can infiltrate the rock matrix, resulting in pore damage. Additionally, it can accumulate on the fracture surfaces, thereby reducing the permeability of microfractures.

Hydraulic conductivity over a wide suction range of loess with different dry densities

Experimental research into the hydraulic conductivity curve (HCC) of unsaturated soil is limited due to the inherent challenge associated with labor, cost, and time. Typically, the HCC is estimated using the soil water characteristic curve (SWCC) based models and saturated hydraulic conductivity (SHC). However, the efficiency of the SWCC-based model is rarely assessed, and the influence of soil density and pore structure on HCC remains incomplete due to limited experimental data. To address this gap, this study employs an innovative filter-paper-based column method, which can measure the HCC over a wide suction range (e.g. 0−105 kPa), to capture the HCCs of both intact and compacted specimens with varying dry densities. The efficiency of two typical SWCC-based models is assessed using the measured data. Meanwhile, the mercury intrusion porosity (MIP) technique is employed to obtain the pore characteristic (i.e. pore size distribution (PSD)) and a method of predicting the HCC using the PSD data is proposed, emphasizing the dominant role of the pore structure in shaping the HCC. The results reveal that the dry density's influence on the HCC is primarily observed within the low suction range, corresponding to variations in the dominant and large pores. In the high suction range, the HCCs align along a linear trajectory when plotted in a log-log format. A notable finding is the overestimation of the HCC obtained from the SWCC-based models using the measured SHC. When the SHC is regarded as a fitting parameter, good agreement is achieved. The adjusted SHC value is typically 0-1 order of magnitude lower than the measured value, and this discrepancy diminishes as dry density increases. On the other hand, the proposed PSD-based model performs well with the measured SHC data. Caution is exercised when using the SHC to estimate the HCC for modeling water movement in partially saturated soil.

Fine quantitative characterization of high-H2S gas reservoirs under the influence of liquid sulfur deposition and adsorption

In order to clarify the influence of liquid sulfur deposition and adsorption to high-H2S gas reservoirs, three types of natural cores with typical carbonate pore structures were selected for high-temperature and high-pressure core displacement experiments. Fine quantitative characterization of the cores in three steady states (original, after sulfur injection, and after gas flooding) was carried out using the nuclear magnetic resonance (NMR) transverse relaxation time spectrum and imaging, X-ray computer tomography (CT) of full-diameter cores, basic physical property testing, and field emission scanning electron microscopy imaging. The loss of pore volume caused by sulfur deposition and adsorption mainly comes from the medium and large pores with sizes bigger than 1 000 μm. Liquid sulfur has a stronger adsorption and deposition ability in smaller pore spaces, and causes greater damage to reservoirs with poor original pore structures. The pore structure of the three types of carbonate reservoirs shows multiple fractal characteristics. The worse the pore structure, the greater the change of internal pore distribution caused by liquid sulfur deposition and adsorption, and the stronger the heterogeneity. Liquid sulfur deposition and adsorption change the pore size distribution, pore connectivity, and heterogeneity of the rock, which further changes the physical properties of the reservoir. After sulfur injection and gas flooding, the permeability of Type I reservoirs with good physical properties decreased by 16%, and that of Types II and III reservoirs with poor physical properties decreased by 90% or more, suggesting an extremely high damage. This indicates that the worse the initial physical properties, the greater the damage of liquid sulfur deposition and adsorption. Liquid sulfur is adsorbed and deposited in different types of pore space in the forms of flocculence, cobweb, or retinitis, causing different changes in the pore structure and physical property of the reservoir.

Development of Mn doped ZnAl2O4 via hydrothermal method as photocatalyst for Cr(VI) reduction under visible light

A hydrothermal method was employed to synthesise zinc aluminate oxides doped with manganese, with the aim of enhancing the photocatalytic reduction of hexavalent chromium to trivalent chromium. The optical, textural, microscopic, and structural features of the materials were assessed by a range of analytical techniques. These results revealed that incorporation of Mn dopant into the ZnAl2O4 (ZAO) reduced to band gap of ZAO and MD-ZAO are 3.56 and 2.79 eV, respectively. The best photoreduction efficiency was found with manganese-doped ZnAl2O4 (MD-ZAO) is 86.39 % than ZAO (69.38 %) after 120 min. The surface area study displays the 21.43 and 38.65 m2 g−1 for ZAO and MD-ZAO, respectively. When surface area of a nanomaterial is increased, a greater percentage of the material in contact with Cr ion, which increases the photocatalytic activity. A large interfacial area and pore volume aids in development of photoinduced electrons (e−) as well as hole pairs. The impedance study indicates the lower Rct value of ZAO and MD-ZAO are 0.45 Ω and 0.7 Ω, respectively. The finding indicates that Mn doped ZnAl2O4 work as excellent photocatalyst for photoreduction of hexavalent of Cr. The doped material can also act as potential catalyst in different future electrochemical and photocatalytic study.

Experimental testing and mechanism investigation of amine-functionalized layered vermiculite for CO2 capture

Solid amine adsorbents have attracted significant attention due to their low energy consumption, high selectivity, and environmental friendliness, positioning them as the most promising technology for CO2 capture. However, current adsorbent carrier materials commonly encounter challenges such as expensive costs and inadequate stability. In this study, acid-activated expanded vermiculite carrier (AEV) with a large pore volume and hierarchical pore structure was prepared. Subsequently, a series of functionalized polyethyleneimine (PEI) adsorbents were synthesized and employed in CO2 capture experiments to investigate the impact of PEI loading and temperature on adsorption characteristics. The results showed that the acid-modified expanded vermiculite with a large pore volume structure significantly increased amine loading, while the layered structure network promoted amine dispersion. Under the conditions of 50 wt% PEI loading, the CO2 capture capacity of AEV reached 3.29 mmol/L at 75 ℃. Furthermore, density functional theory was utilized to calculate the adsorption energy and Gibbs free energy change of CO2 and polyethyleneimine molecules. The HOMO and LUMO distributions of CO2 molecules with different polyethyleneimine chains were determined using frontier orbital theory, combined with infrared spectroscopy results confirming the conversion of CO2 into carbamate. Additionally, AEV-PEI50 adsorbent exhibited good stability during 8 cycles of the adsorption process. The obtained results demonstrate that the utilization of layered mesoporous scaffolds offers notable benefits in terms of efficient CO2 capture.

Effect of Na3AlF6 contents in refining flux on 3D characteristics of pore and mechanical properties of recycled Al-Mg-Si alloy

Fluoride is an essential and effective component in solid refining flux due to its ability to dissolve Al2O3. In this paper, the effects of Na3AlF6 content in refining flux on the pores and mechanical properties of recycled Al-Mg-Si alloy was investigated by tensile testing, scanning electron microscope (SEM) and Synchrotron radiation X-ray computed tomography (SRXCT). The results show that addition of Na3AlF6 transformed the shrinkage pores with large-sized irregular-shaped to highly spherical hydrogen pores, resulting in a significant reduction in pore volume fraction. When the refining flux with 5% Na3AlF6 is added to the melt, the volume fraction and average equivalent diameter of pores in the recycled alloy decreased by 84% and 23.2%, respectively, compared to those flux of without Na3AlF6. Furthermore, adding Na3AlF6 improves pore distribution uniformity while reducing the equivalent diameter of the largest pore by 83.7%. Although increasing Na3AlF6 content slightly increases pore equivalent diameter, it significantly reduces both larger pores (Equivalent diameter ≥20 μm) and their proportion. Moreover, the elongation of recycled Al gradually increases with higher Na3AlF6 content and reaches up to 21%, which is 40% higher than that without Na3AlF6. This improvement can be attributed primarily to reduced size and sphericity of shrinkage pores.

Synergistic effect of surfactant and silica nanoflowers support on CO2 capture from simulated flue gas by solid amine adsorbents

Solid amine adsorbents were synthesized by functionalizing silica nanoflowers (MSN) with large pore volume using Pluronic P123 (P123) and Polyethyleneimine (PEI) to explore their synergistic effect of CO2 capture. At the optimal loading of 65 wt% PEI and 5 wt% P123, the adsorbent (65PEI/5P123-MSN) displayed peak adsorption performance of 4.12 mmol/g under the dry condition. Notably, the introduction of 3 vol% moisture further increased the adsorption capacity of 65PEI/5P123-MSN to 5.33 mmol/g. Meanwhile, the Avrami kinetic model and the thermodynamic analysis shows that adding P123 reduces adsorption heat (55.89 kJ/mol) and regeneration energy (2.01 GJ/ton) of the adsorbent.

Biogas upgrading and membrane anti-fouling mechanisms in electrochemical anaerobic membrane bioreactor (EC-AnMBR): Focusing on spatio-temporal distribution of metabolic functionality of microorganisms

Electrochemical anaerobic membrane bioreactor (EC-AnMBR) by integrating a composite anodic membrane (CAM), represents an effective method for promoting methanogenic performance and mitigating membrane fouling. However, the development and formation of electroactive biofilm on CAM, and the spatio-temporal distribution of key functional microorganisms, especially the degradation mechanism of organic pollutants in metabolic pathways were not well documented. In this work, two AnMBR systems (EC-AnMBR and traditional AnMBR) were constructed and operated to identify the role of CAM in metabolic pathway on biogas upgrading and mitigation of membrane fouling. The methane yield of EC-AnMBR at HRT of 20 days was 217.1 ± 25.6 mL-CH4/g COD, about 32.1 % higher compared to the traditional AnMBR. The 16S rRNA analysis revealed that the EC-AnMBR significantly promoted the growth of hydrolysis bacteria (Lactobacillus and SJA-15) and methanogenic archaea (Methanosaeta and Methanobacterium). Metagenomic analysis revealed that the EC-AnMBR promotes the upregulation of functional genes involved in carbohydrate metabolism (gap and kor) and methane metabolism (mtr, mcr, and hdr), improving the degradation of soluble microbial products (SMPs)/extracellular polymeric substances (EPS) on the CAM and enhancing the methanogens activity on the cathode. Moreover, CAM biofilm exhibits heterogeneity in the degradation of organic pollutants along its vertical depth. The bacteria with high hydrolyzing ability accumulated in the upper part, driving the feedstock degradation for higher starch, sucrose and galactose metabolism. A three-dimensional mesh-like cake structure with larger pores was formed as a biofilter in the middle and lower part of CAM, where the electroactive Geobacter sulfurreducens had high capabilities to directly store and transfer electrons for the degradation of organic pollutants. This outcome will further contribute to the comprehension of the metabolic mechanisms of CAM module on membrane fouling control and organic solid waste treatment and disposal.

Molecular insights into the carbon dioxide sequestration in kerogen: An accelerated algorithm coupling molecular dynamics simulations and Monte Carlo methods

Carbon capture and storage (CCS) technology has been applied successfully in recent decades to reduce carbon emissions and alleviate global warming. In this regard, shale reservoirs present tremendous potential for carbon dioxide (CO2) sequestration as they have a large number of nanopores. An accelerated algorithm coupling molecular dynamics (MD) and Monte Carlo (MC) methods (MDMC) were employed in this work to study the sequestration behavior of CO2 in shale organic porous media. The MDMC method is used to analyze the spatial states of CO2, and the results are in good agreement with MD’s results, and MDMC is thousands of times faster compared to the classical MD. With regard to the kerogen matrix, its properties, such as the pore size distribution (PSD), pore volume, and surface area, are determined to describe its different compression states and the effects of CO2 absorption on it. The potential energy distribution and potential of mean force are analyzed to verify the spatial distribution of CO2 molecules. The heterogeneity of the pore structure resulted in heterogeneous distributions of CO2 molecules in kerogen porous media. Moreover, strong compression of the matrix reduces the number of large pores, and the PSD is mainly between 0 and 15 Å. Despite the high interaction force of the kerogen matrix, the high-potential-energy region induced by the kerogen skeleton also contributes to the formation of low-energy regions that encourage the entry of CO2. An increase in temperature facilitates the absorption process, allowing CO2 molecules to enter the isolated pores with stronger thermal motion.

Analysis of the Distribution Pattern of Remaining Oil and Development Potential after Weak Gel Flooding in the Offshore LD Oilfield.

The LD oilfield is one of the representative offshore oilfields. After weak gel flooding, the recovery rate is significantly improved. However, the oilfield is then in a medium- to high-water content stage, presenting a complex distribution of the remaining oil. The measures for further enhanced oil recovery (EOR) are uncertain. As a result, it is necessary to clarify the distribution pattern and development potential of the remaining oil during the high-water content period after weak gel flooding. In this study, an online nuclear magnetic resonance (NMR) oil displacement experiment and microscopic oil displacement experiment were conducted, and the mechanisms of weak gel flooding and the distribution pattern of the remaining oil were clarified in the LD oilfield. Additionally, high-multiple water flooding and numerical simulation experiments were conducted to analyze the development potential after weak gel flooding. The results show that the effect of weak gel flooding was more significant in the core of 1500 mD, with an increase in oil recovery of 9% compared to 500 mD. At a permeability of 500 mD, the degree of crude oil mobilization in micropores and small pores caused by weak gel flooding was improved by 29.64% and 23.48%, respectively, compared with water flooding. At 1500 mD, the degree of crude oil mobilization in small pores caused by weak gel flooding was increased by 37.79% compared to water flooding. After weak gel flooding, the remaining oil was primarily distributed in medium and large pores. Microscopically, the remaining oil was dominated by cluster residual oil, accounting for 16.49%, followed by columnar, membranous, and blind-end residual oil. High multiple water flooding experiments demonstrated that weak gel flooding could significantly reduce development time. The ultimate oil recovery efficiency of 500 mD and 1500 mD reached 71.85% and 80.69%, respectively. Numerical simulation results show that the ultimate oil recovery efficiency increased from 62.04% to 71.3% after weak gel flooding. This indicated that the LD oilfield still had certain development potential after weak gel flooding. The subsequent direction for enhanced oil recovery focuses mainly on mobilizing oil in medium pores or clustered remaining oil. This will play a crucial role in further exploring methods for utilizing the remaining oil and increasing the recovery rate.

Implications of the depositional and diagenetic attributes on the reservoir properties of the siliciclastic mangahewa formation, Taranaki Basin, New Zealand: Integrated petrographical and petrophysical studies

The siliciclastic Mangahewa reservoir in the Pohokura Gas Field presents a formidable challenge for gas exploration due to its diverse petrophysical properties. To address this challenge, our study employs a comprehensive approach integrating petrography and petrophysical analyses for core and well logging data. In the present study, we uncover an association of sandstone microfacies, in the key wells like Pohokura South-1, Pohokura-1, and Pohokura-2 wells, which change from fine to medium-grained subfeldsarenites to lithic feldsarenites microfacies. The petrographic investigation pinpoints the critical factors influencing the reservoir quality, including facies types, grain size, pore types, sedimentary structure, detrital clay content, and mineral composition. Both the primary intergranular and secondary dissolution pore spaces are responsible for the influential large intergranular pore volumes causing a superior reservoir quality. Mineral composition, influenced by the source and lithofacies, significantly impacts the reservoir properties. Diagenetic processes further control the reservoir quality, where the abundant silica cement, the illitic clays, and the rare pervasive carbonate cementation render the low reservoir quality. Compaction significantly reduces porosity during diagenesis. High-quality reservoir sandstones are characterized by coarse grain size, minimal detrital clay presence, predominantly quartz composition, limited carbonate and moderate silica cementation, low authigenic illite levels, and minor compaction impact. Based on the petrophysical data, the Mangahewa reservoir is composed of five RRTs (reservoir rock types) with the RRT1 samples having the best reservoir characteristics due to their fair porosity, very good permeability, and macro pore sizes. On the other side, the RRT5 samples are characterized by the lowest reservoir quality (poor porosity and permeability and micropore sizes) due to cementation and compaction. Our study provides valuable insights into the intricate petrophysical properties of the Mangahewa reservoir, enhancing the predictability of the reservoir behavior and optimizing hydrocarbon production in this challenging geological setting.

Integrative taxonomy supports two new species of Macrobiotus (Tardigrada: Eutardigrada: Macrobiotidae) allowing further discussion on the genus phylogeny

In this study, I describe two new species of Macrobiotus based on morphological data collected through light and scanning electron microscopy. Both species are accompanied by DNA sequences from four commonly used molecular markers (18S rDNA, 28S rDNA, ITS-2, and COI). Macrobiotus ovovittatus sp. nov. was discovered in Greenland and can be distinguished from similar taxa of Macrobiotus by its continuous, solid, and clearly wrinkled egg surface, adorned with sparse, very small and irregularly spaced pores. Additionally, the terminal discs of egg processes are covered in multiple light-refracting dots, resembling crocheted napkins. Macrobiotus mileri sp. nov. was found in Israel and is characterized by unique pore arrangements in its body cuticle, expressed in two distinct animal forms: (i) forma porata with large pores arranged in five distinct patches and (ii) forma aporata with single, almost undetectable pores. It also features weakly defined convex terminal discs with smooth edges. Furthermore, the phylogenetic analyses conducted in this study offer the most updated phylogeny of superclade I within the family Macrobiotidae. This facilitates additional discussion concerning the interrelationships among species within the genus Macrobiotus and the circumscription of species groups within it.