Sediment Properties Research Articles

Occurrence, Distribution, and Trophic Transfer of Pharmaceuticals and Personal Care Products in the Bohai Sea.

The ubiquitous presence of pharmaceuticals and personal care products (PPCPs) in environments has aroused global concerns; however, minimal information is available regarding their multimedia distribution, bioaccumulation, and trophic transfer in marine environments. Herein, we analyzed 77 representative PPCPs in samples of surface and bottom seawater, surface sediments, and benthic biota from the Bohai Sea. PPCPs were pervasively detected in seawater, sediments, and benthic biota, with antioxidants being the most abundant PPCPs. PPCP concentrations positively correlated between the surface and bottom water with a decreasing trend from the coast to the central oceans. Higher PPCP concentrations in sediment were found in the Yellow River estuary, and the variations in the physicochemical properties of PPCPs and sediment produced a different distribution pattern of PPCPs in sediment from seawater. The log Dow, but not log Kow, showed a linear and positive relationship with bioaccumulation and trophic magnification factors and a parabolic relationship with biota-sediment accumulation factors. The trophodynamics of miconazole and acetophenone are reported for the first time. This study provides novel insights into the multimedia distribution and biomagnification potential of PPCPs and suggests that log Dow is a better indicator of their bioaccumulation and trophic magnification.

An Analytical Model and Its Application in Reliability Analysis of Formation Failure during Hydrate Production in Deep-sea Areas

Methane hydrates (MHs) have potential economic and environmental significance. However, due to the sharp reduction in the mechanical properties of methane hydrate-bearing sediments (MHBS) caused by hydrate dissociation, the risk of formation failure in marine MHs exploitation is higher than that in conventional oil and gas exploitation. Formation failure in marine hydrate production probably leads to serious sand production or subsequent formation instability. A simplified and efficient analytical model is proposed at first for prediction of formation failure as well as the displacement around the wellbore during hydrate production, and then the reliability analysis for formation failure is performed by the Advanced First Order Second Moment Method based on the analytical solutions. This model considers the key factors affecting the formation failure, including 1) the partial coupling of multiple fields (the influence of pore pressure on mechanical field and the influence of hydrate dissociation on pore pressure, temperature and mechanical field), 2) the effect of gas/water or heat absorption caused by hydrate dissociation on pore pressure or temperature, 3) the change of mechanical properties of formation induced by hydrate dissociation and 4) the casing-formation interaction. The analytical solutions are verified and validated by numerical models. According to the analysis, the casing is sufficiently safe in the cross section due to its high stiffness, while the formation would be failure at the wellbore or dissociated front due to the stiffness/strength deterioration induced by hydrate dissociation. Hydrate dissociation leads to an increase in formation failure probability by approximately 20%. The probability of formation failure at the wellbore is about 30% higher than that at the dissociated front. The uncertainties in the internal friction angle and elastic modulus ratio have the greatest effect on formation failure probability.

Micro(nano)plastics in marine medaka: Entry pathways and cardiotoxicity with triphenyltin

The simultaneous presence of micro(nano)plastics (MNPs) and pollutants represents a prevalent environmental challenge that necessitates understanding their combined impact on toxicity. This study examined the distribution of 5 μm (PS-MP5) and 50 nm (PS-NP50) polystyrene plastic particles during the early developmental stages of marine medaka (Oryzias melastigma) and assessed their combined toxicity with triphenyltin (TPT). Results showed that 2 mg/L PS-MP5 and PS-NP50 could adhere to the embryo surface. PS-NP50 can passively enter the larvae and accumulate predominantly in the intestine and head, while PS-MP5 cannot. Nonetheless, both types can be actively ingested by the larvae and distributed in the intestine. 2 mg/L PS-MNPs enhance the acute toxicity of TPT. Interestingly, high concentrations of PS-NP50 (20 mg/L) diminish the acute toxicity of TPT due to their sedimentation properties and interactions with TPT. 200 μg/L PS-MNPs and 200 ng/L TPT affect complement and coagulation cascade pathways and cardiac development of medaka larvae. PS-MNPs exacerbate TPT-induced cardiotoxicity, with PS-NP50 exhibiting stronger effects than PS-MP5, which may be related to the higher adsorption capacity of NPs to TPT and their ability to enter the embryos before hatching. This study elucidates the distribution of MNPs during the early developmental stages of marine medaka and their effects on TPT toxicity, offering a theoretical foundation for the ecological risk assessment of MNPs.

QUANTITATIVE DETERMINATION OF THE STRENGTH OF ACTIVATED SLUDGE FLOCKS IN BIOLOGICAL TREATMENT TECHNOLOGIES

The performance of sludge and the effectiveness of wastewater treatment in various biological treatment facilities are influenced by the morphological features of activated sludge flocs. Currently, these features are assessed qualitatively through visual inspection, without statistical processing of the data. The article presents the results of quantitative determination of the strength of activated sludge flocs. A computerized method has been created to quantify the morphological characteristics of activated sludge flocs by analyzing sludge micrographs using the ImageJ software. Color and contrast indices were used to quantify the strength of the flocs. Photographs of activated sludge from the work of D. Eikelboom were used as standards for determining strength. In the calculations, we used photographs by D. Eikelboom taken at a magnification of 300 times (100 pixels) and 150 times (50 pixels). A laboratory study of the effect of Mg ions on the properties of activated sludge flocs was carried out when controlling the morphology of the flakes using the developed computerized technique. Examining the impact of Mg ions on activated sludge flocs revealed that higher magnesium concentrations in the sludge liquid result in increased linear dimensions (by 59%), floc area (by 81%) and floc volume (by 275%), but concurrently lead to a decrease in the strength of activated sludge flakes (by 21%). The obtained results in general indicated the positive effect of magnesium ion on the sedimentation properties of sludge in the aerotank-settlement system. A scale for quantitative determination of the strength of activated sludge flocs has been constructed. The developed computerized method enhances the precision and detail of visual evaluations of the technological attributes of activated sludge flocs, enabling the detection of even the smallest changes in the morphological characteristics across different wastewater treatment technologies. Keywords: activated sludge, flocs, concentration of magnesium, strength, technological characteristics.

Sedimentary record of microplastics in coastal wetland, eastern China

Microplastic (MP) dynamics can reflect history of plastic production and waste management in nearby areas. However, the stratigraphy of MPs in coastal wetlands and their link to policy and economic pattern changes are currently unclear. Here, MP stratigraphic records in sediment core from coastal wetlands in Yancheng, China, were used to reconstruct plastic pollution history. Neural network models simulated how policy intervention and economic development affected MP accumulation over time. We showed that MP abundance curves with boundaries from 1920 to 2019 had four stages. MP growth slowed or even decreased in the mid-to-late 1980s due to improved waste management and wastewater treatment since the late 1980s. Human activities were the primary factor affecting MP abundance and shape, followed by sediment properties. We predict that the environmental impact of MPs will continue to increase in the next decade. Current plastic policy measures focus on predictable waste emissions, but hidden sources like clothing fibers and tire wear that significantly contribute to MP pollution require further attention.

Sedimentary mud and phaeophytin-a are reliable predictors of oxygen consumption and nitrogen turnover in the southern North Sea

Coastal systems are exposed to variable human uses and anthropogenic pressures, yet they provide valuable ecosystem services. Understanding the benthic processes in these systems is crucial for their effective management and conservation. This study investigates sediment characteristics as proxies for oxygen and nitrogen turnover in coastal, sandy, permeable sediments. We incubated sediment samples to quantify the turnover of ammonium and nitrate and analyzed various sediment properties to determine the most suitable predictors of sediment reactivity. Oxygen consumption rates and rates of ammonium and nitrate turnover strongly correlate with mud content and phaeophytin-a, which are identified as the best proxies for sediment reactivity. Ultimately, our data show that sediment nutrient recycling and turnover is intimately linked to spring primary production in the water column. In order to deduce reaction rates of oxygen, ammonium and nitrate from sediment properties, we provide linear regression coefficients and their uncertainties, enabling access to previous observations that would otherwise remain inaccessible due to missing data. This study provides insights for the development of benthic models that ultimately can be used to assess the impact of anthropogenic pressures on coastal systems. The findings have implications for nutrient management and monitoring in the German Bight, as an improved understanding of sediment reactivity allows for more appropriate and sustainable management and monitoring policies to be implemented.

Benthic microbial biogeographic trends in the North Sea are shaped by an interplay of environmental drivers and bottom trawling effort

Microbial composition and diversity in marine sediments are shaped by environmental, biological, and anthropogenic processes operating at different scales. However, our understanding of benthic microbial biogeography remains limited. Here, we used 16S rDNA amplicon sequencing to characterize benthic microbiota in the North Sea from the top centimeter of 339 sediment samples. We utilized spatially explicit statistical models, to disentangle the effects of the different predictors, including bottom trawling intensity, a prevalent industrial fishing practice which heavily impacts benthic ecosystems. Fitted models demonstrate how the geographic interplay of different environmental and anthropogenic drivers shapes the diversity, structure and potential metabolism of benthic microbial communities. Sediment properties were the primary determinants, with diversity increasing with sediment permeability but also with mud content, highlighting different underlying processes. Additionally, diversity and structure varied with total organic matter content, temperature, bottom shear stress and bottom trawling. Changes in diversity associated with bottom trawling intensity were accompanied by shifts in predicted energy metabolism. Specifically, with increasing trawling intensity, we observed a transition toward more aerobic heterotrophic and less denitrifying predicted metabolism. Our findings provide first insights into benthic microbial biogeographic patterns on a large spatial scale and illustrate how anthropogenic activity such as bottom trawling may influence the distribution and abundances of microbes and potential metabolism at macroecological scales.

Hydraulic properties of sediments from the GC955 gas hydrate reservoir in the Gulf of Mexico

The economic feasibility of gas production from hydrate deposits is critical for hydrate to become an energy resource. Permeability in hydrate-bearing sediments dictates gas and water flow rates and needs to be accurately evaluated. Published permeability studies of hydrate-bearing sediments mostly quantify vertical permeability; however, the flow is mainly horizontal during gas production in layered reservoirs. Additionally, ASTM standards require a hydraulic gradient of 10–30 to be used during laboratory permeability measurements, but the gradient is much higher in the field, particularly near a production well. To address these issues, this study focuses on the hydraulic properties of a sandy silt subsample of the hydrate reservoir and a clayey silt subsample of the fine-grained, hydrate-free interbed recovered from a GC955 deep-water Gulf of Mexico gas hydrate reservoir. We characterize the sediment pore space with water retention curves for both hydrate-free and hydrate-bearing samples (hydrate saturation, Sh =80 %). Vertical deformation with increasing stress is also quantified while consolidating the samples to the 4 MPa in situ vertical effective stress. The customized permeameter measures both the horizontal and vertical permeability with increasing stress. Results show that high hydraulic gradients lower permeability in the flow direction, possibly due to increased flow tortuosity and local sediment compaction from the high seepage force. Assuming a single permeability value, even though hydraulic gradients decrease with distance from the well, is not realistic for field estimations. The results highlight that permeability anisotropy, hydrate saturation, stress conditions, and hydraulic gradient all substantially impact reservoir permeability during production.

Spatial distribution and population density of submerged aquatic vegetation in Shatt Al-Arab River

Submerged aquatic vegetation (SAV) is an integral component of aquatic ecosystems and provides essential habitats and ecosystem services. This study investigated the distribution and abundance of SAV in the Shatt Al-Arab River, located in Southern Iraq, and examined its relationship with changing environmental factors. Monthly surveys were conducted at three stations from October 2015 to September 2016 to assess the percentage cover of vegetation, biomass, and the physicochemical properties of water and sediment. Three SAV species belonging to the Potamogetonaceae family have been recorded. Canonical correspondence analysis showed a negative relationship between Potamogeton perfoliatus and depth/reactive phosphorus. The abundance of plants in this area was significantly lower than that reported in previous studies. Species richness and abundance were analyzed at all stations during the same period using biodiversity indices. The analysis revealed differences in species richness between the stations. This decline in abundance was likely due to increased salinity, nutrients, and anthropogenic pressures. This study demonstrates the impact of environmental changes on ecologically important SAV and emphasizes the necessity of implementing conservation and management strategies.

Geophysical Assessment of Coastal Erosion in Nigeria's Coastal Regions: Strategies for Protection and Management

The main purpose of this geophysical assessment was to learn as much as possible about how coastal erosion happens in Nigeria's coastal areas. The end goal was to come up with effective and efficient ways to manage and protect these areas. The research employed a variety of geophysical methodologies, such as GPR, electrical resistivity tomography (ERT), and bathymetric surveys, to collect essential data. GPR was utilized to examine the properties of soil and sediment beneath the surface. This investigation unveiled regions where soil cohesion was diminished, rendering them vulnerable to erosion. The organization ERT conducted a comprehensive analysis to determine the scope of saltwater intrusion and the dynamics of groundwater, with a specific focus on identifying areas susceptible to erosion. Bathymetric surveys were conducted to evaluate alterations in submerged topography and shoreline morphology over time, thereby elucidating patterns of shoreline regression. The assessments yielded significant insights into the vulnerabilities of coastal erosion, revealing distinct correlations among soil characteristics, saltwater intrusion, and shoreline alterations. The findings above provide a basis for the formulation of specific strategies to preserve and oversee Nigeria's susceptible coastal areas, thereby fostering the sustainable management of coastal ecosystems and ensuring the protection of coastal communities.

Internal loading of phosphorus in streams described by a Sediment-Water Exchange Model for Phosphorus (SWEMP): From lab to field scale

The reaction of phosphorus (P) between sediments and water in streams strongly affects the surface water P concentrations. A new reactive transport model (SWEMP: Sediment-Water Exchange Model for Phosphorus) was developed to describe redox dependent P sorption in the sediment and vertical diffusive transport of solutes to the overlying stream. The model parameters were independently obtained to first predict P release in ten different sediment-water batch systems and in two flumes. Input parameters are the degree of P saturation of the sediment, its organic matter content, dissolved oxygen (DO) concentration and temperature. The dissolved P concentrations in the overlying waters ranged from 0.02 to 1.2 mg P L−1 in these systems and were correctly predicted by the model within, on average, a factor 1.3 (batch) or 1.1 (flume). The P flux from the sediment towards the overlying water increased with increasing sediment P:Fe ratio and respiration rates, and with decreasing DO and water pH. After validation of the model with experimental data, it was used to predict monthly P concentrations in Flemish rivers using the total P emission data, total discharge, average sediment properties and the monthly averaged water temperatures, DO concentrations and electric conductivity. The monthly average P concentrations oscillate annually between 0.24 and 0.73 mg P L−1 and predictions matched the long-term monitoring data within 10 % using only one adjustable parameter for the entire water system (N > 250,000). The model predicts that summer peaks in P are related to internal loading from the sediment under anoxic conditions rather than to emission-dilution effects, i.e. external input of P and/or its concentration at lower flow rates. This suggests that, surface water P concentrations can be lowered by enhanced DO in the water, the addition of Fe and Al rich binding agents to the sediments and by reducing P emissions.

Analysis of hydro-abrasive erosion in a high-head Pelton turbine injector using a Eulerian-Lagrangian approach

High-head hydropower plants deploy Pelton turbines to harness energy; however, turbine components face severe abrasive erosion due to suspended sediments. The erosion of the Pelton injector leads to the degradation of the jet quality, reducing the turbine efficiency considerably. Recently, the erosion of an internal servomotor design of the injector has been studied numerically; however, the cavitation-erosion synergy was not explored. This study serves as the extension of the literature with an analysis of the hydro-abrasive erosion and inception of cavitation in an injector with an external servomotor of a high-head hydropower plant (HPP). A Eulerian-Lagrangian approach is used to study the effects of sediment properties and flow parameters on hydro-abrasive erosion; whereas, the Schnerr-Sauer model is used to analyze the inception of cavitation. Interestingly, an increase in particle size from 40 microns to 200 microns resulted in a 95.7% reduction in needle erosion; but, led to a two-fold increase in nozzle erosion. For an increase in the plant head from 200 m to 820 m, the increase in erosion rate of the nozzle and the needle is 4.36 and 1.4 times, respectively. Moreover, the possibility of cavitation in the Pelton injector also increases with an increase in the head of the HPP leading the injector to higher susceptibility to the synergic effect of cavitation and hydro-abrasive erosion. This study attempts to assist the hydropower development in high-head regions with a risk of high sediment flow and manage the existing plants efficiently.

Numerical simulation of elastic properties of hydrate-bearing sediments with digital rock technology

The elastic properties are crucial rock physics properties in the exploration and reserve evaluation of hydrate reservoirs. However, accurately describing the evolution of these properties is a complex task due to the influence of numerous factors, such as particle properties, matrix components, sediments framework, and the distribution of natural gas hydrates within the pores. Existing empirical models often exhibit limitations in adequately capturing the effect of these factors, hindering a comprehensive understanding of the elastic behavior of hydrate-bearing sediments. In this study, the digital rock method was applied to analyze the impact of four factors, which include porosity, particle size, clay components, and the hydrate distribution morphology, on the elastic properties of sediments. The applicability of three theoretical models, namely the time-averaging equation, cementation theory, and three-phase Biot equation, in characterizing the effects of these factors was evaluated. Finally, the numerical simulation results were used to offer a comprehensive characterization of the range of variation in sediment elastic properties under each category of influencing factors. The results indicate that the applicability of the uncemented-sand model is dependent on the initial porosity of the sample, while the cemented-sand model is not a reliable predictor of the shear modulus. On the other hand, the simplified three-phase Biot equation exhibits good coverage of the simulated data at hydrate saturations exceeding 30%. Moreover, the distribution of hydrates can be effectively determined by adjusting the model parameters. The findings from this study contribute to a better understanding of the impact of these factors on sediment elastic properties and have important implications for the exploration and assessment of hydrate reservoirs.

High efficiency regulating sedimentation and rheological properties of copper tailings using polycarboxylate superplasticizers

The recovery of low grade and fine particle copper ore usually requires sufficient dissociation, which reduces the particle size to the submicron level, presenting new challenges in subsequent copper tailings disposal. Flocculants can improve tailings sedimentation efficiency, but they also change the rheological properties of the slurry, resulting in low efficiency and high energy consumption during long-distances pumping. To address this issue, this study introduced polycarboxylate ether (PCE) superplasticizers as auxiliary additives for tailings treatment to improve fine particles sedimentation efficiency while enhancing slurry flowability. The results showed that compared to non-ionic polyacrylamide (NPAM) treated slurries, the synergistic effects of PCE and NPAM increased the initial sedimentation rate (ISR) by up to 3.4 times while decreasing the yield stress by up to 8 times and the thixotropic loop area by 10.5 times. DLVO theory calculations showed that PCE mainly affects particle interactions through a significant decrease in electrostatic repulsion. By in-situ monitoring with a focused beam reflectance measurement (FBRM) device, it was demonstrated that the synergistic effect of PCE improved the flocculation ability, strength, and regrowth ability of flocs. Furthermore, strong correlations were found between floc properties and fluid rheological properties. Overall, this study indicated that PCE additive was a promising reagent for fine particles slurry rapid settling and flowability enhancement, providing a new approach for copper tailings disposal.

Investigating the influence of particle size ranges on the physical, mineralogical, and environmental properties of raw marine sediment

Annually, over one billion cubic meters of sediments are dredged worldwide. The field of construction suffer shortage of natural resources, these sediments present a potential local resource in various regions. Amongst the sectors, road construction stands as the largest consumer of aggregates, making the recovery of sediments an appealing solution. The dredged sediments made of three phases: solid, liquid, and air. The solid phase contains both mineral and organic components, each with particle size ranges. Particle size is a well-known factor significantly impacting material characteristics.This study's primary objective is to compare sediment particle size ranges as sub materials, particularly focusing on their classification for sediment recovery in road construction. The preparation of sediments for characterization tests in this context necessitates specific drying procedures, prompting an investigation into the effects of drying methods. Three distinct drying techniques-air drying, freeze drying, and oven drying were employed.Particle size ranges were extracted from raw marine sediment and categorized based on the following diameter ranges: 2–0.4 mm; 0.4–0.180 mm; 0.180–0.063 mm; and < 0.063 mm. Comprehensive physical, environmental, and chemical characterizations were conducted. The pivotal findings of this study unequivocally reveal variations in the distribution of organic matter across these different fractions. Notably, the fine fraction exerts a substantial influence on material-level attributes, especially concerning environmental characterization. Moreover, the choice of sample drying method before testing introduces variable effects on the investigated attributes. environmental impact analyses using leaching tests indicated higher values of elements like Barium (Ba), Molybdenum (Mo), Fluoride (F), and Chloride (Cl) in sediment fractions below 0.063 mm. The DRX analyses appear that the fine fraction had few clay particles, and higher values measured on different test were associated with organic matter.

Spatial distribution and partition of polycyclic aromatic hydrocarbons (PAHs) in the water and sediment of the southern Bohai Sea: Yellow River and PAH property influences

The marginal Bohai Sea, connected to the northwestern Pacific Ocean, is threatened by human activity. The Yellow River, the second largest river in China, drains large amounts of water, silts, and polycyclic aromatic hydrocarbons (PAHs) into the southern Bohai Sea; however, to what extent the Yellow River inputs influence the spatial distributions and partitions of PAHs in the southern Bohai Sea is not well known. Therefore, this study collected surface water, bottom water, and sediment samples from the southern Bohai Sea and analyzed them to examine the spatial distributions and partitions of 15 priority PAHs. The results showed that PAH concentrations ranged from 26.9 to 50.1 ng L–1 in surface water, 18.8 to 44.1 ng L–1 in bottom water, and 7.4 to 143.9 ng g–1 in sediment, with higher proportions of four-, five-, and six-ring PAHs in sediment than in water. PAH inputs from the Yellow River and sea coastal currents determined the spatial distribution of PAH concentrations in water and sediment, with an overall decrease from the estuary to the southeast. However, the solid dilution effect of input silts from the Yellow River and the liquid dilution effect of water from the Yellow River and Yellow Sea led to lower PAH concentrations in the water and sediment of the southern Bohai Sea than those in other areas of the Bohai Sea. PAH exchange between the atmosphere and seawater led to significantly higher individual PAH concentrations (except for acenaphthylene) in the surface water than in the bottom water, with ratios significantly related to the PAH n-octanol-water partition coefficient, organic carbon-water partition coefficient, and Henry's law constants. These parameters also determined PAH partitioning between the bottom water and sediment. Individual and total PAH concentrations in the sediment were significantly correlated with organic matter, clay, and silt contents. Therefore, the partitions and spatial distributions of PAHs in the southern Bohai Sea comprehensively depend on PAH properties, PAH inputs from the Yellow River and the atmosphere, sea currents, and seawater and sediment properties. The ecological risks posed by individual PAHs in both water and sediment were negligible or acceptable.

Geological Aspects of the Formation and Distribution of Gas Anomalies in Bottom Sediments of the New Siberian Sedimentary Basin and Adjacent Geostructures of the East Siberian Sea

Abstract —In bottom sediments of the New Siberian sedimentary basin and adjacent geostructures of the East Siberian Sea, we identified СН4, as well as its limit and unsaturated homologues (up to and including C5H12), CO2, CO, H2, He, H2S, O2, N2, and Ar. Isotope-gas-geochemical parameters δ13С СО2, СН4 and С2Н6, of the molecular mass of hydrocarbon fraction and genetic coefficients indicate the presence of both syngenetic and epigenetic gases of various gas sources in sediments, including recent sediments, peatlands, coal-bearing and gas-bearing formations, solid bitumen, igneous formations, accumulations of gas hydrates and prognostic condensate-gas, condensate, oil-and-gas and gas-and-oil reservoirs. Concentrations of CO2 and CO reach 29.25 and 0.06 cm3/kg, CH4 and the sum of its homologues – 5.93 and 0.031, Н2 and He – 0.78 and 0.318, H2S – 0.092 cm3/kg; this indicates that gas-geochemical anomalies, exceeding the anomaly criteria by 6–124 times, form in bottom sediments. The formation and distribution of abnormal concentrations of natural gases depend on the complex influence of gas-controlling factors – geological structure, fold and fault tectonics, magmatism, coal-oil-gas content, bituminous content, organic saturation, lithological composition, water-physical and reservoir properties of sediments, hydrogeological, geocryological and other conditions for accumulation of natural gases or their degassing.

Geoacoustic and geophysical data‐driven seafloor sediment classification through machine learning algorithms with property‐centered oversampling techniques

AbstractThis study aims to classify seafloor sediments using physics‐inspired and data‐driven soil models combined with machine learning algorithms and oversampling techniques. The field data used for the input variables include porosity, S‐ and P‐wave velocities and depth. The soil information reported in the original literature and the “six reference sediments” and effective stress‐versus‐depth models proposed by the previous study confirm the sediment type across all of the input variables. We use three machine learning algorithms and four oversampling methods to enhance the performance accuracy and overcome data imbalance in the minority class. The results show that the averaged accuracy of sediment classification with original data corresponds to 0.88 for porosity, 0.61 for S‐wave velocity, and 0.97 for P‐wave velocity. In particular, the enhanced accuracy with oversampled input variables becomes more pronounced when the depth data are considered in a dataset. The class‐oriented grouping method newly proposed in this study appears to be a robust approach to enhancing performance. Surprisingly, model‐based input variables lead to the best performance in all cases. The proposed analyses conducted using machine learning algorithms and oversampling techniques within the physics‐inspired models could be extended to obtain a first‐order assessment of marine sediment properties.

High efficiency and mechanisms of Cd2+, Cu2+, Mn2+ removal from aqueous solution by modified tobermorite

In this work, nanoscale magnesium oxide and activated carbon were simultaneously loaded on tobermorite through a gelation-calcination method. The new composite (TOB@C@MgO) was used as an effective adsorbent to remove Cd2+, Cu2+, and Mn2+ from aqueous solution and actual wastewater. Its specific surface area was determined to be 146.90 m2/g, and its sedimentation property was found to be satisfactory. At an initial ion concentration of 500 mg/L, a solution pH of 5.2 ± 0.2, an adsorbent dosage of 1.5 g/L, and a temperature of 25 °C, the adsorption equilibrium for Cd2+, Cu2+, and Mn2+ was reached within 2 h, 4 h, and 6 h, with a removal efficiency of 100 %, 90 %, and 64 %, respectively. The pseudo-second-order model and Langmuir model fitted the kinetic and isothermal adsorption data well. The maximum adsorption capacity for Cd2+, Cu2+, and Mn2+ by TOB@C@MgO, as calculated from the Langmuir model, was 1000.00 mg/g, 526.32 mg/g, and 416.67 mg/g, respectively. The selective sequence of metal ions by TOB@C@MgO was in the order of Cd2+ > Cu2+ > Mn2+. Besides, TOB@C@MgO demonstrated effective treatment of actual wastewater, and exhibited reasonably good reusability and stability. Different characterizations revealed that Cd2+, Cu2+, and Mn2+ removal by TOB@C@MgO was primarily dominated by ion exchange. Surface precipitation/complexation, interaction with π electrons, and physical adsorption also contributed to the fixation of Cd2+, Cu2+, and Mn2+ onto the surface of TOB@C@MgO.

ANALYSIS OF BUILDING A FACIES MODEL OF A RESERVOIR USING THE RESULTS OF INTERPRETATION OF SEISMIC DATA

Forecasting changes in the characteristics of sediment properties is an urgent task at all stages of exploration and development of deposits. Remote sensing techniques for sediment research, such as seismic surveys, are now becoming a prerequisite for a full study of the study area. The problems that need to be solved are not limited to the construction of a structural-tectonic model. It is necessary to look for opportunities to predict filtration and capacitance properties (PP) in the interwell space. This will improve the quality of forecasting reservoir development zones for complex reservoirs, which will result in optimization of production drilling and reduction in the risks of drilling unproductive wells. The deposits considered in this work are represented by terrigenous sediments. When developing oil-saturated intervals, water and gas breakthroughs are expected, which are especially typical for high-permeability intervals. The commercial characteristics of sediments depend on many factors, including formation conditions. Knowledge of the sedimentation environment greatly facilitates the task of predicting reservoir rocks at all stages of field development.The paper presents the results of constructing a facies model using the results of inversion transformations of seismic surveys and interpretation of GIS (geophysical surveys in wells). When creating a facies distribution model, a probabilistic assessment of the presence of a particular facies in the study area was used.In previous works, the facies model was accepted conceptually. Its influence on the final geological model and assessment of hydrocarbon reserves was indirect. The facies model presented in the article does not conceptually contradict the previously accepted one. That is, the concept of sediment formation has been preserved, but its influence on the geological model has changed. This allows you to more accurately display the geological structure of layers and optimize technological solutions when developing an operational facility.After the work was completed, more than thirty-five wells were drilled. Based on the results of the assessment of new wells, the percentage of confirmation of the forecast of facies distribution along the wellbore with the actual data of new drilling (facies identification according to GIS data) is more than 60–65 % for the entire study area.