Dominant Influencing Factor Research Articles

Adsorbent Properties of Porous Boron Nitride and Activated Carbon: A Comparative Study.

Porous boron nitrides possess beneficial properties such as high thermal and chemical stability which are critical for applications in adsorption processes. In order to assess possible fields of applications, trace-level adsorption isotherms of different hydrocarbons on two synthesized porous boron nitrides and two commercial activated carbons are compared. By normalizing the adsorptive loadings on the micropore surface area, superior adsorption performances of the BN materials on polar and aromatic adsorptives with up to 50% higher loadings compared to the activated carbons can be shown. Nonpolar adsorptives, on the other hand, feature higher specific loadings on the activated carbon. Consequently, the size of the micropore surface appears to be decisive for nonpolar adsorptives, while the higher polarity of the boron nitrides is the dominant influencing factor for the adsorption of polar and aromatic components. For an energetic study of the adsorbents, calorimetric experiments were performed to identify and discuss adsorbent-adsorptive interactions. While the initial heat of adsorption of the nonpolar n-hexane is lower on the boron nitride than on the activated carbon due to a less favorable spatial arrangement, toluene shows comparable values on both adsorbent classes and the polar acetone shows higher values on the polar boron nitride. Considering technical applications in adsorption technology, the thermal stability of the boron nitrides is investigated using spontaneous ignition temperatures and points of initial oxidation. Here, the porous boron nitrides with oxidation temperatures above 900 °C show about 400 °C higher values and thus a significantly higher thermal stability.

Effects of Climate Changes and Crop Phenological Responses on Soil Organic Carbon of Cultivated Land in Fujian Province

Research on the mechanism of how climate change affects cultivated soil organic carbon is the basis for the management of cultivated land quality in the context of climate change. Crop phenological responses to climate change have an important effect on cultivated soil organic carbon as well. However, previous research primarily focused on the independent effects of climate change or crop phenological responses on the changes in soil organic carbon, and few studies have analyzed the changes in cultivated soil organic carbon under the combined influence of both factors or quantified their contribution rates to the changes in cultivated soil organic carbon. Based on topsoil samples in 2008 and 2021, annual pre-season and mid-season climate data from 2008 to 2021, and the phenological parameters extracted from the enhanced vegetation index （EVI） time series from 2007 to 2022, a soil organic carbon predictive model was constructed using the random forest algorithm. The total change in soil organic carbon from 2008 to 2021, the change in soil organic carbon under climate change alone, and the change in soil organic carbon under the synergistic influence of climate change and crop phenological responses were simulated. Furthermore, the contributions of climate change and crop phenological responses to the changes in cultivated soil organic carbon were distinguished and quantified. Moreover, the dominant influencing factors of soil organic carbon changes and their spatial distributions were identified and analyzed. The results were as follows： ① Under the synergistic influence of climate change and crop phenological responses, a decrease was observed in soil organic carbon in 74.15% of the cultivated land area in Fujian Province during the years 2008-2021, with an average decrease of 2.20 g·kg-1. Additionally, there was an increase in soil organic carbon in 25.85% of the cultivated area, with an average increase of 1.48 g·kg-1. ②The average contribution rates of pre-season climate, crop phenological responses to climate change, mid-season climate, and phenological changes resulting from cultivars shifts or other adjustments of agricultural measures to soil organic carbon changes were 34.08%, 28.56%, 22.75%, and 14.61%, respectively. Overall, climate change had a greater impact on the changes in cultivated soil organic carbon in Fujian Province than the crop phenological response to climate change. ③ The regions where climate change and phenological response jointly acted as dominant influencing factors held the largest area, accounting for 47.06% of the total cultivated land area in Fujian Province, and the regions where climate change was the dominant influencing factor alone held the second-largest area, accounting for 28.64% of the total cultivated land area. ④ Higher contribution rates of pre-season climate factors and phenological changes resulting from cultivar shifts or other adjustments of agricultural measures tended to be distributed in higher-altitude areas, whereas higher contribution rates of mid-season climate factors and phenological responses to climate change tended to be distributed in lower-altitude areas. These research findings can provide a theoretical basis for decision making regarding the management of cultivated land quality and the safeguarding of food security in the context of climate change.

Untangling the coupling effect of water quality and quantity on lake algal blooms in Lake Hulun from a dual perspective of remote sensing and sediment cores

Algal blooms and sediment diatoms are crucial indicators of lake water ecology, influenced by water quantity and quality. However, the coupled effects of water quality and quantity changes on algal blooms are still unclear, especially for lakes in cold and arid regions. This study assessed the long-term variations in algal blooms in Hulun Lake using a novel approach combining remote sensing and sediment core samples for diatom analysis. Two mutation points from the structural change test were identified in approximately 2000 and 2010 for algal bloom area (MBE) and sediment diatom richness, indicating asynchronous algal blooms. A structural equation model (SEM) demonstrated that water level (WL) changes were the dominant influencing factor, co-driving the variations in algal blooms and sediment diatoms in conjunction with total nitrogen (TN), total phosphorus (TP), and chemical oxygen demand (COD). The results revealed nonlinear relationships between the lake WL, TN, Chla, and COD. The water level of 543 m emerged as a critical threshold affecting the relationship between water quality and quantity. Distinct differences in this relationship were observed when water levels were above or below this threshold. These variations became particularly pronounced during periods of high and low water levels. The results provide novel insights into the dynamics of algal blooms and can further support lake ecosystem conservation and management.

Evolution and driving mechanism of multiple ecosystem services in resource-based region of Northern China

Understanding the spatiotemporal characteristics and comprehensive service capabilities of various ecosystem services is crucial for maintaining regional ecosystem security, and clarifying the driving mechanisms of ecosystem services plays a guarantee for achieving regional sustainable development. Based on the ecological issues of Shanxi Province (SXP) in China, an assessment system covering eight targeted ecosystem services were constructed to quantitatively analyze the spatio-temporal patterns and contribution rates of driving factors. The water conservation, sand fixation, environment purification and habitat quality in the Loess Hills of western SXP have improved, with significant increase in hotspots. The comprehensive service capacity of ecosystem services in the Fenwei Basin (central SXP) has deteriorated, and the coldspots have expanded. The water conservation, carbon storage, habitat quality and recreation culture in the Yanshan-Taihang Mountains (eastern SXP) were enhanced, while product supply, carbon storage and environment purification were deteriorated. Land use is the dominant influencing factor on product supply. Water and soil conservation, sand fixation, and environment purification are dominated by climate factors. Carbon storage, habitat quality and recreation culture are influenced by underlying surface conditions. The current study provided a research paradigm, which will help the government with appropriate management policies to ensure the effectiveness of ecological protection and restoration, and offers insights for facilitating ecological sustainability and economic transformation in resource-based regions worldwide.

Adherence of inactivated polio vaccine immunization for children in Central Java Province

Indonesia is a country with high-risk polio transmission. Administering inactivated polio vaccination (IPV) after drops-polio or oral polio vaccination (OPV) was a strategy stopping polio transmission because its ability to ward off poliovirus which was very dangerous. The IPV coverage was very low and have never reached the target since it was launched in 2016. The study purpose was analyzing determinants factors of IPV adherence. A cross-sectional survey conducted in 31 districts in Central Java Province. Sample was 685 children aged 11-23 months and selected using purposive and accidental sampling method. Collecting data by interview using structured questionnaire and observation with maternal and child health (MCH) Handbook to identify immunization status. The collected data was analyzed univariate, bivariate, and multivariate. As many as 74.3% of children received IPV. Partially, variables of delivery history, immunization status, knowledge, attitudes, sources of information, and service satisfaction were related to IPV adherence. Simultaneously, immunization status, attitudes, and sources of information influenced IPV adherence with an overall effect 35.2%. Immunization status as the dominant influencing factor. Efforts were needed reducing resistance to IPV through psychological approach that was motivating and personal, also using of social media as a medium for positive information and communication, in addition to improve immunization service system.

Determinants of Receptivity Towards Entomophagy among Young Adults

This research focuses on understanding the factors influencing the acceptance of entomophagy in Morelia, Michoacán. The study involves a survey aimed at two distinct groups of young adults aged 18 to 29 (control and experimental), a demographic known for being open to evolving food preferences. The results revealed interesting differences in preferences between individuals who have and have not tried insect-based foods. Surprisingly, the price did not emerge as a dominant influencing factor. The study suggests entomophagy can be a viable and accepted dietary option when relevant information is easily accessible, potentially reducing neophobia levels.

What Are the Variation Patterns of Vegetation and Its Influencing Factors in China from 2000–2020 from the Partition Perspective?

China’s vegetation ecosystem has undergone profound changes, and there is an urgent need to explore the mechanisms behind vegetation changes in different ecological sub-regions and historical periods across China. Based on NDVI (normalized difference vegetation index) data, this study analyzed the spatial and temporal evolution patterns and driving mechanisms of six ecological sub-regions in China. The results showed that: (1) over the past 20 years, the vegetation coverage in mainland China showed a decreasing trend from east to west. (2) Over the past 20 years, the vegetation coverage of the six ecological sub-regions showed an increasing trend, with the highest increase in Central Southern China (0.0039) and the lowest increase in East China (0.002). (3) The gravity center of Northeast China showed a trend of migration to the northwest. The gravity center of North China, East China, and Central South China showed a trend of migration to the southwest, while that of Northwest and Southwest China showed a trend of migration to the southeast. (4) During the period from 2000 to 2020, vegetation cover levels showed an upward trend. (5) The lag time of vegetation types in different regions was different. (6) Precipitation was the dominant influencing factor in the evolution of vegetation in Northeast China, North China, Northwest China, and Southwest China. The dominant influencing factors of vegetation evolution in East China were land use and GDP (gross domestic product), while the dominant influencing factors of vegetation evolution in Central South China were precipitation and land use.

Preparation of lignin-based porous carbon through thermochemical activation and nitrogen doping for CO2 selective adsorption

Preparing CO2 adsorbents from biomass feedstock has garnered considerable attention due to its potential for fostering sustainable, economic, and eco-friendly development. Introduction of nitrogen-containing functional groups can enhance the affinity for CO2 of biochar but also inevitably affect the pore structure. The challenge lies in ascertaining and regulating the effect of N-doping on the pore structure. In this work, lignin was activated using KOH, and then followed by urea N-doping through pyrolysis or hydrothermal methods. At small dosages of KOH (the mass ratio of KOH/lignin = 0.25), in addition to introducing nitrogen-containing functional groups, urea modification boosted pore volume of <1 nm favorable for CO2 adsorption through etching carbon skeleton, while the small dosage of KOH reduced its inherent corrosive hazards. Correlation analysis showed that the dominant influencing factor for CO2 adsorption at ambient temperature and pressure was the pore volume with pore size of 0.6–0.8 nm, whereas nitrogen content (especially N-5 content) was the main influencing factor at high temperatures (50 °C) and low pressures (0.15 bar). The peak enhancement of the C–N bond under the CO2 adsorption at 50 °C by in situ diffuse reflectance infrared Fourier transform test indicated that the nitrogen-containing functional groups have a chemisorption effect on CO2. The adsorbent PK-0.25-HU exhibited adsorption capacity of 4.46 mmol/g (25 °C, 1 bar), 2.97 mmol/g (50 °C, 1 bar). Dynamic separation coefficient of CO2/N2 reached 93.82 in a gas mixture of CO2/N2 = 15 %/85 %.

Factors Associated With the Spatial Distribution of Severe Fever With Thrombocytopenia Syndrome in Zhejiang Province, China: Risk Analysis Based on Maximum Entropy.

Severe fever with thrombocytopenia syndrome (SFTS) is an emerging infectious disease that was first identified in mainland China in 2009 and has been reported in Zhejiang Province, China, since 2011. However, few studies have focused on the association between ticks, host animals, and SFTS. In this study, we analyzed the influence of meteorological and environmental factors as well as the influence of ticks and host animals on SFTS. This can serve as a foundational basis for the development of strategic policies aimed at the prevention and control of SFTS. Data on SFTS incidence, tick density, cattle density, and meteorological and environmental factors were collected and analyzed using a maximum entropy-based model. As of December 2019, 463 laboratory-confirmed SFTS cases were reported in Zhejiang Province. We found that the density of ticks, precipitation in the wettest month, average temperature, elevation, and the normalized difference vegetation index were significantly associated with SFTS spatial distribution. The niche model fitted accurately with good performance in predicting the potential risk areas of SFTS (the average test area under the receiver operating characteristic curve for the replicate runs was 0.803 and the SD was 0.013). The risk of SFTS occurrence increased with an increase in tick density, and the response curve indicated that the risk was greater than 0.5 when tick density exceeded 1.4. The risk of SFTS occurrence decreased with increased precipitation in the wettest month, and the risk was less than 0.5 when precipitation exceeded 224.4 mm. The relationship between elevation and SFTS occurrence showed a reverse V shape, and the risk peaked at approximately 400 m. Tick density, precipitation, and elevation were dominant influencing factors for SFTS, and comprehensive intervention measures should be adjusted according to these factors to reduce SFTS incidence in Zhejiang Province.

Effect of channel morphological changes on wetland transformation

Keeping aside the traditional approaches to investigating floodplain wetland transformation, the current study investigated various aspects of it through changes in river channel morphology and drainage pattern. The study analyzed wetland transformation using satellite image-based machine learning and intensive fieldwork. Ordinary Least Square (OLS) regression was applied to identify dominant influencing factors among 24 contributing factors under six clusters to eight dependent phenomena of transformation. The result showed that 57 % of wetland area lost since 1991, and existing wetland has also experiencing hydrological scarcity. From 1991 to 2021, the area under low water depth (<1 m.) inflated from 18.55 % to 50.54 %, the hydro-period narrowed down, and the appearance of water become inconsistent. The OLS result showed that changes in channel morphology (bottle neck channel, embankment-driven carrying capacity enhancement, etc.), interruptions in river and wetland connecting channels (source closure, breaching the continuity, conversion in to agricultural land, etc.), and changes in flood ambience (regulated by dam construction, erection of embankments, etc.) majorly contributed to wetland transformation. Very high explainability was found in the cases of rate of wetland loss, decreasing water depth under greater depth, narrowing hydro-period (R2 > 0.9). The findings of this work would be a good policy document for floodplain wetland management.

Prevention of HIV Transmission Among Men Who Have Sex with Men and Compliance with Sexual Protective Equipment

Sexual orientations, such as gay, lesbian, and bisexual, are prevalent among individuals at high risk of experiencing mental health problems, including drug use, depression, emotional distress, and suicide. Therefore, this study aimed to assess the compliance of men who have sex with men with protective equipment and determine the dominant influential factors. This cross-sectional study included 187 men who had sexual intercourse with men who were recruited from two foundations based in Palembang City, Indonesia, focusing on people living with HIV/AIDS. Data were analyzed using Chi-square and binomial logistic regression. In this context, 50.8% of men who have sexual intercourse with men did not comply with the use of sexual protective equipment, exceeding those in compliance. The multivariate logistic regression showed that knowledge was the dominant factor (PR = 15.733; 95% CI = 4.063-60.920), and most low-knowledge individuals were 15.733 times more at risk of non-compliance. Intensive education is needed regarding the potential risk of transmission, considering the ease of access to condoms.

Assessing Users’ Demand for Library Space: Insights from an Architecture School

The purpose of this paper is to conduct a post-occupancy evaluation to assess users’ feedback on the use of the architecture school library at Thammasat University, Thailand. The proposed study also has a specific objective: to explore users’ demand for library space in terms of academic library attributes. A case study of the library in the Faculty of Architecture and Planning was conducted at Thammasat University. Multiple data collection methods were used, including document analysis, a questionnaire survey, a workshop, and focus group interviews, to gather information on users’ demand for the library space. The findings confirm the relevance of the variables in the conceptual model from previous studies, which encompass three key attributes regarding users’ demand for library space: physical, social, and digital spaces. Functional obsolescence and changing learning approaches are revealed as dominant influential factors affecting users’ demand for library space. The connection between post-occupancy evaluation (POE) and pre-design evaluation (PDE) in the redevelopment of a real estate project is considered as a shift from performance measurement to performance management, assisting in establishing agreed-upon performance goals for the operation. This study’s findings, derived from a single case study, do affect affect generalisability. However, the study provides insights into academic library design and renovation by emphasising the alignment of library spaces with user needs for improved service effectiveness and user satisfaction. The research introduces an integration of POE and PDE, proposing a methodological framework for future library space redevelopment that could contribute to the broader discussion on library design and user experience.

Diversified evolutionary patterns of surface urban heat island in new expansion areas of 31 Chinese cities

As a hot area of population inflow in the process of urbanization, the urban expansion area faces rapid growth of surface urban heat island (SUHI). However, the multi-dimensional evolutionary characteristics of SUHI in urban expansion areas are still unclear. Through analyzing the evolution of SUHI range ratio, mean intensity and maximum intensity, in this study we identified the comprehensive evolutionary pattern of summer SUHI in urban expansion areas of 31 major cities in China during 2000–2018, and further investigated the corresponding dominant influencing factors. The results showed that the SUHI range and intensity in urban expansion areas exhibited a significant increasing trend in 81% and 71% of the cities respectively during the summer daytime. The cities with declining SUHI range and intensity were distributed in northwestern high-altitude areas with low economic level, while the cities with dominant increases in the SUHI range were distributed in eastern low-altitude areas with high economic level. Climate conditions and population distribution were the dominant influencing factors of intensity-dominated increasing and balanced increasing types, respectively. The intensity and range two-dimensional increasing type had experienced the most severe SUHI growth, with large proportion of secondary industry as the main influencing factor. This study highlighted the importance of multi-dimensional characteristics of SUHI evolution, which provided a new insight to understand SUHI change in urban expansion areas and associated mitigation measures.

Determinant Factors of Diabetes Prevention Behavior in Students with Diabetes Mellitus Risk

Background: The trend of diabetes cases has shifted to younger ages, starting at the age of 15 years old, due to unhealthy lifestyles. Researchers have discovered that health students also tend to have a poor lifestyle. Students are associated with emotional activity and busyness, but no research has examined the relationship between these conditions and diabetes prevention behavior. Purpose: This study examined determinant factors affecting diabetes prevention behavior in college students with diabetes mellitus risk.Methods: This study used a cross-sectional design, utilizing random sampling to gather data from 209 college students with diabetes risk. The instruments used in this study included adaptations of the Diabetes Prevention Behavior questionnaire, the modified Diabetes Management Time Questionnaire (DMTQ), the Perceived Behavioral Control, and the Trait Emotional Intelligence Questionnaire. Data analysis encompassed One-way ANOVA, Mann-Whitney, Kruskal-Wallis, Spearman’s rank, and multiple linear regression.Results: The study found a significant relationship between diabetes management time (p=0.001) and emotional intelligence (p=0.000) with diabetes prevention behavior. Emotional intelligence emerged as the dominant influencing factor (B=0.332). Conversely, no significant relationships were observed between perceived behavior control (p=0.223), class (p=0.734), sex (p=0.231), study major (p=0.263), age (p=0.064), and diabetes mellitus risk (p=0.664) with diabetes prevention behavior.Conclusion: This study revealed a significant relationship between diabetes management time, emotional intelligence, and diabetes prevention behavior. Emotional intelligence emerged as the key factor affecting diabetes prevention behavior, highlighting the need for focused interventions to enhance emotional intelligence and improve diabetes management among college students.

Investigating the Spatial, Proximity, and Multiscale Effects of Influencing Factors in the Snowmelt Process in the Manas River Basin Using a Novel Zonal Spatial Panel Model

It is essential to investigate the influences of environmental elements on snow cover to understand the mechanism of the snowmelt process. These elements, as influencing factors, have spatial heterogeneity, which results in significant differences and uncertainties in the extent and range of their effects at different scales. However, little research has been conducted on the spatial interaction and mechanisms of these factors at multiple scales. This study selected the Manas River basin in the Tianshan Mountains as the study area. The study period is 2015–2020. The snow cover status index is calculated based on available Landsat8-OLS/TIRS data; influencing factors are collected from multiple datasets. Their relationships are explored using a novel zonal spatial panel model, fully considering the spatial, proximity, and scale effects. The findings are as follows: (1) There is a robust spatial interaction and proximity effect between snowmelt and various factors, and such effects display distinct spatial heterogeneity. The elevation (ELE), slope (SLP), land surface temperature (LST), and normalized digital vegetation index (NDVI) showed significant overall dominant effects on the snow melting process. The influencing factors with apparent proximity effects are LST, ELE, SLP, NDVI, and air temperature (TEMP), and their influence ranges are different. (2) The relative importance and significance rank of dominant influencing factors vary under different partition schemes and scales. As the scale decreases, the significance of terrain- and vegetation-related factors increases, whereas the significance of temperature- and elevation-related factors decreases, and the number of dominant factors also decreases. (3) The influencing factors represent distinct characteristics among each zone at the optimally partitioned scale we defined. The overall influencing pattern demonstrates a characteristic of being globally dictated by elevation and temperature, with local terrain factors, vegetation, and wind speed modifying this pattern. Our study provides practical data support and a theoretical basis for deepening our understanding of the influence mechanism of the snow melting process.

Exploring the connection between morphological characteristic of built-up areas and surface heat islands based on MSPA

Spatial pattern of built-up areas can exert an important influence on surface urban heat islands (SUHIs). While previous studies relied heavily on landscape indicators to characterize land use spatial pattern, such quantitative indicators cannot correspond to distinct spatial positions. By comparison, morphological spatial pattern analysis is an appealing alternative for measuring land use pattern as it can spatially visualize various land use elements from the perspective of mathematical morphology. Therefore, this research moves a step forward in understanding the spatio-temporal connection between the morphological characteristic of built-up areas and SUHI intensity. Taking a largely-urbanized city as an example, we first analyzed the SUHI intensity and morphological characteristic of built-up areas according to multi-temporal remote sensing data. Second, we used the Pearson correlation test and random forest regression to explore the linear and non-linear connections between SUHI intensity and various influence factors, respectively. Compared with landscape pattern, land use morphological characteristic plays a more important role in urban thermal environments. Both the correlation test and random forest regression suggested that the proportion of “core” was a dominant influence factor of the SUHI. The SUHI intensity in the study area was positively connected to the proportions of core, edge, and bridge of built-up areas, but negatively connected to the proportion of islet. Our results can help urban planners emphasize the influence of morphological characteristic in an earlier phase of thermal environment design. This assessment workflow can also be reused for various climatic factors in other cities because of its flexibility.

Effects of water quality on bacterial inactivation by ferrate(VI)

Ferrate (Fe(VI)) is an emerging green oxidant which has great potential and prospect in water disinfection. However, the effects of water quality on Fe(VI) disinfection remain unclear. This study systematically investigated the effects of pH, organic matters and inorganic ions on Fe(VI) inactivation of Escherichia coli (E. coli). Results showed that pH was the dominant influencing factor and the inactivation efficiency as well as inactivation rate constant was negatively correlated with pH (6.8–8.4). HFeO4− was found to be the critical Fe(VI) species contributing to the inactivation. As for organic matters (0–5 mg C/L), protein and humic acid significantly accelerated the decay of Fe(VI) and had negative effects on the inactivation efficiency, while polysaccharide slightly inhibited the inactivation due to the low reactivity with Fe(VI). As for inorganic ions, bicarbonate (0–2 mM) could stabilize Fe(VI) and decreased the inactivation rate constant, while ammonium (0–1 mM) had little effect on the inactivation of E. coli. In addition, the comprehensive effects of water quality on Fe(VI) disinfection in actual reclaimed water were also evaluated. The inactivation of E. coli in secondary effluent and denitrifying effluent was found to be inhibited compared to that in phosphate buffer. Overall, this study is believed to provide valuable information on Fe(VI) disinfection for water and wastewater treatment practices.

A model for solute evolution in laser powder bed fused Al-Si alloys and its application to improve thermal conductivity

A model capable of describing the solute evolution in laser powder bed fused (LPBF) Al-Si alloys has been proposed. The proposed model incorporates the use of three-dimensional Rosenthal equation and a rapid dendrite growth theory. Due to the analytical nature of the equation and the theory, the avoidance of modeling detailed microstructure of cells/dendrites as well as the eutectic, and the neglect of grain nucleation/elimination process, the proposed model is efficient at calculating, taking merely ∼10 min for portraying the spatial distribution of dissolved solute in an entire melt pool. The model was validated by scanning transmission electron microscopic-energy disperse spectrum (STEM-EDS) analysis. The validated model was subsequently applied in designing fabrication strategy of LPBF Al-Si alloys, in hope of improving the alloys’ thermal conductivity through purposefully adjusting processing parameters. This objective was successfully achieved, based on the fact that among imperfections induced by LPBF, dissolved solute atoms are the dominant influencing factor for thermal conductivity, and that the model can reveal the correlations between the overall amount of dissolved solute in the solid solution matrix and laser/feedstock powder parameters.

Polymer Gel for Water Shutoff in Complex Oil and Gas Reservoirs: Mechanisms, Simulation, and Decision-Making

Summary Gel treatment is often used for water shutoff in high water-cut oil or gas wells. Although the properties and usage methods of gel have been well documented by different investigators, gel treatment performance is not always satisfactory in field application, especially in oil or gas reservoirs with complex conditions, such as strong bottomwater reservoirs, high-permeability-ratio oil reservoirs, and fractured gas reservoirs. In this work, we attempt to improve gel treatment application in complex situations according to the causes of disappointing performance, including unreliable numerical simulation and the misapplication of experiences. We propose a new numerical simulation method of gel treatment mechanisms and verify it by improving the acquiring method of inaccessible pore volume (IAPV), dynamic polymer adsorption (DPA), and the simulation method of disproportionate permeability reduction (DPR). The performance and optimization measures of gel treatment in different types of complex oil and gas reservoirs are discussed extensively. Moreover, the dominant influencing factor of the gel treatment effect is determined by gray relation analysis to provide more direct and effective suggestions for field application. The results suggest that the improved access methods for IAPV and DPA can help to obtain more precise parameters easily to construct a numerical gel model. In addition, the new DPR simulation method, which considers oil or gas blocking, reduces the overestimation of gel DPR ability obtained with the conventional method. The misapplication of gel treatment experience probably causes a disappointing response, for example, gel treatment time had opposite influences on water shutoff in strong bottomwater reservoirs and high-permeability-ratio oil reservoirs, and the experience of reservoir thickness in oil reservoirs was not suitable for gas reservoirs. Furthermore, the major factors of gel treatment are varied in different oil and gas reservoirs, demonstrating that primary evaluation indicators for candidate wells are not permanent.

Nanopore structures and controlling factors of the Early Cambrian shale reservoir in the Middle Yangtze Platform, South China

At present, the characteristics and controlling factors of nanopore structure in shale reservoirs are still not well understood owing to the concurrence of both organic matter (OM) and inorganic mineral (IM) pores. This issue is more prominent for the Early Cambrian shale in South China owing to the greatly variable nanopore structures of the samples from different areas. In this study, a set of Early Cambrian shale samples was taken from an exploration well in the Middle Yangtze Platform, a newly-determined shale gas play with a great potential outside the Sichuan Basin, their OM-removed (OMR) samples were obtained by a high-temperature oxidation method, and the pore structures of the bulk shales and their OMR-samples were analyzed by low-pressure gas adsorption experiments. The OM nanopore structure parameters of shale were calculated, and the controlling factors of OM and IM nanopores in the shale were investigated. The results show that the shale nanopores are mainly mesopores, their OM nanopores, especially OM micropores, are obviously more developmental compared with the IM nanopores. The TOC content is the dominant influencing factor of the shale nanopores. The brittle minerals support the formation of interparticle pores, and provide protection to OM pores. The clay minerals provide a certain amount of nanopores, but the strong compaction result in rich micropores. The carbonate minerals decrease the shale nanopores owing to the strong cementation. The favorable area of shale gas in the Early Cambrian strata in the studied area was predicted by the TOC content and preservation conditions.