Average Saturation Research Articles

Reservoir Potential Evaluation of the Middle Paleocene Lockhart Limestone of the Kohat Basin, Pakistan: Petrophysical Analyses

The Lockhart Limestone is evaluated for its reservoir potential by utilizing wireline logs of Shakardara-01well from Kohat Basin, Pakistan. The analyses showed 28.03% average volume of shale (Vsh), 25.57% average neutron porosity (NPHI), 3.31% average effective porosity (PHIE), 76% average water saturation (Sw), and 24.10% average hydrocarbon saturation (Sh) of the Lockhart Limestone in Shakardara-01 well. Based on variation in petrophysical character, the reservoir units of the Lockhart Limestone are divided into three zones i.e., zone-1, zone-2 and zone-3. Out of these zones, zone-1 and zone-2 possess a poor reservoir potential for hydrocarbons as reflected by very low effective porosity (1.40 and 2.02% respectively) and hydrocarbon saturation (15 and 5.20%), while zone-3 has a moderate reservoir potential due to its moderate effective porosity (6.50%) and hydrocarbon saturation (52%) respectively. Overall, the average effective porosity of 3.31% and hydrocarbon saturation of 24.10% as well as 28.03% volume of shale indicated poor reservoir potential of the Lockhart Limestone. Lithologically, this formation is dominated by limestone and shale interbeds in the Shakardara-01 well. Cross-plots of the petrophysical parameters versus depth showed that the Lockhart Limestone is a poor to tight reservoir in Shakardara-01 well and can hardly produce hydrocarbons under conventional drilling conditions.

Ecogeographical Characterization of Passiflora cincinnata Mast. and Passiflora setacea DC. Native to the Central-Southern Mesoregion of Bahia

Passiflora cincinnata and Passiflora setacea are two native species from the northeastern semiarid region, with wide distribution in the central-southern mesoregion of the Bahia state. These species are recognized for the production of bioflavonoids. However, although they have economic relevance, little is known about ecogeographic, morphological and ecophysiological aspects. Therefore, the goal was to characterize the physiochemical and granulometric attributes of the soil as well as the edaphoclimatic conditions in 12 locations of naturally occurring Passiflora cincinnata and Passiflora setacea in the central-southern mesoregion of Bahia. The results showed environments belonging to the ecotones of the Cerrado, Caatinga and Mata Atlântica biomes. In these phytophysiognomies, the soils varied between cambisol, oxisol and planosol and presented a sandy texture and acidic pH. They also have varied ecogeographic characteristics with altitudes between 481 and 929 meters, precipitation between 478 and 1.644 millimeters and average temperature ranging between 15 and 31 degrees. Sites with average temperatures of up to 28 degrees, altitude between 670 and 860 meters, pH between 4.3 and 5.11, base saturation smaller than 50 and H+Al between 2-5 favor both species. Temperatures up to 31 degrees, pH between 5 and 6, base saturation bigger than 50 and H+Al smaller equal 1.5 favor P. cincinnata. Environments with temperatures of up to 27 degrees, altitudes above 900 meters, average pH of 4.5, average base saturation of 30 and average H+Al of 3, favors P. setacea. Keywords: environmental adaptation; ecogeography; genetic resources; wild passion fruit; sleep passion fruit.

Novel elastomeric spiropyran-doped poly(dimethylsiloxane) optical waveguide for UV sensing

Novel poly(dimethylsiloxane) (PDMS) doped with two different spiropyran derivatives (SP) were investigated as potential candidates for the preparation of elastomeric waveguides with UV-dependent optical properties. First, free-standing films were prepared and evaluated with respect to their photochromic response to UV irradiation. Kinetics, reversibility as well as photofatigue and refractive index of the SP-doped PDMS samples were assessed. Second, SP-doped PDMS waveguides were fabricated and tested as UV sensors by monitoring changes in the transmitted optical power of a visible laser (633 nm). UV sensing was successfully demonstrated by doping PDMS using one spiropyran derivative whose propagation loss was measured as 1.04 dB/cm at 633 nm, and sensitivity estimated at 115% change in transmitted optical power per unit change in UV dose. The decay and recovery time constants were measured at 42 and 107 s, respectively, with an average UV saturation dose of 0.4 J/cm2. The prepared waveguides exhibited a reversible and consistent response even under bending. The sensor parameters can be tailored by varying the waveguide length up to 21 cm, and are affected by white light and temperatures up to 70 ℃. This work is relevant to elastomeric optics, smart optical materials, and polymer optical waveguide sensors.Graphical

Geological and Hydrochemical Processes Driving Karst Development in Southeastern Riyadh, Central Saudi Arabia

This study investigates the processes leading to karst development in the southeastern part of Riyadh city extending up to Al Kharj. Numerous solution features such as sinkholes, collapsed dolines, and solution caverns are common in the area. The role of water in the development of the karst features was investigated using an integrated geological and hydrochemical approach. Geological investigations included the petrographic analysis of rock samples collected from zones of intense karstification with special emphasis on mineral dissolution. The study showed that the Sulaiy Formation is commonly fractured, brecciated, foliated, and contains numerous cavities, vugs, and openings. These features have formed by mineral dissolution by circulating groundwater, which has removed anhydrite beds from the underlying Arab–Hith sequence. Karstification likely started from the tectonically weak zones when there was more groundwater recharge. Studies show that during the early to mid-Holocene period, the climate in the Arabian Peninsula was humid, promoting groundwater recharge and subsequent mineral dissolution, though the process of karstification must have started much earlier. Hydrochemical findings reveal that mineral dissolution (halite and calcium sulfate) is the main process affecting groundwater chemistry. The Piper plot revealed two main hydrochemical facies: the (Ca2+ + Mg2+)–(Cl+ SO42−) Type (Type A) and the (Na+ + K+)–(SO42− + Cl) Type (Type B). Most of the samples belong to Type B, typical of groundwater facies affected by dissolution of halite and anhydrite mineral. The absence of the (Ca2+ + Mg2+)–(CO32− + HCO3−) type of groundwater facies indicates a lack of recent groundwater recharge and the removal of carbonate minerals from the system through precipitation, as evidenced by the saturation indices. Plots of the major ionic pairs (cations vs. anions) in groundwater indicate strong halite and gypsum/anhydrite dissolution. Of the three carbonate minerals, calcite has the highest average saturation index followed by aragonite and dolomite. This suggests significant past rock–water interaction leading to carbonate dissolution. Presently, any additional calcium or carbonate ions introduced into the water lead to calcite precipitation. The study indicates that the process of karst development may not be active today. Currently, groundwater chemistry is mainly influenced by rock–water interaction leading to gypsum/anhydrite dissolution, which has resulted in a high concentration of Na+, Ca2+, Cl− and SO42− ions in groundwater. The dissolution of gypsum and halite from the Hith Formation weakens the structural integrity of the overlying Sulaiy Formation, creating large underground cavities. These cavities increase the risk of roof collapse, leading to cover-collapse sinkholes as the roof becomes too thin to support the weight above.

DEVELOPMENT OF AN ALGORITHM FOR CALCULATING COMPONENT COMPOSITION TO IMPROVE THE DEVELOPMENT OF OFFSHORE OIL FIELDS IN THE NORTH CASPIAN BASIN

The paper presents an algorithm to reconstruct the component composition of the mixture based on the results of production modeling in the black oil format and a fixed set of tables with the results of phase equilibrium calculations in a given pressure range. The approach is based on analyzing the ratio of flow rates for each phase and the ratio between average reservoir pressure and saturation pressure. The algorithm takes into account the possibility of oil degassing when saturation pressure decreases, as well as gas breakthrough of gas caps to the bottoms of producing wells.Implementation of the method is based on a unified thermodynamic model of multilayer reservoir, built on the principles of a single set of HC mixture components and uniform parameters of the equation of state on a set of fluid samples for all modeling stages: reservoir model, model of the gathering system and site facilities. In addition to steady-state flow calculations performed together with reservoir modeling, the unified model is planned to be used for dynamic flow calculations in the corresponding simulator (well start/stop), which will allow solving production problems in the process of operation of wells with complex completions.The conversion algorithm is automated using modern high-level tools: Python and data automation components from MS Excel, which eliminates the need for manual data input at all stages and makes it possible to obtain the estimated component composition of produced fluid for any set of wells and for any time step within the forecasting horizon.The obtained compositions are used to verify the reproduction of the main controlled parameters (oil density and gas oil ratio) and can be used for subsequent calculations of fluid transportation and treatment systems.The implemented algorithm has been tested for stability at different ratios of gas and oil flow rates by wells and meets the practical requirements of engineering calculations — the error of oil density is not higher than 2 % and gas factor is not higher than 10 %.

PSYCHOPATHOLOGY OF EMOTIONAL SPHERE IN PATIENTS WITH CHRONIC CEREBRAL ISCHEMIA AND OBSTRUCTIVE SLEEP APNEA

Obstructive sleep apnea (OSA) is the most common sleep disorder globally. OSA affects 2–6 % of the adult population and 15–26 % of those aged over 70. The main daytime OSA symptoms are daytime sleepiness, decreased mood and concentration. Patients with chronic cerebral ischemia (CCI) often have the same complaints. Although such symptoms characterize emotional and affective disorders, the patients are usually treated by neurologists. The purpose of the study is to identify the characteristics of emotional and affective disorders in patients with chronic cerebral ischemia and obstructive sleep apnea. Materials and Methods. The study involved 45 patients aged 50–78 with CCI, type 1–2. Patients were examined for OSA and underwent cardiorespiratory monitoring. The psychoemotional status of individuals with CCI and OSA was assessed according to HADS, SHAPS, and ESS. Statistical analysis of cardiorespiratory monitoring parameters determined the critical level of average night saturation, at which depressive symptoms are detected. Results. It was found that patients with severe OSA had more severe depressive symptoms and anhedonia, but lower anxiety levels compared with CCI patients without severe OSA. The authors determined critical levels of mean night saturation for development of depression (SpO2avrg<89 %) and clinically significant depression (SpO2avg<87 %). Conclusion. Depression is proved to be the most common emotional disorder in patients with CCI and concomitant OSA. The authors determined critical levels of average night saturation for depressive disorders in patients with CCI type 1–2.

Analysis of Natural Gas Hydrate Resource Content based on Kriging Algorithm and TOPSIS Evaluation Model

The exploration and evaluation system for natural gas hydrate resources is currently incomplete. Research on evaluation methods for the quantity of natural gas hydrate resources is an important part of theoretical studies and is crucial in guiding exploration and development activities. In this paper, we establish the total effective thickness (Z), average porosity of the reservoir ( ), and the absolute value of average saturation ( ) as indicators for evaluating the quantity of natural gas hydrate resources. We then statistically analyze the data from various exploration points to obtain the values of these indicators. Subsequently, we employ the Kriging algorithm to interpolate the data, obtaining a more densely distributed grid. Following this, we establish a TOPSIS evaluation model to calculate the scores of each exploration point. Finally, a heat map is generated to represent the distribution of resource quantity scores in various regions. The results indicate that natural gas hydrate resources are primarily distributed in the upper left, lower right, and directly below the detection area.

Investigation of gas residuals in sandstone formations via X-ray core-flooding experiments: Implication for subsurface hydrogen storage

The production and utilization of hydrogen (H2) as a clean energy source offer a promising solution towards achieving net-zero carbon emissions. Utilizing sandstone formations for geological hydrogen storage presents a viable option for the practical implementation of the hydrogen economy, offering both safe and large-scale containment capabilities. Accurate assessment of gas displacement behavior in porous media plays a critical role in understanding gas saturation, gas residual, and long-term storage duration. However, there are limited studies available on dynamic displacements for hydrogen storage applications. This study aims to enhance the understanding of gas flow behavior in sandstone rocks for different gas types and determine the role of capillary pressure and gas wettability during hydrogen storage. A series of gas core-flooding experiments are performed on a brine-saturated sandstone core sample using three different gases (CO2, CH4, and H2). X-ray scanning technique is applied to detect the gas saturation and gas residual after the core-flooding experiments. The results indicate that the average gas saturation ranges between 25 and 40%, with zero gas residual for all gases, suggesting that the gas residuals in this clean sandstone sample are unaffected by the gas type. Initially, the capillary pressure profile for the sample displayed low brine saturation at 200 psi, indicating very low capillary pressure in the sample due to the high permeability and large pore radius, despite the strong water-wetting behavior of the sample. Moreover, the obtained results indicate the high potential for gas recovery (especially for hydrogen during withdrawal cycles), and the high displacement efficiency in sandstone rocks. The reported low gas residual suggests that the wettability of the rock is not affected by gas injection, and it appears that the wettability and capillary pressure are not the controlling factors for gas storage in this sandstone sample. This observation suggests that the structural trapping mechanism is most likely to be the dominant trapping mechanism in this shallow high permeable sandstone rock. Also, the injection of cushion gases such as CO2 and CH4 indicated similar results to hydrogen injection, due to the low capillary pressure and high permeability in this sandstone sample. The findings of this study can greatly enhance the understanding of gas injection, displacement behavior, and gas residuals in sandstone rocks related to underground hydrogen storage.

Growth of high quality polycrystalline InGaO thin films by spray pyrolysis for coplanar thin-film transistors on polyimide substrate

The current mobile devices are moving towards flexible electronics. Introducing crystalline oxide semiconductors on flexible substrates is important to satisfy the requirements of high-resolution displays on flexible substrates. This study investigates the low-cost, as-grown polycrystalline (Poly) InGaO thin film transistor by spray pyrolysis on polyimide (PI) substrate. Grazing Incidence X-ray Diffraction (GI-XRD) measurements demonstrate that In0.8Ga0.2O, In0.7Ga0.3O, and In0.5Ga0.5O compositions exhibit crystallization on-set temperatures of ∼330, ∼350, and ∼415°C, respectively. Poly-In0.7Ga0.3O thin film with lower oxygen-vacancy (∼15 %) and less than 5 % O-H group could be achieved at the substrate temperature of 370°C. The hysteresis-free device performance with an average saturation mobility of 43.73 cm2V−1s−1 has been obtained using the poly-In0.7Ga0.3O with optimized N2O plasma treatment on the poly-oxide thin film. The TFTs show remarkable stability under humid environments and various stress conditions such as positive bias temperature, negative bias temperature, and mechanical stresses. In addition, the 96-stage gate shift register made of poly-In0.7Ga0.3O TFTs by spray pyrolysis exhibits the rising and falling times of less than 820 ns. Therefore, the poly-In0.7Ga0.3O TFTs by spray pyrolysis could be used for high-resolution, cost-effective, flexible active-matrix light-emitting displays.

A novel model for oil reservoirs considering stress sensitivity and dynamic relative permeability

ABSTRACT Stress sensitivity and dynamic relative permeability are undeniable phenomenon in oil reservoir numerical simulation. In this paper, a complex two-phase flow model was established considering the deformation of porous media and relative permeability dynamic changes during water injection. A sensitivity analysis on this new model is carried out. The results reveal that stress sensitivity is a key factor that cannot be ignored when using reservoir numerical simulation to calculate water saturation. When the stress-sensitivity coefficient is not considered, the average water saturation of the model is 51.59%. When the stress-sensitivity coefficient is 0.12MPa−1, the average water saturation of the model is 48.45%. After considering stress sensitivity, the average water saturation of the model decreases by 6.1%. The water saturation difference between the new model and the traditional model is mainly reflected in the vicinity of the water injection well. Additionally, the influence of the range of changes in reservoir permeability on the calculation of water saturation by the new model cannot be ignored.

Differences in Anthropometric, Sleep and Respiratory Characteristics between Hypercapnic and Normocapnic Patients with COPD-OSA Overlap Syndrome.

Overlap syndrome (OS), the coexistence of chronic obstructive pulmonary disease and obstructive sleep apnea, is frequently characterized by the presence of daytime hypercapnia (pCO2 ≥ 45 mmHg). The aim of this study was to investigate potential differences in anthropometric, sleep and respiratory characteristics between hypercapnic and normocapnic patients with OS. Consecutive patients who underwent polysomnography, pulmonary function testing and arterial blood gases and had been diagnosed with OS were enrolled in the study. According to pCO2 levels in wakefulness, the patients were divided into group A, consisting of OS patients without hypercapnia (n = 108) or group B, consisting of OS patients with hypercapnia (n = 55). The majority of included patients in both groups were males (n = 92 in group A vs. n = 50 in group B). Group B had increased BMI (p = 0.001), neck (p = 0.017) and waist circumference (p = 0.013), higher scores in Epworth sleepiness scale (ESS) (p = 0.008), increased sleep efficiency (p = 0.033), oxygen desaturation index (p = 0.004) and time with oxyhemoglobin saturation <90% (p = 0.006) than group A. Also, Group B had decreased average and minimum oxyhemoglobin saturation during sleep (p < 0.001). Hypercapnic patients had lower FEV1% (p = 0.003), FVC% (p = 0.004), pO2 and pCO2 (p < 0.001 for both) values compared with normocapnic patients. In binary regression analysis, which assessed various predictors on the likelihood of having hypercapnia, it was found that BMI (OR: 1.313, 95% CI: 1.048-1.646, p = 0.018) and FVC (OR: 0.913, 95% CI: 0.845-0.986, p = 0.020) were the major determinants of hypercapnia in OS patients. Hypercapnic OS patients were more obese and sleepy and presented worse respiratory function in wakefulness and sleep hypoxia characteristics compared with normocapnic OS patients.

Study on displacement units for water flooded low-permeability oil reservoirs

Understanding the reservoir feature changes is essential for optimizing oil exploitation throughout the development lifecycle. This paper proposed an analytical displacement unit method to character the features of water-flooded, low-permeability oil reservoirs. The method hinges the ratio of fluid flux to area and average water saturation, providing a fine description of reservoir dynamics. It has been implemented in a case study of a five-spot waterflooding scheme. The reservoir can be categorized into sixteen distinct unit types, each with specific attributes. This paper delves into the evolution of these displacement units and the key factors that influence their behavior. The findings provide insights into the degree of waterflooding and oil distribution following continuous waterflooding. Furthermore, the proposed method offers a valuable framework for analyzing the development of dominant water flow channels and exploiting the residual oil.

Integrated Analysis of the Eocene Sakesar Formation: Depositional Environment, Microfacies, Geochemistry, and Reservoir Characteristics in the Potwar Basin, Pakistan

The current study aimed to evaluate the petroleum generation potential of the Sakesar Formation. This study interprets and presents a depositional environment model, microfacies, and geochemical and petrophysical data of the Eocene Sakesar Formation in the Potwar Basin, Pakistan. Twenty well-cutting samples from two wells and six fresh outcrop samples were thoroughly studied. Results of total organic carbon and Rock-Eval pyrolysis of Sakesar Formation sediments show fair to good TOC contents ranging from 1.2-1.67 wt%. S2 values of samples showed fair to good generation potential. Sediments appear mature, having primarily mixed Type II-III kerogen with good oil/gas-generation potential. Three microfacies have been identified in the Sakesar Formation at the Tatral section: Bioclastic wacke-packstone, Lockhartia-rich mud-wackestone, and benthic foraminiferal wackestone. The microfacies of the Sakesar Limestone depict the deposition of the Sakesar Limestone from the distal middle ramp to restricted inner ramp settings. Petrophysical well logs analysis of the Sakesar Formation showed an average porosity of ~9.12%; the lithology was identified as limestone, having an average water saturation of ~22.32% and an average hydrocarbon saturation of ~77.68%. Thus indicating average to good reservoir properties with very good hydrocarbon saturation. Sakesar Formation sediments characteristics interpretation showed that it can act as both source rock and reservoir rock in the Potwar Basin.

Comprehensive risk assessment and interactions of fluoride and boron ions in the water-sediments interface: The Red Sea, Egypt

This study presents a baseline evaluation of the distribution, human and ecotoxicological risk, and the potential interactions of fluoride and boron in the water-sediment interface in 25 locations from incredible Red Sea tourist destinations. Results showed comparable levels of B and F in the water and sediments with previous literature. Significant positive correlation was found between B and F (r = 0.57; P<0.01). Based on the sediment/liquid partition coefficient (Kd), F is more likely to be released from the sediment into seawater (logKd< 3) than B (3<logKd< 4). pH and alkalinity may affect water-sediment interactions of B and F, respectively, while SO42− and Cl− ions had no significant effect on adsorption ability of F and B. The majority of minerals had average saturation Index (SI) > 1 referring to the over saturation of seawater with these minerals and their inability to dissolve. The formation of CF, FAP, and CFAP may be related to the high correlation between Fw (r = 0.928, P< 0.01; r = 0.527, P< 0.01; r = 0.608, P< 0.01) and Bw (r = 0.38, P< 0.05; r = 0.38, P< 0.05; r = 0.397, P< 0.05). Total hazard quotient (THQ) for children and adults were <1, revealing no health risks from exposure to B and F through ingestion and skin contact while swimming. The risk characterization ratio; RCRmix(MEC/PNEC) showed high short-term risks to aquatic organisms. Further investigations might emphasis on emerging mitigation strategies to address these concerns.

The study of the relationship between moderate to severe sleep obstructive apnea and cognitive impairment, anxiety, and depression.

The present study endeavored to investigate the interconnection between obstructive sleep apnea (OSA) and cognitive function, alongside the manifestations of depression and anxiety. Simultaneously, an analysis was conducted to discern the factors exerting influence upon cognitive function. A cohort of 102 patients, who had undergone polysomnography (PSG) at Binhu Hospital, Anhui Medical University, between January 2022 and June 2023, was encompassed in the study. Employing the PSG findings, these individuals were classified into two distinct categories: the grouping consisted of those with either negligible or mild OSA, and the other comprised individuals with moderate to severe OSA. Utilizing the Montreal Cognitive Assessment (MoCA-Beijing), Stroop Color and Word Test (SCWT), Digit Span Test (DST), Self-rating Depression Scale (SDS), and Self-rating Anxiety Scale (SAS), scores were recorded and analysed for each of the respective assessments. Additionally, discrepancies and associations between these groups were also scrutinized. The group exhibiting moderate to severe OSA demonstrated significantly elevated measurements in parameters such as neck circumference, BMI, completion times for SCWT-A, B, C, Sleep Inefficiency Index (SIE), SAS, and SDS, in comparison to the No or Mild OSA group. Furthermore, the moderate-severe OSA group manifested notably diminished MoCA scores in areas of visual-spatial and executive function, memory, language, abstraction, delayed recall, orientation, total MoCA score, lowest oxygen saturation (LSaO2), average oxygen saturation, Digit Span Test-backward(DST-b), and Digit Span Test-forward(DST-f), as contrasted with the no-mild OSA group. These inter-group disparities exhibited statistical significance (p < 0.05). The MoCA total score portrayed inverse correlations with age, Apnea-Hypopnea Index (AHI), BMI, SIE, SAS, SDS, CT90%, AHT90%, and Hypoxic Apnea Duration (HAD) (ranging from -0.380 to -0.481, p < 0.05). Conversely, it displayed positive correlations with DST-f, DST-b, LSaO2, and average oxygen saturation (ranging from 0.414 to 0.744, p < 0.05). Neck circumference, AHI, and SAS were autonomously linked to MoCA scores (OR = 1.401, 1.028, 1.070, p < 0.05), while AHI exhibited an independent correlation with SDS and SAS scores (OR = 1.001, p = 0.003). Patients grappling with moderate to severe OSA frequently reveal cognitive impairment and concomitant emotional predicaments encompassing depression and anxiety. These manifestations share an intimate association with AHI, LSaO2, and average oxygen saturation. Notably, anxiety, when coupled with OSA, emerges as an autonomous influential element impinging upon cognitive impairment.

Development and validation of a novel sleep health score in the sleep heart health study

BackgroundThere is a lack of consensus in evaluating multidimensional sleep health, especially concerning its implication for mortality. A validated multidimensional sleep health score is the foundation of effective interventions. MethodsWe obtained data from 5706 participants in the Sleep Heart Health Study. First, random forest-recursive feature elimination algorithm was used to select potential predictive variables. Second, a sleep composite score was developed based on the regression coefficients from a Cox proportional hazards model evaluating the associations between selected sleep-related variables and mortality. Last, we validated the score by constructing Cox proportional hazards models to assess its association with mortality. ResultsThe mean age of participants was 63.2 years old, and 47.6% (2715/5706) were male. Six sleep variables, including average oxygen saturation (%), spindle density (C3), sleep efficiency (%), spindle density (C4), percentage of fast spindles (%) and percentage of rapid eye movement (%) were selected to construct this multidimensional sleep health score. The average sleep composite score in participants was 6.8 of 22 (lower is better). Participants with a one-point increase in sleep composite score had an 10% higher risk of death (hazard ratio = 1.10, 95% confidence interval: 1.08–1.12). ConclusionsThis study constructed and validated a novel multidimensional sleep health score to better predict death based on sleep, with significant associations between sleep composite score and all-cause mortality. Integrating questionnaire information and sleep microstructures, our sleep composite score is more appropriately applied for mortality risk stratification.

High quality a-InGaZnO and a-ZrAlO deposited at 375 °C by spray pyrolysis for low voltage operation TFTs

We report the high-performance, bottom-gate a-InGaZnO (IGZO) TFT with high-k ZrAlO (ZAO) gate insulator by spray pyrolysis (SP). The a-IGZO/ZAO TFT exhibits the average saturation mobility of 23.12 cm2 V−1 s−1, subthreshold swing of 121 mV dec-1, ION/OFFratio of ∼108 with no hysteresis and low off-state current of ∼10-19A µm−1. In addition, the TFT exhibits good interface quality with less trap density (∼9x1010 cm−2) and conduction band tail state (∼4.3x1018 cm−3) extracted from TCAD fitting. The high-performance is attributed to the formation of uniform and dense a-IGZO and ZAO thin films with low defect density. Therefore, the SP a-IGZO/ZAO TFTs have great potential to be employed in low-cost, low driving voltage TFTs for display application.

Flow Characterization in Fractured Shale Oil Matrices Using Advanced Nuclear Magnetic Resonance Techniques

The evaluation of flow dynamics in fractured shale oil reservoirs presents significant challenges due to the complex pore configurations and high organic material concentration. Conventional methods for petrophysical and fluid dynamic evaluations are insufficient in addressing these complexities. However, nuclear magnetic resonance (NMR) technology is an effective technique for quantitatively delineating fluid micro-transport properties across the reservoir core. This study presents an experimental methodology rooted in NMR technology to quantify the flow capabilities within the shale oil matrix. This approach incorporates high-pressure saturation flow experiments across seven distinct core samples to gauge the micro-transport phenomena of fluids across various pore dimensions. The results revealed that under high-pressure saturation, shale cores devoid of fractures demonstrated an average crude oil saturation rate of merely 19.44%. Cores with evident stratification exhibited a 16.18% increase in flow capacity compared to their non-stratified counterparts. The flow dynamics within these shale reservoirs exhibited a range of behaviors, from non-linear to linear. In lower-permeability zones, non-linear patterns became increasingly apparent. An NMR T2 spectrum analysis was used to identify the minimum effective pore size conducive to shale oil flow within the matrix, which was between 8 and 10 nanometers. These insights provide a foundation for a deeper understanding of the mechanisms behind oil and gas migration in fractured shale oil matrices, offering valuable insight into their extractive potential.

Integrated petrophysical, sedimentological and well-log study of the Mangahewa Formation, Taranaki Basin, New Zealand

This study aims to address the problem of porosity preservation in the Mangahewa Formation of five main hydrocarbon fields covering onshore and offshore of the Taranaki Basin. An integrated reservoir characterization of the Middle to Late Eocene Mangahewa Formation is achieved through petrophysical evaluation, sedimentological and petrographical descriptions, and well log analysis methods. Petrophysical parameters (porosity and permeability) were acquired from the available core analysis and using mathematical equations to obtain other petrophysical matrices such as normalized porosity index (NPI) and reservoir quality index (RQI). Factors that affected Mangahewa reservoir were studied through thin-section microscopy and well-log analysis helped to measure the reservoir and hydrocarbon potentiality in the Mangahewa Formation. The Mangahewa Formation is dominated by sandstone and a range of marginal to shallow marine facies with varying hydraulic flow units (HFU). The Mangahewa Formation has a high positive correlation in porosity-permeability relationship and has a maximum of 4.67 μm RQI and 20.08 μm FZI (Well Kapuni-14) which reflect potential reservoir. The Mangahewa Formation observed from Wells Kapuni-14, Maui-A1G, McKee-16A, and Mokau-1 are dominated with 59.6%, 56.4%, 79.3%, and 68% of macro- and megapores, respectively. The presence of authigenic clay and calcite cement has greatly reduced the reservoir quality; however, primary and secondary pores are still observed within the Mangahewa sands. Moreover, well log analysis was carried out on four wells in Taranaki Basin, to run a qualitative and quantitative analysis of the Mangahewa reservoir. Eight potential reservoir zones were examined, revealing that the Mangahewa Formation has a very low shale volume of less than 6%, good effective porosity ranging between 11.0% and 13.3%, up to 36.2% of average water saturation and maximum of 69.8% average hydrocarbon saturation. In conclusion, from this comprehensive study, it can be deduced that the Mangahewa Formation possesses fair to good reservoir quality and hydrocarbon potentiality.

The Influence of Arctic Conditions on the Formation of Algae and Cyanobacteria Diversity and on the Water Quality of Freshwater Habitats on Kotelny Island, Lena Delta Wildlife Reserve, Yakutia

The significant interest in the islands in the Russian Arctic has been in terms of available oil reserves, which determine the direction of economic development and associated environmental risks for this sector of the Arctic in the near future. Kotelny Island is the largest island of the New Siberian Islands Archipelago included in the protected zone of the Lena Delta Nature Reserve, which is located at 76° N, washed from the west by the Laptev Sea, washed from the east by the East Siberian Sea in a permafrost zone, and characterized by harsh climatic conditions defined by the northeast winds that prevail in vegetative season. January sees temperatures ranging from −32 to −35 °C, and July from +6 to +8 °C, which causes a short growing season. Samples were taken between August 3 and 8, 2018 in 12 freshwater bodies where 210 taxa were revealed. Aquatic communities were dominated by zygnematophycean and diatom algae, grouped in the basins of two rivers and associated with the position on the island’s landscape, which suggests the influence of cold north-east winds, leading to the avoidance of habitats in open and high places, which was revealed by statistical methods and also confirms the high individuality of taxa composition. Bioindication methods showed that water bodies are slightly alkaline, with low ion concentrations, with the presence of sulfides in low-lying habitats, and average saturation with organic matter. The mesotrophic status of the studied water bodies was evaluated through an assessment and the type of nutrition in the communities of algae and cyanobacteria indicates they formed there as true autotrophs, which corresponds to the status of a protected area and can serve as a reference level for monitoring anthropogenic impact.