Resistivity Saturation Research Articles

1-D electrical inversion sensitivity applied to CO2 geological storage monitoring

Discussions on the effects of anthropogenic emissions of greenhouse gas and their consequences on climate change have gained public notoriety in recent decades. The capture of carbon dioxide (CO2) from industrial sources and its subsequent storage in geological reservoirs has the potential to play an important role in reducing the harmful effects of the atmosphere CO2 emissions in the medium and long term. Based on their physical properties for applying geophysical techniques, studying and evaluating the behavior of rocks in the presence of CO2 has shown high relevance. This study deals with monitoring geological reservoirs in the presence of CO2 through the electrical resistivity method to estimate the electrical properties of the rocks involved, such as CO2 saturation and electrical resistivity of the medium. Simulations were performed on a four-layer synthetic model. The results validated the applicability of the electrical method in monitoring CO2 injection and leakage.

IMPACT OF ADVANCED HEMODYNAMIC MONITORING ON MYOCARDIAL REVASCULARIZATION SURGERY IN HIGH-RISK PATIENTS

Coronary artery bypass grafting is a critical procedure for patients with advanced coronary disease, especially those classified as high risk due to comorbidities such as heart failure, hypertension and diabetes. Advanced hemodynamic monitoring has proved essential in this context, allowing continuous and accurate surveillance of cardiac and vascular parameters, which can reduce intra- and post-operative complications. This abstract aims to assess the impact of advanced hemodynamic monitoring during coronary artery bypass graft surgery in high-risk patients. The aim is to explore the advantages of this type of monitoring, the technologies used and the benefits in terms of clinical outcomes and reduction of complications. This is a literature review with a qualitative approach, carried out in the PubMed, SciELO, LILACS, BVS and Google Scholar databases. In order to optimize the search, descriptors such as Hemodynamic Monitoring, Cardiac Surgery, High Risk Patients and Fluid Management were used. For time delimitation, the research considered publications between the years 2019 and 2022, a period that reflects the latest advances in hemodynamic monitoring technologies in high-risk cardiac surgeries. Advanced hemodynamic monitoring includes the use of devices such as the pulmonary artery catheter and non-invasive bioimpedance systems, which provide real-time data on cardiac output, blood pressure, oxygen saturation and systemic vascular resistance. In high-risk patients, these devices allow for precise adjustments in the administration of fluids and vasoactive drugs, promoting better hemodynamic stability. Studies indicate that this approach reduces the incidence of serious complications, such as cardiogenic shock and arrhythmias, optimizing post-operative recovery. Therefore, advanced hemodynamic monitoring is a crucial tool in CABG surgeries, especially for high-risk patients. Its implementation improves intraoperative management, reducing the risk of complications and promoting better clinical outcomes. Therefore, its use should be considered an integral part of strategies for complex cardiac surgeries.

Ca2HfSi4O12:Eu2+: A novel blue phosphor with excellent temperature sensitivity for temperature sensor and cathodoluminescence properties for field-emission displays

A new silicate blue phosphor Ca2HfSi4O12:Eu2+ (CHSO:Eu2+) was designed and synthesized via a solid-state reaction. The structure of CHSO:Eu2+ was analyzed by structure refinement. The electronic structure of CHSO was calculated using first-principles calculations, revealing its effect on luminescence and long-persistent properties. Owing to the O vacancies in the crystal structure, undoped CHSO showed wide blue emission (400–650 nm, λmax = 486 nm) under 296 nm excitation. After being irradiated with a UV lamp for 10 min, the CHSO sample showed obvious afterglow properties that could persist for approximately 50 min above the recognizable intensity level (≥0.32 mcd m−2). CHSO:Eu2+ exhibited excellent temperature sensitivity with a relative sensitivity of 4.5 % K−1@473K, which is higher than those of other Eu2+-based temperature sensor materials. The mechanism between thermal quenching and electronic structure was proposed. Moreover, CHSO:Eu2+ shows excellent cathode ray saturation and aging resistance. This study provides a potential temperature sensor, field-emission-display material, and theoretical reference for developing high-sensitivity temperature-sensing materials.

Estimation of polarity of slope of instantaneous current increment for power swing immune protection of series compensated line

Existing protection schemes for series-compensated transmission line (SCTL) lack either in reliability or speed during power swing (PS). A new ultra-fast reliable method is proposed in the present article using the slope of instantaneous current increment (SICI). The peaks of SICI (denoted by PKS) of a modal component of currents above a dynamic threshold are obtained to detect the sudden jump in SICI, which occurs after a transient disturbance. PKS of two terminal-currents are of same polarity for a fault within SCTL but they are of opposite polarity for any external event. This unique characteristic is mathematically verified and exploited to discern internal faults from external events during PS. Proposed method is found unaffected for high level of series compensation, position of compensation, close-in fault, fault inception point, high fault resistance, synchronization error and CT saturation. The results are finally compared to the incremental quantity-based methods to justify its merit.

An inquiry into transport phenomena and artificial intelligence-based optimization of a novel bio-inspired flow field for proton exchange membrane fuel cells

Achieving an effective flow field configuration is requisite to ensure the optimal performance of a proton exchange membrane fuel cell (PEMFC). Herein, an unprecedented bio-inspired flow field is offered to improve species transport and enhance the power density of PEMFCs in order to provide a pathway for effective utilization of them. The flow field consists of two twin parts, resembling the lung structure, and a repeating converging-diverging pattern, so-called “converging-diverging lung-inspired serpentine (CDLIS).” Utilizing multiphase computational fluid dynamics, this study delves into the transport phenomena and evaluates the comprehensive efficacy of a three-dimensional PEMFC. The CDLIS flow field considerably enhances both crosswise and lengthwise mass transfer by inducing several favorable flow mixing phenomena and improving reactant's velocity distribution. The output power of CDLIS exhibits a substantial increase of 10.87%, 43.63%, 12.22%, 12.83%, 12.52%, and 13.8% compared with the simple serpentine, parallel, two-path serpentine, four-path serpentine, lung-inspired serpentine, and combined parallel-serpentine flow fields, respectively. Due to its highly efficient mass transfer capabilities, enhanced convective mass flow, and outstanding current density, CDLIS possesses the most effective water management and the lowermost flooding risk. To further improve the performance of the PEMFC, artificial intelligence codes based on the non-sorting genetic algorithm II (NSGA II) and a surrogate analytical model are developed to optimize the operating conditions of CDLIS at the limiting current density situation where concentration losses impede the mass transfer of reactants. The target parameters for optimization are current density, water saturation (WS), and oxygen transport resistance (OTR). Under optimum conditions, a remarkable current density of 6.35 A cm−2, a low WS of 0.043, and a reduced OTR of 5.06 s m−1 are obtained.

Interdiffusion mechanism of hybrid interfacial layers for enhanced electrical resistivity and ultralow loss in Fe-based nanocrystalline soft magnetic composites

Soft magnetic composites (SMCs) composed of ferromagnetic particles and insulating binder are highly desired in energy-saving and high-efficiency devices for their high electrical resistivity and softer saturation characteristics. However, traditional insulation coatings are facing thermal instability, inhomogeneous distribution, and magnetic dilution, presenting a major challenge for the trade-off relationship between power loss and permeability. Here, the phosphate-coated FeSiBCuNb/SiO2 SMC is successfully fabricated by a unique interdiffusion effect in hybrid interfacial layers, which shows a combination of ultralow power loss of 135.8 kW/m3 (50 kHz/100 mT), high effective permeability of 80.6, and good temperature stability. The interdiffusion behavior between Si/O and Fe/P/O elements promotes the formation of ultrathin, uniform, and multilayer interface structure, which alleviates the magnetic dilution. Penetrating oxidation at the edge interface and elements interdiffusion effect contribute to a higher electrical resistivity induced by hot isostatic pressing with rapid quenching, leading to a low eddy current loss. Synergistic effect of isostatic pressures and rapid quenching facilitates the formation of high-density Cu clusters corresponding to ultrafine microstructure, which is beneficial for low coercivity and low hysteresis loss. This study involves the interdiffusion mechanism of hybrid interfacial layers and nanocrystalline behavior, providing a new strategy for the next-generation of high-performance SMCs.

RS-AAT for enhancing saturation and chloride resistance in unsaturated concrete: Experimental and numerical assessment

In this paper, the effect of RS-AAT (Reverse-seepage and Saturation based Active Anti-corrosion Technology) on chloride ion erosion and saturation of unsaturated concrete is studied. The design of partially opening of permeable pipes is proposed for partial purpose. The infiltration of chloride ions in cylindrical concrete by RS-AAT is experimentally and numerically analyzed. Based on the water vapor adsorption and adsorption isotherm test and chloride ion erosion test, a convection-diffusion model of chloride ions with varying saturation is established by using simultaneous V-G model and Richards' equation. It can be used for characterizing the effect of pore opening on saturation change and chloride ion erosion. The results show that the use of RS-AAT can accelerate the growth of concrete saturation in the alternating wet and dry zones, and keep the area in a saturated state, under the effect of reverse seepage and saturation, the durability of the structure is increased. Moreover, the opening size and spacing of the permeable pipe are especially investigated. The results recommend 8 mm opening diameter and 2 mm opening spacing, by which the opening spacing is reduced as much as possible, and the ability to resist chloride ion erosion for a long time can be improved s under the combined action of reverse seepage and saturation. The significance of these results is immense for the continued utilization of the novel anti-chloride attack technology in engineering applications.

Examining the Desirable Properties of ZnSnO y by Annealing Treatment with a Real-Time Observation of Resistivity.

In this report, 38 nm-thick amorphous zinc-tin oxide (a-ZTO) films were deposited by radio frequency magnetron cosputtering. a-ZTO films were annealed by in situ monitoring of the sheet resistance improvements during the annealing process. A sharp drop in the slope of the sheet resistance curve was observed. The activation energies for the sheet resistance slope were calculated. The activation energy of the reaction for a sharp drop in the slope is much higher than the activation energy for the rest of the slope. Based on the activation energy values, six annealing temperatures were selected to saturate the highest conductivity at lower annealing temperatures and to identify the effects associated with annealing time. We found a direct correlation between annealing temperatures and the duration of the annealing treatment. a-ZTO films with a high conductivity of 320 S/cm were achieved by annealing at a temperature of 220 °C. It is noteworthy that the annealing temperature of 220 °C has clearly replaced the temperature of 300 °C. An irreversible decrease in resistivity was observed for all films. The conduction mechanism of films before and after annealing was determined. We confirm that all films individually exhibit semiconducting and metallic behaviors in the conduction mechanism before and after the lowest resistivity saturation.

Factors associated with renal oxygen extraction in mechanically ventilated children after the Norwood operation: insights from high fidelity haemodynamic data.

Maintaining the adequacy of systemic oxygen delivery is of utmost importance, particularly in critically ill children. Renal oxygen extraction can be utilised as metric of the balance between systemic oxygen delivery and oxygen consumption. The primary aim of this study was to determine what clinical factors are associated with renal oxygen extraction in children after Norwood procedure. Mechanically ventilated children who underwent Norwood procedure from 1 September, 2022 to 1 March, 2023 were identified as these patients had data collected and stored with high fidelity by the T3 software. Data regarding haemodynamic values, fluid balance, and airway pressure were collected and analysed using Bayesian regression to determine the association of the individual metrics with renal oxygen extraction. A total of 27,270 datapoints were included in the final analyses. The resulting top two models explained had nearly 80% probability of being true and explained over 90% of the variance in renal oxygen extraction. The coefficients for each variable retained in the best were -1.70 for milrinone, -19.05 for epinephrine, 0.129 for mean airway pressure, -0.063 for mean arterial pressure, 0.111 for central venous pressure, 0.093 for arterial saturation, 0.006 for heart rate, -0.025 for respiratory rate, 0.366 for systemic vascular resistance, and -0.032 for systemic blood flow. Increased milrinone, epinephrine, mean arterial pressure, and systemic blood flow were associated with decreased (improved) renal oxygen extraction, while increased mean airway pressure, central venous pressure, arterial saturation, and systemic vascular resistance were associated with increased (worsened) renal oxygen extraction.

The impact of cardiovascular and lung comorbidities in patients with pulmonary arterial hypertension: A systematic review and meta-analysis

BackgroundContemporary patients with pulmonary arterial hypertension (PAH) are older and exhibit cardiovascular and/or lung comorbidities. Such patients have typically been excluded from major PAH drug trials. This systematic review compares baseline characteristics, hemodynamic parameters, and mortality rate between PAH patients with significant number of comorbidities compared to those with fewer or no comorbidities. ΜethodsA systematic literature search in PubMed and Cochrane databases was conducted searching for studies comparing PAH patients with more than two cardiovascular comorbidities and/or at least a lung comorbidity against those with fewer comorbidities. ResultsSeven observational studies were included. PAH patients with comorbidities were older, with an almost equal female-to-male ratio, shorter 6-minute walk distance, higher NT-proBNP levels, and lower lung diffusion for carbon monoxide. In terms of hemodynamics, they had higher mean right atrial pressure and pulmonary artery wedge pressure, lower mean pulmonary arterial pressure, pulmonary vascular resistance and mixed venous oxygen saturation. Pooled analysis of six studies demonstrated a higher mortality risk for PAH patients with comorbidities compared to those without (HR 1.86, 95% CI 1.20 to 2.89, p<0.001, I²=92%), with the subgroup of PAH patients with lung comorbidities having an even higher mortality risk (test for subgroup differences: p<0.001). Combination drug therapy for PAH was less frequently used in patients with comorbidities. ConclusionsCardiovascular and lung comorbidities impact the clinical characteristics and outcomes of PAH patients, highlighting the need for optimal phenotyping and tailored management for this high-risk population.

Numerical investigation of the saturation effect on wick dry-out in a capillary driven evaporative cooling system

The influence of gravity in vertically oriented capillary-driven evaporative cooling systems utilizing porous structures in devices such as heat pipes, vapour chambers and direct wick-based cooling is nontrivial. This can impede the rise of liquid through the structure, diminishing wick saturation. Here we developed a model to quantify the variation of saturation in a vertically oriented porous structure operating at low heat fluxes, with a focus in their use in evaporative cooling of batteries. The model was validated within 15% of the experimental data, and a parametric study was conducted to assess the impact of wick parameters on saturation. Dry-out height and dry-out heat flux were also determined across a range of heat fluxes and wick thicknesses, considering various porosities. Findings indicate that saturation increases with increasing porosity and wick thickness, while decreasing with increasing particle diameter. Furthermore, as porosity and wick thickness increase, the thermal conductive resistance of the wick experiences a substantial increase. Wick porosity has the most significant influence on dry-out height, saturation, and thermal conductive resistance. These insights are valuable for designing capillary-driven evaporative cooling systems operating under gravity.

3D electrical resistivity survey for reduction of groundwater drilling uncertainties in a clay-rich environment

Drilling for groundwater is expensive and challenging. It is even more challenging to find a location that will result in a high-yield well in heterogeneous environments. To tackle the heterogeneity issue, geophysical surveys can help in mapping the subsurface structure and delineating the drilling trajectory. The current study displays the effectiveness of 3D electrical resistivity tomography (ERT) to locate a permeable groundwater zone within a highly heterogeneous and clayey subsurface. Ground truthing the acquired geophysical data with in-situ sampling helps ensure accuracy in classifying groundwater zones in the final inverted 3D data set while also delineating boundaries between permeable groundwater zones and less permeable clayey structures. In-situ samples of groundwater and soil were used to measure the saturated region's resistivity in the laboratory using a column setup. Clay zones in the data set are classified from the nearby well data at similar depth ranges and from very low resistivity values from ERT data and laboratory measurements. The results display highly differentiating resistivity zones that are attributed to the scattered clay lenses (low resistivity) in conjunction with the freshwater zone (high resistivity). The distinction between clayey and nonclayey bodies is important to better inform drilling locations for optimal groundwater yield. This study concludes that with the aid of low-cost geophysical surveys and minimal in-situ sampling data correlations, permeable groundwater boundaries and clay lens volumes can be identified easily.

Application of foam assisted water-alternating-gas flooding and quantification of resistivity and water saturation by experiment and simulation to determine foam propagation in sandstone

Foam flooding by Foam Assisted Water-Alternating-Gas (FAWAG) is an important enhanced oil recovery method that has proven successful in experimental and pilot studies. The present study is carried out to monitor the movement of the foam front once injected into the porous medium. This study aims to investigate applications of resistivity waves to monitor foam propagation in a sandstone formation. In the present lab-scale experiments and simulations, resistivity measurements were carried out to monitor the progression of foam in a sand pack, and the relationships between foam injection time and resistivity, as well as brine saturation, were studied. The brine saturation from foam simulation using CMG STAR is exported to COMSOL and calculated true formation resistivity. A diagram was produced summarizing the progression of foam through the sand pack in the function of time, which enabled us to establish how foam progressed through a porous medium. A surfactant and brine mixture was injected into the sand pack, followed by nitrogen gas to generate the foam in situ. As foam progressed through the sand pack, resistance measurements were taken in three zones of the sand pack. The resistance was then converted into resistivity and finally into brine saturation. As foam travels through the sand pack, it is predicted to displace the brine initially in place. This gradually increases each zone's resistivity (decreases the brine saturation) by displacing the brine. Also, an increase in the surfactant concentration results in higher resistivity. Finally, a comparison of three different surfactant concentrations was evaluated in terms of resistivity results, water saturation, and foam propagation monitoring to obtain the optimum surfactant concentration involved in foam flooding.

Evaluation of Saturation Interpretation Methods for Ultra-Low Permeability Argillaceous Sandstone Gas Reservoirs: A Case Study of the Huangliu Formation in the Dongfang Area

Ultra-low permeability argillaceous sandstone reservoirs have become a significant focus for exploration and development. Saturation is a crucial parameter in evaluating such reservoirs. Due to the low porosity, low permeability, complex pore structure, and strong heterogeneity in ultra-low permeability argillaceous sandstone reservoirs, traditional evaluation methods are unable to achieve the required level of interpretation accuracy. To improve the accuracy of gas saturation calculations in ultra-low permeability argillaceous sandstone gas reservoirs, the conductivity characteristics of the ultra-low permeability argillaceous sandstone gas reservoirs in the Huangliu Formation in the Dongfang area, China, were analyzed through rock physics experimental data and geological information. The results revealed the clay content in the study area to range from 6% to 33.4%. Influenced by burial depth and temperature, kaolinite and montmorillonite transform into illite and chlorite, and the cation exchange capacity is not correlated with the clay content. This suggests that the effects of cation-attached conductivity can be ignored. The regional variation in rock electrical parameters is significant. When the lithology coefficient is a = 1, the consolidation index m varies between 1.25 and 1.75. When the lithology coefficient is b = 1, the saturation index n varies between 1.6 and 1.96. Under the influence of high temperature and pressure, the reservoirs in the study area exhibit two distinct characteristics on the capillary pressure curve, fractal dimension, and effective porosity index intersection diagram, (1) In Class I reservoirs, there is a strong correlation between the formation factor and natural gamma, as well as porosity, and a logarithmic relationship between the saturation exponent and the formation factor; and (2) in Class II reservoirs, there is a strong power-law relationship between the formation factor and porosity, as well as a logarithmic relationship between the saturation exponent and formation factor. Based on experimental and logging data, reservoir classification was conducted using core-scale logging and principal component analysis. Additionally, a saturation interpretation model was developed using multivariate regression, based on rock electrical parameters. The actual application results demonstrate that compared to the fixed rock resistivity saturation model, this model has reduced the average absolute error by 5.9%. The calculated values are consistent with the gas saturation analysis of the core at the pure gas section as determined by cable testing sampling. This model meets the requirements of practical production. The study of this interpretation method is of great significance for the formulation of development plans for ultra-low permeability offshore argillaceous sandstone gas reservoirs.

A Delicate Balance Between Spin-Wave Mediated Weak Localization and Electron-Phonon Scattering in the Design of Zero Temperature Coefficient of Resistivity.

Zero thermal coefficients of resistivity (ZTCR) materials exhibit minimal changes in resistance with temperature variations, making them essential in modern advanced technologies. The current ZTCR materials, which are based on the resistivity saturation effect of heavy metals, tend to function at elevated temperatures because the mean free path approaches the lower limit of the semiclassical Boltzmann theory when the temperature is sufficiently high. ZTCR materials working at low-temperatures are difficult to achieve due to electron-phonon scattering, which results in increased resistivity according to Bloch's theory. In this work, the ZTCR behavior at low-temperatures is realized in pre-microstrained Mn3NiN. The delicate balance between the resistivity contribution from electron-phonon scattering and spin-wave mediated weak localization is well revealed. A remarkable temperature coefficient of resistivity (TCR) value as low as 1.9ppmK-1 (50K≤T≤200K) is obtained, which is significantly superior to the threshold value of ZTCR behavior and the application standard of commercial ZTCR materials. The demonstration provides a unique paradigm in the design of ZTCR materials through the contraction effects of two opposite conductance mechanisms with positive and negative thermal coefficients of resistivity.

First Real-Life Data on the Diving Response in Healthy Children.

Swimming and diving are popular recreational activities, representing an effective option in maintaining and improving cardiovascular fitness in healthy people. To date, only little is known about the cardiovascular adaption to submersion in children. This study was conducted to improve an understanding thereof. We used a stepwise apnea protocol with apnea at rest, apnea with facial immersion, and at last apnea during whole body submersion. Continuous measurement of heart rate, oxygen saturation, and peripheral resistance index was done. Physiologic data and analysis of influencing factors on heart rate, oxygen saturation, and peripheral vascular tone response are reported. The current study presents the first data of physiologic diving response in children. Data showed that facial or whole body submersion leads to a major drop in heart rate, and increase of peripheral resistance, while the oxygen saturation seems to be unaffected by static apnea in most children, with apnea times of up to 75s without change in oxygen saturation.

The Impact of Driving Pressure-Guided Positive End-Expiratory Pressure Ventilation on Cerebral Blood Flow and Pulmonary Function in Patients Undergoing Laparoscopic Radical Prostatectomy.

To examine the impact of driving pressure-guided positive end-expiratory pressure ventilation on cerebral blood flow and pulmonary function in patients undergoing laparoscopic radical prostatectomy. A retrospective analysis was conducted on clinical data from patients who underwent laparoscopic radical prostatectomy at our hospital between June 2022 and June 2023. The patients were divided into two groups, namely the conventional ventilation group and the driving pressure-guided positive end-expiratory pressure ventilation group. Measurements and analyses were performed on cerebral blood flow, neurological status, and pulmonary function parameters. A total of 105 patients were included in this single-centre retrospective study, with 51 patients in the conventional ventilation group and 54 patients in the driving pressure-guided positive end-expiratory pressure ventilation group. The driving pressure-guided positive end-expiratory pressure ventilation group demonstrated significantly higher cerebral blood flow, cerebral autoregulation index, cerebrovascular resistance, and cerebral oxygen saturation compared to the conventional ventilation group (p < 0.05). Additionally, patients in the driving pressure-guided positive end-expiratory pressure ventilation group exhibited improved neurological outcomes, a higher partial pressure of oxygen/fraction of inspired oxygen ratio, increased lung compliance, decreased peak expiratory flow, elevated respiratory rate, and a lower lung injury score compared to the conventional ventilation group (p < 0.05). The findings suggest that driving pressure-guided positive end-expiratory pressure ventilation might positively influence cerebral blood flow and pulmonary function parameters in patients undergoing laparoscopic radical prostatectomy.

Effect of heterogenous dopant and high temperature pulse excitation on ozone sensing behavior of In2O3 nanostructures and an image recognition method coupled to ozone sensing array

Ground-level ozone (O3) is a primary air pollutant with potential adverse impacts on human health and ecosystems. Aiming to detect O3 concentration and develop efficient O3 sensing materials, sensing behavior of heterogenous cation (Fe3+, Sn4+ and Sb5+) doped In2O3 nanostructures was investigated. The incorporation of these cations modulated the electronic structure of semiconductor oxides, affecting the density of chemisorbed oxygen species and reactive sites. From O3 sensing results, Fe3+ doped In2O3 based sensors featuring saturated resistance curves in O3 gas, demonstrated fast sensing speed and qualified detection threshold (20 ppb). In contrast, Sn4+ and Sb5+ doped counterparts exhibited non-saturated sensing curves, resulting in slower response/recovery speed. As a proof-of-concept, these optimized sensors were integrated as the sensor array. Coupled to the image recognition technique, this sensor array could successfully discriminate O3 and NOx. That is, through the tailored combination of material modulation and sensor array, this study paves a novel approach for highly sensitive and selective O3 detection.

Petrophysical and Geomechanical Analysis to Delineating Reservoirs in the Miocene Niger Delta Region of Nigeria

The application of various petrophysical and elastic metrics has advanced reservoir characterization and provided critical geological formation information. Porosity declines with depth, according to sonic, neutron, and density logs. Lithology, pressure, and hydrocarbons all contribute to this. Formation resistivity and fluid saturation are used to identify hydrocarbon-bearing zones. Because oil and gas are non-conductive, hydrocarbon-containing rocks are more resistant than water. In lithological categorization, gamma logs and the Vp/Vs ratio have helped classify reservoirs as Agbada Formation sand-shale reservoirs. Reservoir elastic characteristics, specifically sandstones, have been studied at various depths. These discoveries have an impact on their brittleness, strength, and failure risk in a variety of scenarios. Hydrocarbon accumulation has been influenced by diagenetic compaction equilibrium in pressure-exposed shale source beds. The research advances our understanding of the geological formations of the Niger Delta and gives practical insights for exploration and production. Decisions on oil and gas are based on hydrocarbon reservoir assessments at various depths, including porosity, fluid saturation, and lithology. Well logs from Wells B001, B002, and B003 revealed the diverse properties of several Niger Delta reservoirs. These discoveries have benefited hydrocarbon exploration and production decision-making significantly.

Mechanical analysis of eight-legged temporary support structure under wave forces.

This paper presents a mechanical analysis of the foundation of a temporary offshore platform using a temporary embedded eight-leg support structure. The model is simulated using the finite element simulation software MIDAS-3D, with the modified RANS equation and Forchheimer saturated resistance model used to control the fluid. The stress analysis principle of the structure is simplified by the pile group theory. The stability of the eight-legged supporting structure is investigated under different embedding depths, pile diameters, wave periods, and amplitudes of the main piles. The results show that the eight-legged supporting structure can intercept and divert water flow, eliminating the impact of the water flow on the main piles during large waves. Additionally, as the diameter of the structure increases under the same wave conditions, the influence of the base volume and surface curvature gradually increases, deteriorating the stress environment of the main pile and decreasing the supporting effect of the eight-legged support structure. Numerical calculations of the seabed rock foundation of the eight-leg supporting structure show that the shallow pile foundation undergoes significant deformation, while the eight-leg supporting structure is still supported by the dead weight of the main pile.