Application of polymeric nanofluids for enhanced oil recovery in mid-permeability sandstone

Enhanced Oil Recovery (EOR) processes are used to recover bypassed and residual oil trapped in a reservoir after primary and secondary recovery methods. Recently, polymeric nanofluid, a novel material formed from the incorporation of polymer and nanoparticle has gained prodigious attention and is proposed for EOR due to its sterling and fascinating properties. Nonetheless, previous studies have focussed more on the suitability of inorganic silica and non-metallic polymeric nanofluids (PNFs). Besides, the performance evaluation of PNFs on pore scale displacement efficiency remains obscure while the mechanistic understanding of this novel material for heavy oil recovery in typical reservoir conditions is elusive in literature. The aim of this study is to explore and exploit the effect of nanoparticles on rheological properties of partially hydrolysed polyacrylamide (HPAM) at varying electrolyte concentration and temperature conditions. Besides, IFT and wettability alteration potential of the PNFs in the presence of heavy oil were evaluated. Herein, two PNFs namely silicon dioxide (SiO2) and aluminium oxide (AhOs), formulated from the combination of the individual nanoparticles and HPAM were exclusively studied. The nanoparticles were characterised using transmission electron microscopy, while the formulated PNFs were characterised using Fourier transform infrared microscopy and thermo gravimetric analysis to determine the morphology and thermal stability respectively. The rheological properties of the PNFs and HPAM were determined using Brookfield RST. Furthermore, the behaviour of the PNFs and HPAM at oil-water interface was investigated using Kruss tensiometer. Moreover, the wettability effect of the fluids in sandstone cores was examined using DataPhysics optical contact angle equipment. Finally, heavy oil displacement in mid-permeability sandstone cores at typical reservoir condition was carried out using HPHT core flooding equipment. Experimental results show that the rheological properties improved while degradation of HPAM molecules was inhibited due to the addition of NPs. At 2,000 ppm HPAM solution (27 mol % hydrolysis degree), 0.1 wt.% NP concentration was found to be the optimal choice for AhO3 and SiO2 NP which gives rise to the highest viscosity on the rheological characterization. PNFs exhibited better steady shear viscosity performance under the different electrolyte concentration and temperature studied due to shielding effects. Besides, PNFs lowers IFT of heavy oil due to irreversible adsorption of the NP’s at the oil-water interface. Moreover, PNF’s alter wettability of sandstone cores from oil-wet to water-wet due to structural disjoining pressure mechanism. Field emission scanning electron microscope and energy-dispersive x-ray analysis confirm adsorption of nanoparticles on the sandstone cores. Finally, heavy oil displacement test in midpermeability sandstone cores showed that incremental oil recoveries of AhO3 and SiO2 PNFs at their optimum concentration were 10.6% and 6.1% respectively over HPAM. Physical filtration phenomena lowered the efficiency of the PNF’s at higher concentrations. The synergic combination of NPs and polymer resulted in enhanced properties of HPAM, hence, culminating in enhanced sweep and pore scale displacement efficiencies. This study is beneficial for extending the frontiers of knowledge in nanotechnology application for EOR

EXPLOITATION OF BITUMEN FROM NIGERIAN TAR SAND USING HOTWATER/ STEAM STIMULATION PROCESS

With the upward surge in global demand for energy, unconventional energy resources are being considered as options to quell the growing energy demand. These unconventional energy resources like oil sand, shale oil, shale gas, tight gas, are fast becoming alternatives to complement the conven-tional energy resources. Tar sand exploitation is being commercialized globally. With success stories from Canada, Venezuela and U.S.A., other countries tend to follow. Nigerian tar sands, which is similar to Canada’s tar sand in terms of chemical composition, water wet nature, etc., has some characteristics which will yield enormous economic benefit when exploited. The possibility of producing heavy oil from the Nigerian tar sand deposits by steam stimulation was evaluated in this paper with respect to the technology (Cyclic Steam Stimulation), environmental impact and the economic analysis, with Canada’s success stories used as reference point. The result of the study showed that heavy oil could be produced with steam stimulation process with little impact on the environment and with huge economic potentials

A COMPARISON OF THE EFFECTS OF PREPARATION VARIABLES ON ACTIVITY OF COMPOSITE ANTHILL-CHICKEN EGGSHELL CATALYST FOR BIODIESEL PRODUCTION

This study is initiated to develop a composite catalyst from naturally occurring and waste materials. The catalyst preparation conditions which include activation temperature (600-1000 o C), activation time (2-4 h) and mixing proportion of anthill to eggshell (1:1.5-1:4) were investigated using central composite design (CCD) of response surface methodology (RSM) in design expert software. A model that correlates the three process parameters to the response (biodiesel yield) was established. The model reliability was evaluated using analysis of variance (ANOVA). The catalyst prepared under the optimum conditions was characterized using scanning electron microscopy (SEM), Fourier transform infrared radiation (FTIR) spectroscopy and X-ray Diffraction (XRD) technique. From the ANOVA, both the predicted and experimental biodiesel yields agreed well with each other with correlation coefficient (R 2) of 0.9806. The optimum composite anthill-eggshell catalyst preparation conditions were obtained as follow, activation temperature of 1000 o C, 4 h activation time and anthill/ eggshell mixing ratio of 1:4, which provided biodiesel yield of 70.92

E XPLOITATION OF B ITUMEN FROM N IGERIAN T AR S AND U SING H OT -W ATER /S TEAM S TIMULA - TION P ROCESS

With the upward surge in global demand for energy, unconventional energy resources are being considered as options to quell the growing energy demand. These unconventional energy resources like oil sand, shale oil, shale gas, tight gas, are fast becoming a lternatives to complement the conven - tional energy resources. Tar sand exploitation is being commercialized globally. With success stories from Canada, Venezuela and U.S.A., other countries tend to follow. Nigerian tar sands, which is similar to Canada’s t ar sand in terms of chemical composition, water wet nature, etc., has some characteristics which will yield enormous economic benefit when exploited. The possibility of producing heavy oil from the Nigerian tar sand deposits by steam stimulation was evalua ted in this paper with respect to the technology (Cyclic Steam Stimulation), environmental impact and the economic analysis, with Canada’s success stories used as reference point. The result of the study showed that heavy oil could be produced with steam stimulation process with little impact on the environment and with huge economic potential

Polymer nanocomposites application in drilling fluids: A review

Indubitably, drilling fluid is the most crucial component of drilling operations. With the current exploration of hydrocarbons in deep water horizons, unconventional formations, and anticipated production from the arctic regions, there is a need to improve the properties of existing drilling fluids for harsh conditions. Recently, the synergic combination of polymer and nanoparticle (polymer nanocomposite) has gained prodigious attention for application as a drilling fluid additive due to its sterling and fascinating properties. Herein, the application of polymer nanocomposite (PNC) as an additive in drilling fluids has been reviewed. The survey of the literature shows that PNC significantly improved the rheological, filtration, and shale swelling inhibition properties of drilling fluids. Nonetheless, accurate modelling of its behaviour remains elusive. The mechanism of the improved efficiency of PNC as a drilling fluid additive was elucidated. Finally, the gaps in the research were highlighted, and recommendations for future studies were outlined. Overall, drilling fluids containing PNC exhibited comparably higher efficiency and immense potential to overcome severe wellbore problems encountered with conventional drilling fluids

Rheological and filtration control performance of water-based drilling muds at different temperatures and salt contaminants using surfactant-assisted novel nanohydroxyapatite

Today, the high-performance rheological and filtration properties of nanosized particles (NPs) in water-based muds (WBMs) are continuously reported. Nevertheless, NP's properties performance at different temperatures and salt environments, specifically the salt-screening process, needs additional knowledge. Hence, this study developed a WBM system using sodium dodecyl sulfate (SDS)-assisted nanohydroxyapatite (Nano-HAp) for different temperatures and salt contaminants. The impacts of the newly-produced Nano-HAp on the density, pH, rheology, and filtration characteristics of WBM at 298 K and 353 K were examined. The effects of salt cations (Ca2+/Na+) on a bentonite-based suspension (BN-WBM) at 298 K and 393 K and SDS-aided Nano-HAp as a salt-tolerant ingredient in drilling muds were also examined. The Herschel-Buckley and Power law models best described SDS-aided Nano-HAp drilling mud's rheology at 298 K and 353 K, respectively. Nano-HAp improved the rheological and filtration capabilities in salt and water solutions at 298 K, 353 K, and 393 K, making it a perfect field additive. 1.0 g of SDS-aided Nano-HAp is recommended, and it is thermally very stable, according to the thermal gravimetric analysis findings. It increased the viscosity performance by 78.6% at 298 K and by 79.2% at 353 K, provided desirable shear stress between 1.0 and 1000 s−1 shear rates, and decreased the fluid loss by 31.8% (≤ 8 mL) at 298 K and 25% (≤ 11 mL) at 353 K. In BN-WBM, it decreased the viscosity of the BN-salt solution from a 35-fold increase to less than a 5-fold increase and made the BN-based suspension less salt-reliant. It operated by attaching to the BN platelets' positive edge and negative face surfaces, shielding Ca2+/Na+ cations from the BN's ion-susceptible regions to decrease the viscosity and filtration of the BN-based suspension. This study demonstrates the possible use of Nano-HAp particles as effective filtration and rheological control additives in WBMs. It further demonstrates that Nano-HAp was appropriate for enhancing the drilling performance of BN-WBMs while increasing their resistance to salt cation contamination

Global burden of 288 causes of death and life expectancy decomposition in 204 countries and territories and 811 subnational locations, 1990–2021: a systematic analysis for the Global Burden of Disease Study 2021

BACKGROUND Regular, detailed reporting on population health by underlying cause of death is fundamental for public health decision making. Cause-specific estimates of mortality and the subsequent effects on life expectancy worldwide are valuable metrics to gauge progress in reducing mortality rates. These estimates are particularly important following large-scale mortality spikes, such as the COVID-19 pandemic. When systematically analysed, mortality rates and life expectancy allow comparisons of the consequences of causes of death globally and over time, providing a nuanced understanding of the effect of these causes on global populations. METHODS The Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2021 cause-of-death analysis estimated mortality and years of life lost (YLLs) from 288 causes of death by age-sex-location-year in 204 countries and territories and 811 subnational locations for each year from 1990 until 2021. The analysis used 56 604 data sources, including data from vital registration and verbal autopsy as well as surveys, censuses, surveillance systems, and cancer registries, among others. As with previous GBD rounds, cause-specific death rates for most causes were estimated using the Cause of Death Ensemble model-a modelling tool developed for GBD to assess the out-of-sample predictive validity of different statistical models and covariate permutations and combine those results to produce cause-specific mortality estimates-with alternative strategies adapted to model causes with insufficient data, substantial changes in reporting over the study period, or unusual epidemiology. YLLs were computed as the product of the number of deaths for each cause-age-sex-location-year and the standard life expectancy at each age. As part of the modelling process, uncertainty intervals (UIs) were generated using the 2·5th and 97·5th percentiles from a 1000-draw distribution for each metric. We decomposed life expectancy by cause of death, location, and year to show cause-specific effects on life expectancy from 1990 to 2021. We also used the coefficient of variation and the fraction of population affected by 90% of deaths to highlight concentrations of mortality. Findings are reported in counts and age-standardised rates. Methodological improvements for cause-of-death estimates in GBD 2021 include the expansion of under-5-years age group to include four new age groups, enhanced methods to account for stochastic variation of sparse data, and the inclusion of COVID-19 and other pandemic-related mortality-which includes excess mortality associated with the pandemic, excluding COVID-19, lower respiratory infections, measles, malaria, and pertussis. For this analysis, 199 new country-years of vital registration cause-of-death data, 5 country-years of surveillance data, 21 country-years of verbal autopsy data, and 94 country-years of other data types were added to those used in previous GBD rounds. FINDINGS The leading causes of age-standardised deaths globally were the same in 2019 as they were in 1990; in descending order, these were, ischaemic heart disease, stroke, chronic obstructive pulmonary disease, and lower respiratory infections. In 2021, however, COVID-19 replaced stroke as the second-leading age-standardised cause of death, with 94·0 deaths (95% UI 89·2-100·0) per 100 000 population. The COVID-19 pandemic shifted the rankings of the leading five causes, lowering stroke to the third-leading and chronic obstructive pulmonary disease to the fourth-leading position. In 2021, the highest age-standardised death rates from COVID-19 occurred in sub-Saharan Africa (271·0 deaths [250·1-290·7] per 100 000 population) and Latin America and the Caribbean (195·4 deaths [182·1-211·4] per 100 000 population). The lowest age-standardised death rates from COVID-19 were in the high-income super-region (48·1 deaths [47·4-48·8] per 100 000 population) and southeast Asia, east Asia, and Oceania (23·2 deaths [16·3-37·2] per 100 000 population). Globally, life expectancy steadily improved between 1990 and 2019 for 18 of the 22 investigated causes. Decomposition of global and regional life expectancy showed the positive effect that reductions in deaths from enteric infections, lower respiratory infections, stroke, and neonatal deaths, among others have contributed to improved survival over the study period. However, a net reduction of 1·6 years occurred in global life expectancy between 2019 and 2021, primarily due to increased death rates from COVID-19 and other pandemic-related mortality. Life expectancy was highly variable between super-regions over the study period, with southeast Asia, east Asia, and Oceania gaining 8·3 years (6·7-9·9) overall, while having the smallest reduction in life expectancy due to COVID-19 (0·4 years). The largest reduction in life expectancy due to COVID-19 occurred in Latin America and the Caribbean (3·6 years). Additionally, 53 of the 288 causes of death were highly concentrated in locations with less than 50% of the global population as of 2021, and these causes of death became progressively more concentrated since 1990, when only 44 causes showed this pattern. The concentration phenomenon is discussed heuristically with respect to enteric and lower respiratory infections, malaria, HIV/AIDS, neonatal disorders, tuberculosis, and measles. INTERPRETATION Long-standing gains in life expectancy and reductions in many of the leading causes of death have been disrupted by the COVID-19 pandemic, the adverse effects of which were spread unevenly among populations. Despite the pandemic, there has been continued progress in combatting several notable causes of death, leading to improved global life expectancy over the study period. Each of the seven GBD super-regions showed an overall improvement from 1990 and 2021, obscuring the negative effect in the years of the pandemic. Additionally, our findings regarding regional variation in causes of death driving increases in life expectancy hold clear policy utility. Analyses of shifting mortality trends reveal that several causes, once widespread globally, are now increasingly concentrated geographically. These changes in mortality concentration, alongside further investigation of changing risks, interventions, and relevant policy, present an important opportunity to deepen our understanding of mortality-reduction strategies. Examining patterns in mortality concentration might reveal areas where successful public health interventions have been implemented. Translating these successes to locations where certain causes of death remain entrenched can inform policies that work to improve life expectancy for people everywhere. FUNDING Bill & Melinda Gates Foundation

Experimental investigation of magnetized-Cocos nucifera husk supported Citrullus lanatus peel microparticles as loss circulation agent in water-based drilling fluids

Lost circulation agents (LCAs) are usually added to drilling fluids (DFs) for fluid loss control into formation. This improves their filtration and rheological properties that are advantageous for well drilling operation. This study conducted experimental investigation of Cocos nucifera husk (CNH) and Citrullus lanatus peel (CLP) as fluid loss additive in water-based drilling fluids (WB-DFs). The effect of magnetizing 50 and 100 μm CNH and CLP microparticles (MPs) on the effectiveness of WB-DFs was investigated. Prototype core samples of uniform dimension were prepared from unconsolidated sandstone. The rheological, filtration, and petrophysical properties of samples were evaluated. Scanning electron microscope (SEM) and Fourier transform infrared spectrophotometer (FTIR) were used to characterize drilling fluid samples. Plastic viscosity (PV), gel strength (GS), yield point (YP), mud cake thickness (MCT), and mud density (MD) of magnetized CNH supported CLP microparticles in WB-DF (mMp-CNH-CLP-WB-DF) increased by 44.44%, 14.29%, 60.71%, 16.08%, and 26.64%, respectively, when the weight was increased from 5 g to 20 g. The filtrate volume (FV) reduced by 56.38% when the weight of CNH and CLP was increased from 5 g to 20 g. The drilling fluid was less alkaline at this condition. The formation damage (FD) percentage of mMp-CNH-CLP-WB-DF decreased from 12.57% to 7.31% at 100 psi and 100 µm particle size. SEM and FTIR showed smooth particle arrangement and presence of active functional groups. In conclusion, presence of mMp-CNH-CLP-WB-DF in WB-DF improved its suitability for use in drilling operation