bluuebunny/crossref_metadata_2025 huggingface dataset:
Efficient and Comprehensive Integrity Diagnostics for Dual Completion String Wells, Using Spectral Noise Analyzer Tool
Authors: Baharum Zurailey Bin , Rourke Marvin , Muhadjir Alan Aulia , Andono Widyanto , Zakaria Eva Sarah Binti , Hamzah Suzie Binti , Hademi Noor Rohaellizza Binti , Hamdan Nurul Aida Binti
Published: December 2021

Well operators often face various technical challenges when intervening and repairing older, mature field wells. The most common problem associated with aging wells are tubing and casing integrity. Uncertain sources of downhole leaks and data ambiguity often lead to incorrect diagnostics that can hinder repair work or even contribute to additional or worsened integrity issues. Operators continuously challenge service companies and technology providers to drive innovation. One such challenge is in finding efficient and comprehensive integrity diagnostics for dual-string wells.

A basic and general diagnostic method to verify well integrity in dual-string wells involves setting plugs in the long and short strings and pressure testing the tubings. These operations are generally time consuming, and the test data does not usually pinpoint the location of the leak, if any. Since 2016 a new diagnostic solution for this challenge has been implemented using a slickline-deployed passive acoustic logging technique. Carefully designed intervention planning, combined with efficient data acquisition, led to significant time saving and improved data quality.

A more complete assessment of the integrity of both strings is now more frequent and often necessary, while challenging the conventional thinking of having to assess the lower string only while assuming the upper string is in good condition. However, investigating dual-string integrity with uncertainty on the source of leak, restrictions on facilities and limitations on surveillance time will often waste more time and money if not approached carefully.

This paper discusses two case studies, including a dual-string oil producer in the South China Sea that had sustained pressure in production casing annulus. The well operator initially considered that the long string had an integrity issue, while the short string did not, based on their surface-based annulus pressure diagnostics. Consequently, the operator decided to diagnose only the long string. The passive acoustic memory tool. combined with a fast-response temperature and spinner used for the diagnosis, identified a possible short string leak while logging through the long string. This result clearly demonstrated that surface analyses can be misleading, and a comprehensive downhole diagnostic should be the recommended method to identify leaks, especially in dual-string completions.

This well operator has completed more than 100 integrity diagnostic runs in the last five years. The passive acoustic diagnostic interventions have resulted in an average 50-percent time saving compared to legacy methods, and data analysis results have led to significant improvements in well productivity.
Outcrop Analogues to Fractured Reservoirs, UAE
Authors: Noufal Abdelwahab
Published: December 2021

Fractures were not the focus of reservoir studies in Abu Dhabi for the last decades, although its importance in enhancing production, as the general understanding considering fractures are not contributing to production. The fractured carbonate outcrops provide useful analogue observations, data and concepts to support subsurface hydrocarbon reservoir characterization from well and seismic data. The fracture orientation, size, porosity, length, spacing, crosscutting relationships, fracture density versus lithology and bed thickness and connectivity are difficult to measure directly from subsurface well and core data. The understanding of fracture formation and distribution and their effects on fluid flow has been greatly improved by the use of outcrop analogue data through the current work.

This paper address the fracture geometry, kinematics and mechanical properties based on outcrops matching Abu Dhabi subsurface reservoir analogues. Integrating outcrop data with fracture orientation and fracture density from core and borehole image data, and seismic capturing fractures characteristics. The outcrop analogues constrain the uncertainty and developing new concepts in characterizing the interplay of rock matrix and fracture networks relevant to fluid flow and hydrocarbon recovery. Analysing the fractures with fracture lengths, aperture, spacing per each interval and relate them to the tectonic event are extracted strictly in the reservoir section.

The results showing developed highly dipping shear fractures with short length, small spacing and bimodal aperture distribution that related to fracture orientation. Fracture porosity is dependent on size and controlled by lithology, bed thickness, paleostress and rock composition.

Understanding fractures and their behaviour will optimize production greatly and they create exploration targets in otherwise tight reservoir zones, including under-explored sections.
Adding Extra Dimensions for Completion Consideration: Case Studies with Geoengineering, Measurement While Pumping, and Data Mining
Authors: Liu Yuan , Mu Lijun , Zhao Zhengfeng , Li Xianwen , Enkababian Philippe
Published: December 2021

Well completion has evolved rapidly in the past two decades, as multistage completion has become the predominant practice to complete a well in many places. Although innovation in completion tool technology has been continuous in recent years, there are still gaps in the well completion optimization practice. In this paper, we add additional dimensions to well completion technology by incorporating geoengineering, measurement while pumping, and data mining, and we have evidence to show that those additional elements help to improve our understanding, on-site efficiency, and overall performance.

Multistage completion optimization is about where and how to complete a well. Different methods were employed in the past, and even with a better-engineered completion design where both reservoir and completion quality are honored, there are still area for improvement. For example, 1) geological properties are not qualitatively utilized in the completion design; 2) real-time operational feedback during the execution phase is inadequate for in-time decisions for completion and fracturing adjustment; 3) the completion-to-well-performance cycle is so long that the learning curve is not fast enough, and too many influential factors are hidden in the details.

Three extra dimensions were added to address the improvement areas. Geoengineering adds "space information" in enabling geological properties from a 3D space grid to be projected onto the wellbore as geology quality (GQ) so that the information can be used together with reservoir and completion quality (RQ and CQ) quantitatively to improve the fracturing treatment design. Measurement while pumping (MWP) adds "timely feedback" in that real-time operational feedback—either from the wellbore via high-frequency pressure monitoring or from the target zones via microseismic data in offset horizontal monitoring wells—can help with the completion and fracture diagnosis and decision making on-site. Data mining adds "pattern recognition" in that reservoir and operation data are collected and analyzed to generate a systematic understanding of the reservoir complexity, paving the way for the improved planning of future well completions in the same region. Each of the solutions comes with specific case studies in our work.

Geoengineering, MWP, and data mining add three dimensions to the current well completion practice. In our case studies, these approaches have demonstrated the capability to improve the accuracy of the design, increase confidence in the execution, and accelerate the learning curve from evaluation. The extra dimensions added to the current completion practice are essentially space, time, and pattern, and together, they help to define the direction of future innovations for completion optimization.
Bioremediation of Cutting Pits by Autochtonous Bacteria-Fungi Consortia
Authors: Carpani Giovanna , Pietrini Ilaria , Baric Massimiliano , D'Ambrosi Francesca , Cova Carlo Alberto , Akhtar Jahanzaib , Buffagni Melania
Published: December 2021

The aim of this work is to verify the potential of a consortium of autochthonous bacteria and fungi, isolated from samples of contaminated soils and water collected in a site containing cutting pits muds, in order to evaluate enhancing in biodegradation of hydrocarbons content. This innovative technique would take advantage of the synergistic effect of bacteria and fungi. In addition, this technique would allow to avoid the introduction of commercial allochthonous microflora for soil remediation and the use of chemical products for tool cleaning.

Samples retrieved from a production site were used to isolate bacterial and unicellular fungal species able to grow on hydrocarbons were demonstrated to be able to degrade light and "diesel-like" hydrocarbons under laboratory conditions and in liquid cultures in less than a month. The activity of the consortium was also tested on crude oil, showing an overall degradation of the analyzable fraction greater of sixty percent after a 14-day incubation. Low C number linear hydrocarbons were the preferred substrate, but also cycloalkanes and mono- and di-aromatics seemed to be a good growth substrate. Probably, the action of enzymes secreted by fungal strains could enhance the degradation of complex molecules such as polycyclic aromatic hydrocarbons.

Lab tests of consortium efficiency on mud samples are ongoing and an on-site pilot test is foreseen, to prove the activity of the consortium under the challenging field conditions. The development of fungal and bacterial consortia for degradation of complex hydrocarbon mixtures will represent an innovative approach that combines the action of enzymes secreted by fungi followed by the bacterial breakdown, a synergistic effect which could potentially increase the rate and effectiveness of hydrocarbons decontamination.
Impact of Fit-for-Purpose Monitoring on EOR Planning
Authors: Moreno Jaime Eduardo , Liu Yunlong , Talabi Oluwale , Gurpinar Omer , Kristensen Morten , Goh Gordon Kim Fah , Paydayesh Mehdi
Published: December 2021

Challenges in the design of efficient EOR field pilots have been discussed and documented in the industry, particularly when it comes to optimization of monitoring plans for technical and economical perspectives. This paper explores the benefits of pilot planning where the monitoring/control strategies are included in the early stages of the design to reduce risk of measurements ambiguity and ensure good quality pilot results evaluation. It addresses the use of new and existing technology in monitoring by highlighting the advantages and challenges of each alternative including potential pairing of complementary options to achieve the pilot objectives including illustration of the use of continuous and sporadic measurements on the evaluation.

The proposed approach starts with a review of reservoir performance, heterogeneity and pilot objectives to ascertain the plausible monitoring technologies/strategies to aid during the pilot de-risking, followed by the identification of adequate novel and mature monitoring options, which are specific to EOR type and measurement nature (permanent, time lapse, etc.). Advantages of incorporating the monitoring strategy as integral part of the pilot design, as well as evaluation of the effectiveness/viability in the presence of uncertainty of the selected monitoring alternatives are discussed providing a reference of suitable/plausible EOR specific technologies. The paper illustrates the importance of selecting monitoring alternatives that feed off each other and the importance of using fit-for-purpose evaluation algorithms and a digitally enabled, structured approach to analyze and democratize pilot results and enable actionable decisions in operations.
Lessons Learnt Reprocessing a Noisy Onshore 3D Seismic Survey
Authors: Holt Rob , Al Darmaki Fatima , Gonzalez Jose Rodriguez , Anderson Paul F , Adiletta Steve
Published: December 2021

An 1,100 km2 400-fold seismic survey was acquired over some of the largest sand dunes in UAE in 2007. Large sand dunes generate many challenges for seismic processing due to the irregular data acquisition, large statics caused by the significant difference between the sand and sabkha velocities, and a massive amount of reverberation noise that hides the signal in the data.

Occidental and ADNOC Sour Gas reprocessed this survey from January 2019 to August 2020 to overcome the challenges of the strong sand dune noise. For the first time, it was processed through prestack depth migration (PSDM). The primary objectives of the reprocessing project were to get an accurate PSDM volume that tied all of the available well control data; and to derive as accurate seismic amplitudes as possible over the target reservoir interval from near to far offsets to enable elastic inversion for reservoir porosity and net-thickness prediction.

Whilst the reprocessing project achieved the project objectives and generated good subsurface images, it did not run as smoothly as hoped, despite being processed by one of the premier multinational processing companies. The extremely large sand dunes, which are present across most of the survey area, created major imaging problems. Key technical lessons learnt during reprocessing included: (1) CRS errors occurred sporadically during acquisition, requiring correction; (2) the sand curve (Liner, 2008) worked well for sand dune static corrections for this data set; (3) near surface statics changed whilst the survey was acquired by up to 6 ms - each shot station needed to be corrected for these statics changes because the shot stations were acquired twice with a symmetric split recording spread; and (4) the contractor's standard post-migration processing sequence (gather flattening, radon, noise attenuation, stack) did not work well for this very noisy data set. Next time we work with similar data and require a high quality result, we know to double the estimated project timeline as every step in the processing sequence takes much longer than expected when the signal-to-noise ratio of the data is very low.

The novelty of this work was that we obtained large improvements in the seismic stack by applying offline gather conditioning before calculating trim statics to optimally flatten the very noisy migrated offset vector tile (OVT) gathers, prior to running the final noise attenuation and stacking workflows. Without this offline gather conditioning, the trim statics workflow mostly aligned the noise and damaged the stack.
Total Systems Approach to Reduce Fouling and Improve System Efficiency Using Hydrogen Sulfide Scavengers
Authors: McRae James Alexander , Marais Willem-Louis , Jenkins Alyn
Published: December 2021

The Cotton Valley sand and Haynesville shale formations are situated in East Texas, USA, producing oil, gas, and condensate on land. Most of the producing assets are mature and souring, and the presence of hydrogen sulfide in the produced fluids and gas provides both operational concerns in terms of solids deposition and asset integrity in the production facilities as well as complexity when considering the processing, export, and sale of condensate and gas.

Produced gas was traditionally treated with MEA triazine hydrogen sulfide scavenger prior to liquification by LNG plant. There have been historical issues with both the levels of hydrogen sulfide left in the gas and also solids formation in the process, which threatened periodic shutdown of the LNG plant. A holistic approach was used to improve the overall sulfur removal process. This includes the reduction or elimination of solids formation as well as improvement in the system scavenging efficiency. The approach considered current operating procedures, system parameters, equipment design (contactors), and H2S scavenger chemistry.
Gamification in Training of Holistic Multidisciplinary Petroleum Asset Management
Authors: Aslanyan Arthur , Popov Arkady , Asmandiyarov Rustem , Margarit Andrey
Published: December 2021

The paper shares a 4-years’ experience of "Gazprom Neft" PJSC on Digital Twin Learning Program in training of holistic multidisciplinary petroleum asset management and engineering based on the on-line cloud PetroCup software facility.

The objective of the program was to train and test large amounts of managers and engineers with minimum off-work time and motivate self-improvement among the employee.

The program includes warm-up videos, immersive master-classes, training courses, discussion clubs and Annual Corporate Championship, with a strong focus on home learning, remote communication, simulation-based exercises and automated testing/certification.

The program is divided into Master Development Planning (MDP) and Well & Reservoir Management (WRM) domains which are related to different stages of the petroleum asset lifecycle.

The interaction with simulator takes 2-3 days for WRM and 5 days for MDP and engages a multidisciplinary team: asset manager, economist, contract engineer, surface facility engineer, reservoir engineer, geologist, petrophysicist, simulation engineer, well test engineer, well and log analyst and production technologist.

The session starts by reading the existing field data and its history and then perform well drilling, completions, workovers, well tests, open-hole and cased-hole logging, manage production and injection targets, build/modify the surface production/injection facilities and receive the fully automated asset response in the form of the field reports, very much in the same way as in real life.

Once session is over the simulator generates a detailed debriefing report on team performance in numerous areas: economical, production, injection, reservoir and well performance so that team can understand where it did a good job and where it was not efficient.

The current paper shows how this facility has been integrated into the corporate staff capability program, expanded to anchor universities and shed the light to the future perspectives.
A Success Story of Critical Data Gathering During the Development Phase of Extreme ERD Well Drilling
Authors: Anurag Atul Kumar , Alkatheeri Adel , Sainz Alvaro , Javid Khalid , Liu Yaxin , Al-Ali Ahmed , Telang Viraj Nitin , Indulkar Kshudiram , Kieduppatum Piyanuch , Thar Hiten Pankajkumar
Published: December 2021

This paper discusses a holistic combination of advanced formation evaluation techniques with pressure testing and reservoir navigation services to mitigate uncertainty related challenges in real time and successfully drill & place ERD laterals targeting Jurassic carbonate reservoirs. A meticulously planned approach to navigate the well trajectory by tracking the desired properties, informed decision-making while drilling and accurate data acquisition for aiding appropriate selection and placement in-flow control device (ICD) in lower completion design and future reservoir management contributed to the success of these complex wells in carbonate reservoirs.

The first well in this study, involved drilling and evaluating a long lateral section as single oil producer targeting a carbonate reservoir. While no tar presence was expected, a combination of density, neutron porosity and nuclear magnetic resonance (NMR) logs while drilling resulted in identifying a deficit NMR porosity when compared to density porosity. Deployment of a formation pressure testing while drilling (FPWD) tool enabled measurement of the formation mobility and validate the presence of a tar. Using the same combination of measurements in the subsequent wells for delineating the tar enabled accurate planning of injection wells on the periphery of the field.

Approximately 3 days were saved compared to the first well where the drill string had to be POOH to run-in with FPWD service. Hence, having FPWD tool in the same string helped in confirming the formation mobility in real time to call for critical decision making like changing the well trajectory or calling an early TD. Across all the wells drilled in this field, the formation pressure, mobility and porosity measurements provided valuable input for optimum ICD placement and design. Successful identification of unexpected tar resulted in substantial rig time savings, accurate planning of asset utilization and added confidence in design and placement of lower completions by utilizing LWD data. Benefits of integrated data and services combination became clear for applications involving advanced reservoir characterization and enhanced well placement in complex carbonate reservoirs.

From the offset wells, a tar was seen in deeper formations but the integration of LWD NMR and mobility data from this well confirmed the presence of a tar within the zone of interest. The study established a cost-effective workflow for mitigating uncertainties related to tar encountered while drilling extreme ERD laterals in an offshore environment where any lost time results in significant increase in expenditures during the development phase. A systematic approach to tackle these uncertainties along with acquisition of critical data for the design & placement of completion results in optimum production from the reserves.
Well Integrity Catastrophe Avoided Through Advanced Well Integrity and Reservoir Monitoring Analysis, a Case Study
Authors: Elyas Mohamed , Aly Sherif , Achinanya Uche , Prosvirkin Sergey , AlSaffar Shayma , Mohammad Muthafar , Siddiqui Mohammad , Fahad Awrad
Published: December 2021

Well integrity is one of the main challenges that are facing operators, finding the source of the well problem and isolating it before a catastrophic event occurs. This study demonstrates the power of integrating different reservoir monitoring and well integrity logs to evaluate well integrity, identify the underlying cause of the potential failure, and providing a potential corrective solution.

Recently, some Injector/producer wells reported migration of injection fluids/gas into shallower sections, charging these formations and increasing the risk of compromised well integrity. Characterization of the well issues required integration of multi-detector pulsed-neutron, well integrity (multi finger caliper, multi-barrier corrosion, cement evaluation, and casing thickness measurements), high precision temperature logs and spectral noise logs. After data integration, detailed analysis was performed to specifically find the unique issues in each well and assess possible corrective actions.

The integrated well integrity logs clearly showed different 9.625-inch and 13.375-inch casings leak points. The reservoir monitoring logs showed lateral and vertical gas and water movements across Wara, Tayarat, Rus, and Radhuma formations. Cement evaluation loges showed no primary cement behind the first barrier casing which was the root cause of the problem. Therefore, the proposed solution, was a cement squeeze. Post squeeze, re-logging occurred, validating zonal isolation and a return of a standard geothermal gradient across the Tayarat formation. Most importantly, the cement evaluation identified good bond from the squeeze point clear to surface, isolating all formations. All these wells were returned to service (injector/producer), daily annular pressure monitoring confirmed that no further pressure build up was seen.

Kuwait Oil Company managed to avoid a catastrophic well integrity event on these wells and utilized the approach presented to take the proper corrective actions, and validate that the action taken resolved the initial well integrity issues. Consequently, the wells were returned to service, and the company avoided a costly high probability blowout.
First Application of Hybrid Bit Technology to Optimize Drilling Through S Shape Directional Section with High Chert Content in UAE Land Operations
Authors: Nunez Ygnacio Jesus , Bashir Munir , Ruiz Fernando , Kumar Rakesh , Sameer Mohamed , Al Mutawa Ahmed Abdulla , Al Shamisi Eisa Daban , Hamdy Ibrahim , Mounir Hesham , Aseel Mohammed , Akbarina Masita
Published: December 2021

This paper highlights the solution, execution, and evaluation of the first 12.25″ application of hybrid bit on rotary steerable system in S-Shape directional application to drill interbedded formations with up to 25 % chert content in UAE land operations.

The main challenge that the solution overcame is to drill through the hard chert layers while avoiding trips due to PDC bit damage nor drilling hour's limitation of TCI bit while improving the overall ROP and achieving the directional requirement. The solution package has demonstrated a superior ROP over rollercone bits, as well as improved PDC cutter durability and lower reactive torque leading to better steerability and stability which will be detailed in this paper.

A significant contributor to such success was utilizing a new hybrid bit technology which incorporates the dual cutting mechanisms of both polycrystalline Diamond Compact (PDC) and rollercone bits. This allows a more efficient drilling by bringing the durability of the crushing action of rollercone to drill through hard interbedded lithology and the effectiveness of the shearing action of PDC cutters to improve ROP without sacrificing the toughness of the cutting structure edge.

The proposed solution in combined with continues proportional rotary steering system managed to drill 4,670 ft through heterogeneous formation with chert nodules, with an average ROP of 38.29 ft\hr improving ROP by 15% and eliminating extra trips of utilizing roller cone bits to be able to drill though the chert nodules and avoid the PDC bit damage.

Leading reduction in cost per foot by 35 %. Additionally, the hybrid bit exceed the expectation achieving 878 thousand of revolutions, with effective bearing and with the drilling cutting structure in a very good condition. Furthermore, the directional objectives were met with high quality directional drilling avoiding wellbore tortuosity. Such success was established through application analysis, specific formations drilling roadmaps and optimized drilling parameters in order to improve the overall run efficiency.

The combination of roller cone and PDC elements in a hybrid bit designed to deliver better efficiency and torque stability significantly increased performance drilling the section in one single run, proven that heterogeneous formations can be drill.
Accurate Pore Fluid Indicator Prediction Using Seismic Fluid Bulk Modulus Inversion
Authors: Jaya Makky Sandra , Ahmad Riza Ghazali , M. Izzuljad Ahmad Fuad , Salbiah Mad Sahad
Published: December 2021

Submitted Abstract

Objectives/Scope

The prediction of fluid parameter related to hydrocarbon presence using seismic data has often been limited by the performance of probability density function in estimating fluid properties from seismic inversion results. A novel fluid bulk modulus inversion (fBMI) is a pre-stack seismic inversion technique that has been developed to allow a direct estimation of pore fluid bulk modulus (Kf) from seismic data. Real data application in Malay basin showcases that Kf volume can be used to pinpoint areas with high probability of hydrocarbon presence.

Methods, Procedures, Process

The fluid term AVO reflectivity (Russell et al., 2011) is used as the basis of our formulation and has been extended to allow direct estimation of pore fluid bulk modulus, shearmodulus, porosity parameter and density through standard least-square inversion. The novel formulation is able to relax the dependency of fluid terms on the porosity. To demonstrate this, verifications were made against standard linear AVO approximations. Our observation shows that the young tertiary basins such as the Malay basin the fluid bulk modulus values have a big contrast between hydrocarbon saturated and water bearing reservoirs with a minimum of 60% ratio difference. The inverted fluid bulk modulus volume provides thus a direct assessment of areas with high probability of hydrocarbon saturation.

Results, Observations, Conclusions

In this paper, the fBMI technique is showcased on a field in the Malay basin. The outcome is demonstrated on a well panel analysis for four wells located across the study area (Figure 1). The inverted fluid bulk modulus extracted along a horizon representing the top of target reservoir is shown in Figure 2b. The blue color indicates high bulk modulus corresponds to water-bearing zone, while the yellow-red color range corresponding to low hydrocarbon-bearing zones. The areas of low fluid bulk modulus values at the north-western region are calibrated to known production zones in that region. fBMI shows areas that delineate high probability of hydrocarbon presence and provides a quantitative measure in terms of fluid parameter directly related to the presence of hydrocarbon saturations. Figure 1: Comparison analysis of water saturation (blue curve) and fluid bulk modulus (red curve) of well log data in the Malay basin. Black strips indicate the coal intervals. Figure 2: a) Inverted acoustic impedance extracted from the top reservoir horizon of a field in the Malay basin. b) The corresponding fluid bulk modulus values from fBMI.

Novel/Additive Information

The fBMI is a new four parameters linear amplitude-versus-offset inversion technique that provides quantitative fluid parameter directly related to fluid bulk modulus from seismic data. It is utilized as a tool for direct hydrocarbon prospect assessment to differentiate gas, oil, condensate and water.
Enhanced Foam Stability Using Nanoparticle in High Salinity High Temperature Condition for Eor Application
Authors: Razali Norzafirah , Chai Ivy Ching Hsia , A Manap Arif Azhan , Mahamad Amir M Iqbal
Published: December 2021

The capability of commercial nanoparticles to perform as foam stabilizer were investigated at reservoir temperature of 96°C. Al2O3, Fe3O4, Co3O4, CuO, MgO, NiO, ZrO2, ZnO and SiO2 nanoparticles that were characterized using XRD, FTIR, FESEM-EDX, TEM and PSA, were blended in the in-house formulated surfactant named IVF respectively at a particular ratio. The test was performed with and without the presence of reservoir crude oil. Results showed that formulation with nanoparticles enhanced foam stability by having longer foam half-life than the IVF surfactant alone, especially in the absence of oil. Only SiO2 nanoparticles were observed to have improved the foam stability in both test conditions. The unique properties of SiO2 as a semi-metal oxide material may have contributed to the insensitivity of SiO2 nanoparticle towards crude oil which is known as a foam destabilizer. The physical barrier that was formed by SiO2 nanoparticles at the foam lamella were probably unaffected by the presence of crude oil, thus allowing the foams to maintain its stability. In thermal stability tests, we observed the instability of all nanoparticles in the IVF formulation at 96°C. Nanoparticles were observed to have separated and settled within 24 hours. Therefore, surface modification of nanoparticle was done to establish steric stabilization by grafting macro-molecule of polymer onto the surface of SiO2. This in-house developed polymer grafted silica nanoparticles are named ZPG nanoparticles. The ZPG nanoparticles passed the thermal stability test at 96°C for a duration of 3 months. In the foam wetness analysis, ZPG nanoparticles were observed to have produced more wet foams than IVF formulation alone, indicating that ZPG is suitable to be used as foam stabilizer for EOR process as it showed catalytic behaviour and thermally well-stable at reservoir temperature.
Highly Efficient and Accurate Gas-Alkane Binary Mixture Interfacial Tension Equations for a Broad Range of Temperatures, Pressures, and Compositions
Authors: Wang Yingnan , Shardt Nadia , Elliott Janet A. W. , Jin Zhehui
Published: December 2021

Gas-alkane interfacial tension (IFT) is an important parameter in the enhanced oil recovery (EOR) process. Thus, it is imperative to obtain an accurate gas-alkane mixture IFT for both chemical and petroleum engineering applications. Various empirical correlations have been developed in the past several decades. Although these models are often easy to implement, their accuracy is inconsistent over a wide range of temperatures, pressures, and compositions. Although statistical mechanics-based models and molecular simulations can accurately predict gas-alkane IFT, they usually come with an extensive computational cost. The Shardt-Elliott (SE) model is a highly accurate IFT model that for subcritical fluids is analytic in terms of temperature T and composition x. In applications, it is desirable to obtain IFT in terms of temperature T and pressure P, which requires time-consuming flash calculations, and for mixtures that contain a gas component greater than its pure species critical point, additional critical composition calculations are required. In this work, the SE model is combined with a machine learning (ML) approach to obtain highly efficient and highly accurate gas-alkane binary mixture IFT equations directly in terms of temperature, pressure, and alkane molar weights. The SE model is used to build an IFT database (more than 36,000 points) for ML training to obtain IFT equations. The ML-based IFT equations are evaluated in comparison with the available experimental data (888 points) and with the SE model, as well as with the less accurate parachor model. Overall, the ML-based IFT equations show excellent agreement with experimental data for gas-alkane binary mixtures over a wide range of T and P, and they outperform the widely used parachor model. The developed highly efficient and highly accurate IFT functions can serve as a basis for modeling gas-alkane binary mixtures for a broad range of T, P, and x.
Genetic Analysis of Yield and its Attributes in Bread Wheat (Triticum Aestivum L. Em. Thell) Under Irrigated and Rainfed Conditions
Authors: Chaudhary Divya , Swati  , Nagar Kuldeep , Dhyani Richa
Published: December 2021

Experiments were conducted to study the genetics and combining ability for yield and its attributes under Irrigated (E1) and Rainfed (E2) conditions using F1 hybrids derived from Line X Tester mating design by crossing eleven lines with three testers. Significant differences were observed among all the genotypes for all the traits in both E1 and E2 environments as well as in pooled analysis. The σ2gca/σ2sca ratio indicated predominance of non-additive gene action for all the characters in both environments. Therefore, this component of variance can be utilize in breeding programme through exploitation of heterosis and the selection process for identification of superior plant type should be postponed to further generations like F4 or F5. VL3001 and KACHU*2//WHEAR/SOKOLL was identified as good general combiner in irrigated condition (E1) and in rainfed condition (E2), respectively for maximum number of traits. Parent VL3001 was also identified as good general combiner for maximum number of traits in case of pooled analysis. Cross BECARD/KACHU × WH1080, BOW/VEE/5/ND/VG9144//KAL/BBB/YACO/4/CHIL/6/CASKOR/3/… × WH1080 and C306 × WH1142 was identified as good specific combination for maximum number of traits in irrigated condition (E1), rainfed condition (E2) and in pooled analysis, respectively.
Development of a Complex Intervention to Support Parents of Chronically Ill Adolescents in Transition From Pediatrics to Adult Care (ParTNer-STEPs)
Authors: Thomsen Ena Lindhart , Esbensen Bente Appel , Hanghøj Signe , Hansson Helena , Boisen Kirsten Arntz
Published: December 2021

Background Transfer from pediatric to adult care for chronically ill adolescents is associated with outpatient non-attendance and low treatment adherence in adolescents, and with anxiety and concerns among parents. Recent studies have shown that parent involvement results in better transitions. The aim of this paper was to describe the development, through participatory design, of a brief transition program targeted to parents of chronically ill adolescents.Methods The study was based on the UK Medical Research Council’s (MRC) framework on developing and testing complex interventions. To increase the program’s feasibility and relevance, participatory design was chosen as the overall method. A collaboration group of parents, adolescents and health care professionals (HCP) were actively involved in the development of the program. The program was developed in three development stages, in accordance with the MRC framework: 1) identifying the evidence base, 2) identifying theory, and 3) modelling process and outcomes. Results Together with the collaboration group, we developed a brief transition program targeting parents, by undertaking an iterative process, involving a literature review, individual interviews, workshops, online brainstorms and multiple pilot tests. The program, called ParTNer-STEPs (Parents in Transition – a Nurse-led Support and Transfer Educational Program) comprised three components: 1) an informative website, 2) online educational events for parents, and 3) transfer consultations with providers from both pediatrics and adult care.Conclusions The MRC framework was successfully applied to develop a brief transition program targeting parents of chronically ill adolescents. By incorporating the principles of participatory design in the development phase, we ensured that both parents’ and adolescents’ needs were represented and addressed in the program. Furthermore, the involvement of HCPs ensured the feasibility and relevance of the intervention in clinical practice and will increase the chances of successful implementation.Trial registration ClinicalTrials.gov ID NCT04969328
Genetic Algorithm-Based Hybrid Spectrum Handoff Strategy in Cognitive Radio-Based Internet of Things
Authors: Miao Liu , Qing He , Huo Zhuo-Miao , Sun Zhen-Xing , Di Xu
Published: December 2021

In Cognitive radio-based Internet of Things (CR-IoT) systems, the return of the primary user (PU) causes the secondary user (SU) that is communicating to face the spectrum handoff problem. In the process of spectrum handoff, the user terminal can’t get the idle channels in time because of the unknown channel usage state.
To solve this problem, a hybrid spectrum handoff algorithm based on the channel idle probability is proposed. The
algorithm considers the regularity of PU activities in space and time, defines the idle probability of channels from
the perspective of week attributes and time periods, obtains the optimal time period length using genetic algorithm, generates a channel idle probability table, and provides the target channel sequence for SUs in combination with the proposed channel ordering scheme. Simulation results show that the hybrid spectrum switching algorithm based on the channel idle probability can reduce the energy consumption of SUs during spectrum switching, reduce the communication interruption rate, enable SUs to find idle channels faster and reduce the number of sensing times.
Trends of overweight and obesity among preschool children from 2013 to 2018: A cross-sectional study in Rhine-Neckar County and the City of Heidelberg, Germany
Authors: Liu Weina , Dambach Peter , He Mike Z. , Schwertz Rainer , Chen Simiao , Yu Fengyun , Marx Michael
Published: December 2021

BackgroundEarly childhood overweight and obesity is a growing public health concern worldwide. Few recent studies have addressed how time trends varied by sociodemographic characteristics at the regional level using large and high-quality data. This study aims to determine how time trends vary in the prevalence of early childhood overweight and obesity by age, gender, and migration background at the regional level.MethodsWe described the distribution change in the BMI with a Kernel-density curve, and evaluated the trends of overweight and obesity by age, gender, and migration background using logistic regression.ResultsMean BMI and the prevalence of overweight and obesity increased among preschool children aged 4-6 years in the Rhine-Neckar County and the City of Heidelberg. After adjusting for age, gender, and migration background, trends in the prevelance of overweight significantly increased only among male children in the age 5 year group with migration background (P < 0.05), and an upward trend of obesity was observed only among male children in the age 5 year group and female children in the age 6 year group with migration background (P < 0.05).Conclusions﻿BMI distribution as well as general prevalence of overweight and obesity are still increasing among preschool children. Children with migration backgrounds, particularly male children in the age 5 year groups and female children in the age 6 year group should be prioritized. More prevention policies should be targeted towards vulnerable groups.
Field Study for PAH Absorption Performances of Butyl Rubber, PDMS, and SPMD Passive Samplers
Authors: Tureyen Oktay Eren , Yakan Sevil Deniz , Yilmaz Atilla , Yetiskin Berkant , Okay Oguz , Okay Oya S.
Published: December 2021

Polycyclic aromatic hydrocarbons (PAHs) are organic pollutants having various adverse effects on the marine ecosystem. Because of their low solubility in the marine environment, their detection and monitoring in the water column are challenging tasks. Passive samplers are used to detect PAHs in aquatic environments as complementary tools to conventional water sampling. In the present study, PAH absorbance performances of four butyl rubber-based (BR) passive samplers with different structures (SN5, SN10, DN, and TN) and commercialized passive samplers (SPMD and PDMS) were determined. Stainless steel cages containing passive samplers were deployed in the water column in Istinye Bay, Istanbul, and retrieved after 7 and 28 days. Collected samplers were analyzed in the laboratory to determine their PAH contents. Results showed that, even though the SPMD samplers had the highest total PAH content, they were not able to collect PAHs with log Kow value of above 6.0. Similarly, PAHs with log Kow values higher than 5.5 could have not been collected by PDMS samplers. In contrast, BR-based passive samplers have sampled also high molecular weight PAHs in the water column, and SN10 sampler showed the highest performance in terms of the collected PAHs. Results highlighted that SN10 sampler has a wide absorption range when it is compared with the commercialized samplers, and it has also advanced absorption performance relative to the other BR samplers.
Where’S the “Everyday Black Woman”? an Intersectional Qualitative Analysis of Black Women’S Decision-Making Regarding HIV Pre-Exposure Prophylaxis (PrEP) in Mississippi
Authors: Willie Tiara C. , Knight Deja , Baral Stefan D. , Chan Philip A. , Kershaw Trace , Mayer Kenneth H. , Stockman Jamila K. , Adimora Adaora A. , Monger Mauda , Mena Leandro A. , Philllips Karlye A. , Nunn Amy
Published: December 2021

Background

Black cisgender women in the U.S. South bear a disproportionate burden of HIV compared to cisgender women in other racial and ethnic groups and in any other part of the US. Critical to decreasing new HIV infections is the improved delivery of pre-exposure prophylaxis (PrEP) for Black cisgender women as it remains underutilized in 2021. Informed by intersectionality, the study sought to characterize the sociostructural influences on Black cisgender women’s deliberations about PrEP within the context of interlocking systems of oppression including racism, sexism, and classism.
Methods

Six focus groups were conducted with 37 Black women residing in Jackson, Mississippi. This sample was purposively recruited to include Black cisgender women who were eligible for PrEP but had never received a PrEP prescription.
Results

Six themes were identified as obstacles during PrEP deliberation among Black women: 1) limited PrEP awareness, 2) low perceived HIV risk, 3) concerns about side effects, 4) concerns about costs, 5) limited marketing, and 6) distrust in the healthcare system. Three themes were identified as facilitators during PrEP deliberations: 1) women’s empowerment and advocacy, 2) need for increased PrEP-specific education, and 3) the positive influence of PrEP-engaged women’s testimonials. Black women shared a limited awareness of PrEP exacerbated by the lack of Black women-specific marketing. Opportunities to support Black women-specific social marketing could increase awareness and knowledge regarding PrEP’s benefits and costs. Black women also shared their concerns about discrimination in healthcare and distrust, but they felt that these barriers may be addressed by patient testimonials from PrEP-engaged Black women, empowerment strategies, and directly addressing provider biases.
Conclusions

An effective response to PrEP implementation among Black women in the South requires developing programs to center the needs of Black women and carry out active strategies that prioritize peer advocacy while reinforcing positive and mitigating negative influences from broader social and historical contexts.
Phytochemical, Heavy Metals and Antimicrobial Study of the Leaves of Calopogonium Mucunoides
Authors: Emenike Ebuka Chizitere , Chukwuebuka Onyema
Published: December 2021

Background: In this study, the phytochemical, heavy metals, and antimicrobial characteristics of the leaves of Calopogonium mucunoides were investigated in other to determine its therapeutic potentials. The phytochemicals present in the leaves were extracted with n-hexane, methanol and ethyl acetate, and the extracts were used to investigate for the phytochemical constituents and antimicrobial activity. The methanol extract was used to test for the concentration of five heavy metals.Results: The result of the phytochemical screening confirmed the presence of alkaloids, anthocyanins, flavonoids, glycosides, phenols, reducing sugars, saponins, steroids, tannins, and terpenoids in various quantities. The heavy metals analysis result revealed the presence of lead (0.08 mg/kg) and iron (0.08 mg/kg) well below the acceptable limits set by the World Health Organization for heavy metals in plants, while cadmium, nickel and zinc were found to be below detectable limits. The extracts were tested against thirteen human pathogens (ten bacteria and three fungi) using the disk diffusion method. The extracts possessed a broad range of microbial activities, with the methanolic extract reportedly showing the highest zone of inhibition (31 mm) against Bacillus sp. while the n-hexane extract did not show any antimicrobial activity in the whole test organisms.Conclusion: The results obtained revealed that the leaves of C. mucunoides has some therapeutic values and could be exploited in the preparation of herbal drugs for the treatment of various ailments.
Peripheral Interleukin-18 Is Negatively Correlated With Abnormal Brain Activity In Patients With Depression: A Resting-State fMRI Study
Authors: Du Xiangdong , Zou Siyun , Yue Yan , Fang Xiaojia , Wu Yuxuan , Wu Siqi , Wang Haitao , Li Zhe , Zhao Xueli , Yin Ming , Ye Gang , Sun Hongyan , Gu Xiaochu , Zhang Xiaobin , Miao Zhigang , Jin Jeff Wang , Wu Hanjing Emily , Liu Yansong , Xu Xingshun
Published: December 2021

Background: Interleukin-18 (IL-18) may participate in the development of major depressive disorder, but the specific mechanism remains unclear. This study aimed to explore whether IL-18 correlates with areas of the brain associated with depression.Methods: Using a case-control design, 68 subjects (34 patients and 34 healthy controls) underwent clinical assessment, blood sampling, and resting-state functional Magnetic Resonance Imaging (fMRI). The total Hamilton depression-17 (HAMD-17) score was used to assess depression severity. Enzyme-linked immunosorbent assay (ELISA) was used to detect IL-18 levels. Rest-state fMRI was conducted to explore the spontaneous brain activity. Results: The level of IL-18 was higher in patients with depression in comparison with health controls. IL-18 and degree centrality (DC) were negatively correlated with the left posterior cingulate gyrus in the depression patient group, but no correlation was found in the healthy control group. Conclusion: This study suggests the involvement of IL-18 in the pathophysiological mechanism for depression and interference with brain activity.