bluuebunny/crossref_metadata_2025 huggingface dataset:
Determinants of Low Birth Weight in the Kenge Health Zone, a (post-) conflict setting, DR Congo: A Multicenter Case–Control Study
Authors: Muzingu Jeannette , Kabasubabo Francis K , Akilimali Pierre Z
Published: June 2024

: Background: Low birth weight (LBW) is a major public health problem in low-income countries. Infants born with LBW are at increased risk of neonatal mortality, have poorer school performance, and are more likely to develop respiratory and cardiovascular diseases in adulthood. Methods: An unmatched case–control study was conducted in five maternity wards in the Kenge Health Zone, involving 159 mother–newborn pairs. Data analysis was performed using STATA 18.0 software. Bivariate and multivariate analyses were used to determine the associations between independent variables and LBW. Results: Determinants of low birth weight were maternal short stature (height < 155 cm) (adjusted odds ratio (AOR): 3.90; 95% confidence interval (CI): 1.66–9.13), maternal non-indigenous Yaka ethnic group (AOR: 2.39; 95% CI: 1.01–5.66), having attended fewer antenatal care (ANC) sessions (AOR: 0.73; 95% CI: 0.53–0.99), and inadequate maternal dietary diversity (AOR: 3.97; 95% CI: 1.25–12.62). Conclusions: Increased education and awareness of dietary diversity as an indicator of dietary quality in women of childbearing age, especially during pregnancy, along with regular follow-up of antenatal care visits and behavior change communication targeting pregnant women, can help health professionals address dietary taboos and reduce the incidence of LBW.
Spread Spectrum Induced Polarization Survey for Qiushuwan Copper-Molybdenum Deposits in South of Henan Province, China.
Authors: Ahmad Jawad , Chen Rujun , Ahmed Ijaz , Yaseen Muhammad , Fahad Shah , Rahim Osama Abdul , Ullah Farid , Shah Shahid Ali , Rui Li
Published: June 2024

The Qiushuwan Cu-Mo deposit, located in the East Qinling molybdenum belt, which is a major mining site recognized for its enormous reserves of medium-sized molybdenum. In order to enhance our comprehension and ascertain supplementary mineral resources, it is critical to conduct an in-depth investigation of both the deep and peripheral regions. The primary goal of this study is to investigate the Qiushuwan Copper Molybdenum Mine, which is located in Zhenping County, Henan Province. The spread spectrum-induced polarization (SSIP) method is utilized as a means of conducting mining exploratory analysis. Significant findings have been obtained through the collection of SSIP data, geological analysis, and electrical parameter study of rock and ore samples along profile-80. By conducting a meticulous examination of the SSIP data at suitable frequencies, two prominent conductive ore bodies, specifically C2 and C4, have been successfully discovered. C2 exhibits a correlation with granite porphyry and molybdenum veins, while C4 is linked to a skarn deposit that contains a concentration of copper ore. The spatial differences in conductivity within the research area have been precisely characterized using resistivity models obtained from the SSIP data. The precision and dependability of our conclusions have been confirmed through the integration of borehole data and the matching of geological sections with inversion models. The recovered core samples show a diverse range of minerals, containing both valuable ores and minerals that have undergone alteration. Pyrite constantly appears with molybdenite in the majority of samples. The aforementioned results provide a strong foundation for future exploration initiatives and sustainable resource exploitation, enabling informed decision-making in the effective use and administration of natural resources. This study adds to the existing body of knowledge on the Qiushuwan Cu-Mo deposit and improves exploration methods in the region by utilizing the SSIP approach. The findings are a useful asset for geologists, mining experts, and stakeholders, offering essential knowledge for future exploration and sustainable utilization of resources.
Mechanical performance of bentonite plugs in abandonment operations of petroleum wells
Authors: Oliveira Laura Rafaela Cavalcanti de , Lima Mário César de Siqueira , Costa Waleska Rodrigues Pontes da , Gonçalves Ruth Luna do Nascimento , Costa Anna Carolina Amorim , Nóbrega Karine Castro , Nascimento Renalle Cristina Alves de Medeiros , Souza Elessandre Alves de , Oliveira Tiago Almeida de , Barros Michelli , Amorim Luciana Viana
Published: June 2024

This study aims to evaluate how the operational procedure adopted for the pellets placement and the exposure to subsurface conditions influences the mechanical integrity of bentonite plugs used as barrier elements in the abandonment of petroleum wells. To this end, two methodologies were used to obtain the plugs: from the first methodology, the pellets were immersed in diesel or olefin, which are proposed as displacement fluids in offshore operations, and then, hydrated in deionized water; in the second methodology, representative of onshore operations, the pellets were directly hydrated in deionized water. After that, the plugs were tested by compression and adhesion tests. These mechanical tests were also carried out for test specimens obtained from plugs exposed to four formulations of synthetic formation waters. The results obtained demonstrated that the previous contact with olefin adversely affects the mechanical stability of bentonite plugs, while plugs formed from pellets immersed in diesel presented satisfactory mechanical properties. The mechanical properties of onshore plugs attested the highly successful performance of these elements, once its compressive strength was minimally impacted by exposure to formation waters and more pronounced reductions were observed only in the adhesion properties after the contact with higher salinity formation waters.
Effect of Various Mineral Admixtures on the Mechanical and Microstructural Properties of Self-Compacting Geopolymer Concrete
Authors: M AMALA , C UMARANI
Published: June 2024

An innovative concrete that incorporates the advantages of self-compacting concrete with geopolymer is called self-compacting geopolymer concrete. The objective of this study was the Manufacturing of M30-grade self-compacting geopolymer concrete by adding industrial materials like fly ash (FA), ultrafine ground granulated blast furnace slag (UFGGBS), and silica fume (SF) as minerals. The disposal of these industrial wastes can be substantially overcome, as they lead to land pollution. The fixed powder content was 500 kg/m3. A mixture of sodium silicate (Na2SiO3) and sodium hydroxide (NaOH) created an alkaline solution that activated the cementitious binders. In this study, slump flow, L-box, V Funnel, T50 V Funnel, and J ring tests were carried out to determine the fresh qualities of the concrete. These tests were conducted under the regulations for self-compacting concrete provided by EFNARC (2005). To improve the flexural strength of the SCGC, 1.5 % glass fibre was added. This study illustrates how an artificial neural network (ANN) model can determine the concrete mix proportion. The characteristics of SCGC, both fresh and hardened properties test were investigated for molarities of 8, 10, and 12. The microstructural outcomes were determined using Fourier-transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), and X-ray diffraction (XRD).
Assessing Spatial-Temporal Characteristics of Land Desertification from 1990–2020 in the Heihe River Basin Using Landsat Series Imagery
Authors: Liao Jie , Yang Xianzhong , Ye Qiyan , Wan Kaiming , Sheng Jixing , Zhang Shengyin , Song Xiang
Published: June 2024

Monitoring the status and dynamics of desertification is one of the most important parts of combating desertification. In this study, 30m high-resolution information on land desertification and restoration in the HRB was extracted from the land cover database. The results indicate that land desertification coexists with land restoration in the HRB. At different periods, the area of land restoration is much larger than the area of land desertification in the HRB, and the HRB has been in a process of land restoration. Upstream of the HRB, there is a continuing trend of increasing land desertification associated with overgrazing in a context where climate change favors desertification reversal. In the middle and lower reaches, although both climate variability and human activities favor land desertification, the process of land desertification in the middle and lower reaches is still being reversed and land restoration dominates. The implementation of the Eco-Environmental Protection Project and desertification control measures, especially the EWDP, is contributing to the reversal of desertification in the middle and lower reaches of the HRB. However, the EWDP has indirectly led to the lowering of the water table in the middle reaches, resulting in local vegetation degradation. Therefore, there is therefore an urgent need to transform the economic structure of the middle reaches to cope with water scarcity and land desertification.
Sustainable Synergy: Areca Sheath Paper Cups from Waste to Wonder
Authors: M Raghul
Published: June 2024

Areca palm sheath leaves were an incredibly noble food packaging system. In ancient times, naturally available wood, leaves, stems, and barks were used to store food materials. But all these were turned down upon the rise of civilization. Today, many modern food packaging systems are used; paper and paperboard packaging materials are used mainly as a replacement for plastic materials. But somehow, paper-based materials have major drawbacks when temperature-dependent products are stored; leaching out components poses a higher threat to health. To alleviate it, bio-based components were used in the manufacturing of paper materials, but the migration of those components was still risky. This study focuses on how the areca palm sheath leaves can be effectively used to prevent this migration of components.
Effect of Fungal Solid-State Fermentation on the Profile of Phenolic Compounds and on the Nutritional Properties of Grape Pomace
Authors: Šelo Gordana , Planinić Mirela , Tišma Marina , Klarić Ana-Marija , Bucić-Kojić Ana
Published: June 2024

Grape pomace (GP) is considered a natural source of bioactive compounds. To improve the ex-tractability of bioactive compounds, in this work GP was biologically treated for 15 days with the white-rot fungus Trametes versicolor in laboratory jars and a tray bioreactor under solid-state fermentation (SSF) conditions. During SSF, the activity of lignolytic (laccase, manganese peroxi-dase) and hydrolytic (xylanase, cellulase, β-glucosidase and invertase) enzymes was measured, with the activity of laccase (2.66 U/gdb in jars and 0.96 U/gdb in the bioreactor) and xylanase (346.04 U/gdb in jars and 200.65 U/gdb in the bioreactor) being the highest. The effect of the com-plex enzyme system was reflected in the changes in the chemical composition of GP with in-creasing ash, crude protein and free fat content: 28%, 10% and 17% in the laboratory jars and 29%, 11% and 7% in the bioreactor, respectively. In addition, the biological treatment had a positive effect on the extractability of 13 individual phenolic compounds. Therefore, the applied SSF technique represents an effective strategy to improve the profile of phenolic compounds and the nutritional composition of GP, promoting their valorization and opening the door for potential application in the food industry and other sectors.
Insights into Positive Mental Health amid the Covid-19 Pandemic: Evidence from a Study in Croatia
Authors: Jovanović Željko , Spevan Marija , Boskovic Sandra , Svaljug Deana , Miletic Bojan
Published: June 2024

Objective: The Covid-19 pandemic has raised significant concerns about public health, particularly in terms of mental well-being due to heightened fear and uncertainty. The findings of this study are based on a survey conducted to evaluate the mental health status of the general population in Croatia during the Covid-19 pandemic.
Methods: A survey conducted randomly and cross-sectionally included 588 respondents from all 21 counties in Croatia. The survey gathered demographic data and assessed various factors related to pandemic response measures and mental health using the Mental Health Continuum-Short Form (MHC-SF) scale.
Results: Despite feeling adequately informed about Covid-19 (76.0%), most respondents (60.8%) expressed concerns about their loved ones during the pandemic. There were significant numbers who felt there was no risk of infection (50.9%) or believed they would not get infected (40.2%), while 72.4% were content with government measures. Statistical analysis indicated that mental health was not significantly different between genders, but age-related differences were evident, with those under 21 experiencing the most distress. The lowest level of psychological and social well-being was observed in respondents who were unemployed.
Conclusions: The study identifies vulnerable groups in the Croatian population during the pandemic, including younger individuals, those on parental leave, students, and the unemployed, who exhibited worse mental health. The importance of implementing targeted mental health interventions to support these vulnerable groups is highlighted by these findings.
MEDOIDS AS A PACKING OF ORB IMAGE DESCRIPTORS
Authors: Gorokhovatskyi Oleksii , Yakovleva Olena
Published: June 2024

The aim of the research. The paper presents the research about the feasibility to use matching medoids obtained from the set of ORB descriptors instead matching the full set of binary descriptors for image classification problem. Research results. Different methods that include direct brute force medoids matching, grouping of medoids for separate classes, and grouping of descriptors followed by calculation of medoids amongst them were proposed. Numerical experiments were performed for all these methods in order to compare the classification accuracy and inference time. It has been shown that using of medoids allowed us to redistribute processing time in order to perform more calculations during preprocessing rather than during classification. According to modelling performed on the Leeds Butterly dataset matching images based on medoids could have the same accuracy as matching of descriptors (0.69–0.88 for different number of features). Medoids require additional time for the calculation during preprocessing stage but classification time becomes faster: in our experiments we have obtained about 9–10 times faster classification and same 9–10 times increasing preprocessing time for the models that have comparable accuracies. Finally, the efficiency of the proposed ideas was compared to the CNN trained and evaluated on the same data. As expected, CNN required much more preprocessing (training) time but the result is worth it: this approach provides the best classification accuracy and inference time. Conclusion. Medoids matching could have the same accuracy as direct descriptors matching, but the usage of medoids allows us to redistribute the overall modeling time with the increasing preprocessing time and making inference faster.
THE METHOD OF RANKING EFFECTIVE PROJECT SOLUTIONS IN CONDITIONS OF INCOMPLETE CERTAINTY
Authors: Bezkorovainyi Volodymyr , Kolesnyk Liudmyla , Gopejenko Viktors , Kosenko Viktor
Published: June 2024

The subject of research in the article is the process of ranking options in support systems for project decision-making under conditions of incomplete certainty. The goal of the work is to increase the efficiency of technologies for automated design of complex systems due to the development of a combined method of ranking effective options for building objects in conditions of incomplete certainty of input data. The following tasks are solved in the article: analysis of the current state of the problem of ranking options in support systems for project decision-making; decomposition of problems of system optimization of complex design objects and support of project decision-making; development of a variant ranking method that combines the procedures of lexicographic optimization and cardinal ordering in conditions of incomplete certainty of input data. The following methods are used: systems theory, utility theory, optimization, operations research, interval and fuzzy mathematics. Results. According to the results of the analysis of the problem of supporting project decision-making, the existence of the problem of correctly reducing subsets of effective options for ranking, taking into account factors that are difficult to formalize and the experience of the decision-maker (DM), was established. Decomposition of the problems of system optimization of complex design objects and support for project decision-making was carried out. For the case of ordinalistic presentation of preferences between local criteria, an estimate of the size of the rational reduction of subsets of optimal and suboptimal options for each of the indicators is proposed. Its use allows for one approach to obtain a subset of effective variants of a given capacity for analysis and final selection of the DM. A method of transforming the ordinalistic presentation of preferences between local criteria to their quantitative presentation in the form of weighting coefficients is proposed. Conclusions. The developed methods expand the methodological foundations of the automation of processes supporting the adoption of multi-criteria project decisions. They make it possible to correctly reduce the set of effective alternatives in conditions of incomplete certainty of the input data for the final choice, taking into account factors that are difficult to formalize, knowledge and experience of ODA. The practical use of the obtained results will allow to reduce the time and capacity complexity of the procedures for supporting project decision-making, and due to the use of the technology of selection of subsets of effective options with intervally specified characteristics - to guarantee the quality of project decisions and to provide a more complete assessment of them.
COMPARATIVE ANALYSIS OF SPECTRAL ANOMALIES DETECTION METHODS ON IMAGES FROM ON-BOARD REMOTE SENSING SYSTEMS
Authors: Hurin Artem , Khudov Hennadii , Kostyria Oleksandr , Maslenko Oleh , Siadrystyi Serhii
Published: June 2024

The subject matter of the article is methods of detecting spectral anomalies on images from remote sensing systems. The goal is to conduct a comparative analysis of methods for detecting spectral anomalies on images from remote sensing systems. The tasks are: analysis of the main methods of detecting spectral anomalies on images from remote sensing systems; processing of images from remote sensing systems using basic methods of detecting spectral anomalies; comparative assessment of the quality of methods for detecting spectral anomalies on images from remote monitoring systems. The methods used are: methods of digital image processing, mathematical apparatus of matrix theory, methods of mathematical modeling, methods of optimization theory, analytical and empirical methods of image comparison. The following results are obtained. The main methods of detecting spectral anomalies on images from remote sensing systems were analyzed. Processing of images from remote sensing systems using the basic methods of detecting spectral anomalies was carried out. A comparative assessment of the quality of methods for detecting spectral anomalies on images from remote monitoring systems was carried out. Conclusions. The spectral difference of the considered methods is revealed by the value of information indicators - Euclidean distance, Mahalanobis distance, brightness contrast, and Kullback-Leibler information divergence. Mathematical modeling of the considered methods of detecting spectral anomalies of images with a relatively “simple” and complicated background was carried out. It was established that when searching for a spectral anomaly on an image with a complicated background, the method based on the Kullback-Leibler divergence can be more effective than the other considered methods, but is not optimal. When determining several areas of the image with high divergence indicators, they should be additionally investigated using the specified methods in order to more accurately determine the position of the spectral anomaly.
ANALYSIS OF THE EFFECT OF CONTRACT CHANGE ORDER FACTORS ON THE PERFORMANCE OF ROAD FACILITY PROJECTS
Authors: Lailatul Qomariah Dhona , Susetyo Budi
Published: June 2024

Road facilities are part of the national transportation system according to Article 25 in Law of the Republic of Indonesia Number 22 of 2009 concerning Road Traffic and Transportation. Road facilities in the form of sidewalks and crossings are crossings for pedestrians. The arrangement of sidewalks by the DKI Jakarta Provincial Government is to improve urban infrastructure, where the percentage of sidewalk arrangements by 2022 will reach 5.58% of the length of roads in Jakarta. This research aims to determine the influence of factors Contract Change Order (CCO) on cost performance and implementation time for sidewalk arrangement activities, using structural equation modeling techniques-partial least squares (SEM-PLS). This research focuses on identifying the main CCO factors that directly influence cost performance, and indirectly influence implementation time performance through cost performance on road facility projects. There are 3 (three) types of research variables used; The independent variables consist of scope of work, planning, policy changes, specification changes, and coordination of related parties, the dependent variable is cost performance and the intervening variable is cost performance as a mediating variable of the influence of the CCO factor on time performance. The results showed that the coordination of related parties had a direct and significant positive impact on cost performance by 59%, and an indirect and significant impact on time performance through cost performance as a mediating variable by 37.7%.
ANALYSIS THE INFLUENCE OF VARIATION SHEAR REINFORCEMENT SPACING IN REINFORCED CONCRETE BEAM TESTING
Authors: Tampubolon Sudarno P , Antonius Dikky
Published: June 2024

Beams are crucial components of a building structure that require attention during the design phase. Several failures in beams occur due to inadequate installation of reinforcement according to the planned procedures or designs, which can lead to structural failures. Based on the analysis and testing of three reinforced concrete beams B1, B2, and B3 conducted in the laboratory, the maximum axial compressive strength obtained is 125 kN and the flexural tensile strength is 5.56 MPa. The deflection values observed for beam B1 7.05 mm, beam B2 8.4 mm, and beam B3 18.75 mm. The crack widths observed for beam B1 range from 0.1 to 0.4 cm, beam B2 range from 0.1 to 5 cm, and beam B3 range from 0.1 to 12 cm. Deflection values and crack patterns/failure modes observed in reinforced concrete beams B1, B2, and B3, it is evident that the most significant failure patterns occur in Beam B3 with a stirrup spacing @200mm compared to stirrup spacings @100mm and @150 mm. The use of 45° hooks on stirrups results in diagonal failure in beams. This is attributed to the strong bond between the concrete and the installed reinforcement, thereby interlocking with each other.
THE EFFECT OF BUILDING INFORMATION MODELLING (BIM) METHOD IMPLEMENTATION ON THE EFFECTIVENES OF BUILDING CONSTRUCTION IMPLEMENTATION MANAGEMMENT IN THE CONSTRUCTION INDUSTRY
Authors: Siregar Immanuel  Simon Zevanya , Simanjuntak Pinondang , Purnomo Candra Christianti
Published: June 2024

The aim of this study is to analyze the impact of Building Implementation Information Modeling (BIM) on the efficiency of building construction management quantitatively. It has become a significant method in the construction industry with the potential to improve collaboration, coordination and information management in the implementation of construction projects. The research method uses simple linear regression analysis with data from construction professional respondents. The study involved 52 contractor companies in the construction industry. The selection of these samples is aimed at obtaining representative and adequate data for simple linear regression analysis. With large sample sizes, the results are expected to be more accurate and reliable. In addition, the selection of 52 respondents is also carried out to cover a variety of perspectives and professional experience of construction, making the data obtained more representative, and more reliable for the analysis performed. Implementation of BIM has a significant and positive impact on building construction management, demonstrated by a count t value = 12.217 greater than the table t value of 2.00856. The determination coefficient (R-square) of 0.749 or 74.9% suggests that 74.9 percent variation in building management efficiency can be explained by the implementation of BIM. This finding emphasizes the importance of using BIM to improve management effectiveness in building construction in the construction industry. The implications of this research provide a basis for encouraging the adoption of BIM as an effective tool in the management of construction projects.
From Janissaries to Leaders: The Continuing History of the Kuloghlis in Libya
Authors: Kaya Yakup , Gönlühoş Elmas Merve
Published: June 2024

This article explores the nuanced presence of a distinct Turkish lineage known as the Kuloghlis in the Maghreb region, focusing primarily on Libya. While examining their historical influence on shaping the Ottoman Empire in the region, the article argues that their connection to the Turkish Republic today and their impact on the socio-political landscape persist. Originating from intermarriages between Turkish Janissaries and local women, the Kuloghlis played a crucial role in facilitating Ottoman influence in the Maghreb from the 16th century onward. While their importance waned during the reign of Sultan Abdulhamit II, they maintained ties with Türkiye and experienced a resurgence in prominence after Libya gained independence. Despite the gradually improving literature, scholarly focus lacks in examining the enduring significance of the Kuloghlis, particularly in Libyan politics. Through document analysis and literature review, it illuminates their integral role in Ottoman history and their ongoing relevance in post-independence Libya, where many influential figures can trace their ancestry to this distinctive group.
Thyroid Hormones and Their Role in Male Infertility: A Comprehensive Review
Authors: Hussein Ramadan
Published: June 2024

Thyroid hormones are pivotal regulators of various physiological processes, including reproductive function. While the impact of thyroid dysfunction on female fertility has been extensively studied, its association with male infertility has gained increasing recognition. This comprehensive review explores the role of thyroid hormones in male infertility, focusing on their effects on spermatogenesis, sperm quality, and reproductive outcomes. The review delves into the physiology of thyroid hormones, the presence of thyroid hormone receptors in the male reproductive system, and the influence of thyroid dysfunction on spermatogenesis and semen parameters. Additionally, it examines the molecular mechanisms underlying thyroid hormone action in the male reproductive system and discusses potential therapeutic strategies targeting thyroid hormone pathways to improve male fertility. Understanding the intricate relationship between thyroid hormones and male infertility is crucial for advancing diagnostic and therapeutic approaches in the management of male infertility associated with thyroid dysfunction.
Integrating Digital Tools to Optimise Scale Management – Case Studies
Authors: Bourne H M , Hosein S , Keilty G , Kuijpers K , Rawi Z , Kaasa B.
Published: June 2024

Information is crucial for effective scale management, and it is often the case that scaling events could have been avoided if operations were aware of the evolving risk in real time. Scale management requires an understanding of the produced fluids and the scale threat they create in different parts of the production system as temperatures, pressures and fluid rates change. It requires the timely deployment of preventative and or remedial barriers and appropriate monitoring to ensure these barriers are maintained.

Understanding the parameters that have an impact on the scale risk and the monitoring required to ensure barrier health can be an arduous, manually intensive task, relying on the retrieval and review of source data from multiple locations. However, gaps in this data can lead to an incomplete understanding of the scale risk and/or the barrier health which could result in unexpected scaling events requiring costly intervention work and production deferrals.

This paper describes the suite of cloud based ‘digital twin’ tools that bp has developed and is integrating into its operations, providing on-line, real-time calculation of the scale risk and the health of the barrier deployed to manage the risk on a well-by-well basis. The paper presents field case studies where the suite of tools, integrated into a dashboard, have been implemented. The first, a field that has previously experienced a scaling event after changes in well operating conditions, describes how on-line scale prediction coupled to water chemistry and environmental scanning electron microscopy (ESEM) analysis now provides the operation with live updates on the risk and health of the deployed barriers supporting the timely planning or suspension of treatments.

Other case studies describe the integration of the digital dashboard to specifically optimise wash water injection rates to manage halite in an asset with produced water handling constraints and the use of a squeeze life rate tracker to enhance treatment scheduling. This case describes how the adoption of digital tools allows rapid decision making and minimising over treatment of wash water injection and the impact this has on production.
Beyond Windows: Glass Solid Scale Inhibitors with Controlled Release at Elevated Temperatures for Extended Carbonate Scale Protection in the Laboratory and Field
Authors: Gilmer Chad , Sutherland Louise , Jordan Myles , Lee Jesse
Published: June 2024

Gas condensate fields often have multiple reservoirs with different water chemistries, and they contain varying concentrations of carbonates and CO2 in solution. One challenge associated with these types of fields is that calcium carbonate scale may form during gas production when water sources from different zones comingle with the gas, ultimately reducing gas production. A proactive approach to mitigate carbonate scale utilized a new technology, glass solid scale inhibitors, to show extended protection in both laboratory and field studies.

Laboratory tests were conducted to study the release profile of the glass scale inhibitors (SI) at 150 °C. The SI's were placed in a metal pouch, submerged in deionized water, and placed in a high temperature high pressure apparatus. The apparatus was placed in an oven, and the weight loss was monitored for over a year. The results showed that SI's were able to show controlled release of the active component for over 1 year. Minimum inhibitor concentration (MIC) testing was also conducted using field brines that showed a risk for carbonate scale formation. Dynamic scale loop (DSL) testing determined the MIC to be as low as 0.1 ppm. The results suggest that it is possible to achieve extended protection at low concentrations for over 1 year.

The glass scale inhibitors were deployed in a field trial and the produced water was collected to monitor the residual SI concentration. The glass SI's are easily added with the proppant into the frac fluid and placed in the fracture along with the proppant to provide scale protection deep in the reservoir. Field data showed that the product was able to sustain the MIC up to 2 years after application, in high temperature wells of 125 °C. Three wells treated showed no indication of scale formation 9 months after application. The new technology offers an alternative method to proactively treat carbonate scale formation in wells being fractured to enhance production. With extended protection, it is possible to reduce costly squeeze treatments or continuous application, while potentially reducing extra carbon emissions associated with traditional scale treatments.
Strategic Scale Mitigation for Oil Wells with a Low Basic Sediment and Water
Authors: Benkhaled M. , Tort F. , Baraka-Lokmane S. , Fretard D. , Lesage N.
Published: June 2024

The study concerns an onshore oil field in Southern Europe where wells are facing productivity decline. Both asphaltene and inorganic scale risks have been predicted at project phase. Since the Water Cut is close to 1%, no scale deposition was anticipated and the suspected cause for productivity reduction was either linked to the poor performance of Electrical Submersible Pumps (ESPs) and/or the poor efficiency of the asphaltene inhibitor.

The objective of the study is to investigate the cause of the productivity reduction. Deposit analysis collected on ESPs showed that it is composed of 95% of aragonite and 5% of organic material. Two hypotheses have been proposed: (1) Erosion of the carbonate reservoir, resulting in deposition on the ESPs or (2) Precipitation of Aragonite on the ESP due to thermodynamic variations and turbulent flow regime. Since aragonite is a metastable calcium carbonate mineral, not present in the reservoir, hypothesis 2 was selected. In the context of a very low water cut (around 1%), the challenge was to develop a novel chemical product able to prevent scale deposition. Two products have been tested in the laboratory and on site: a scale treater (STA) and a multifunction product (MFB), to prevent both asphaltene and scale. The scale treater was designed to modify the adhesion of scale with the formation of a protective film on the metallic surface. The second chemical (MFB) has been developed by combining the STA with an asphaltene inhibitor. This multifunction product has allowed to prevent incompatibility issues between chemicals and helped in the reduction of OPEX. Laboratory and field tests with STA and MFB have shown good results; both products were able to prevent scale deposition on the ESPs and improve productivity. STA and MFB products helped to improve productivity where a scale inhibitor could not be used because of the very low basic sediment and water (BSW). As soon as the BSW reaches 5%, the mitigation strategy could be to switch to two separate products: scale and asphaltene inhibitors; unless further tests show that MFB performs also for higher BSW.
Understanding the Role of Scale Management in Carbon Capture, Utilisation and Storage (CCUS)
Authors: Heath Stephen , Mackay Eric , Jarrahian Khosro , Ishkov Oleg , Gusmao Patricia
Published: June 2024

Recent trends towards carbon net zero and the push to develop renewable energy as an alternative to fossil fuels have resulted in major environmental focus on de-carbonisation projects with an emphasis on carbon capture, utilisation, and storage (CCUS).

Both carbon capture and utilisation (CCU) and carbon capture and storage (CCS), capture carbon dioxide (CO2) from heavy industries and air, by direct air capture (DAC), and transport it to sites by rail, boat, or pipeline for injection into geological reservoirs for permanent storage and/or enhanced oil recovery (EOR).

A range of issues related to mineral scale deposition can be encountered that impact the efficiency of CO2 injection and utilisation/storage. These can include calcium carbonate deposition during CO2 capture in a calcium looping process, halite (NaCl) precipitation during supercritical dry CO2 injection and CO2 leakage due to the dissolution of carbonate cements and minerals in reservoir rocks which impact both cement and reservoir rock integrity. During CO2 utilisation for EOR, downhole and topside calcium carbonate deposition can occur in the production facilities.

Effective scale management strategies are essential to maintain a safe, sustainable, and efficient CCUS process. It will also be necessary to minimise CO2 footprint during the whole lifecycle by making it less energy demanding. Scale control can be based on continuous scale inhibitor injection or squeeze treatments. Additionally, for wellbore integrity and to better isolate the well from the formation, sulphate scale may deliberately be deposited to provide extra strength to cements impacted by contact with CO2. This intentional precipitation of sulphate minerals needs special attention to be paid to ensure precipitation in the correct location. This involves consideration of pumping equipment, well completion, and rock type as they impact the deployment process to control the location, rate and mass of sulphate mineral deposition.

This paper reviews the scale issues arising during CCUS including calcium carbonate deposition during carbon capture, halite and microbial induced calcium carbonate deposition during CO2 injection. Both conventional and unconventional scale management approaches are considered including treatments with and without scale inhibitors. The impact of well completion, cement type, and CO2 injection rates on CCUS and the selected scale management process are discussed. In addition, laboratory data for controlled barium sulphate (BaSO4) mineral scale deposition is presented coupled with field designs for CO2 utilisation through disposal in injection water in a calcareous sandstone and CO2 water alternating gas (WAG) injection in a carbonate reservoir.
Modelling of Halite Risk During CO2 Injection in a North Sea Aquifer
Authors: Ogundipe Oluwatosin Matthew , Mackay Eric James , Hatscher Stephan , Seri Gerardo
Published: June 2024

When dry supercritical CO2 is injected into a saline aquifer for storage, formation brine is displaced away from the wellbore. However, not all the brine is displaced. Residual brine is trapped behind the CO2 flooding front, and formation water may re-enter the near wellbore area under shut-in conditions. The water in this brine will evaporate, causing precipitation of salts. A numerical model is used to evaluate the risk of loss of injectivity in a North Sea candidate Carbon, Capture and Storage (CCS) aquifer.

The objectives of the study presented in this paper are to use a radial model of the near well zone in the candidate aquifer to:

Evaluate the risk of water evaporation due to CO2 injection under the field-specific conditions. Evaluate the risk for the reduction of porosity, permeability, and injectivity under a continuous injection scheme and a discontinuous injection scheme. Evaluate the threshold injection rate for salt precipitation to occur. Identify what is the worst halite scenario that can be predicted by modelling in this field case. In this case study, for all salinities evaluated, there is always some halite precipitated in the dry-out zone. However, For most of the sensitivities, there is insignificant injection damage arising. For a salinity of 1.2 M, the only sensitivities that led to observable loss of injectivity were when the injection flow rates were very low. Significant damage would require high salinity formation water (near saturation) or the combination of capillary and gravity forces to replenish brine in the dry-out zone very close to the well, such that replenishment flux would match evaporative flux. Maintaining a high injection flow rate reduces halite precipitation risk when viscous forces dominate.

This paper presents a methodology for evaluating the risk of halite precipitation during CO2 injection in aquifers and then uses that methodology to evaluate the risk for a specific North Sea CO2 storage project, identifying in this case minimal risk.
A Systematic Investigation into the Effect of Mutual Solvent Pre-Flushes on Scale Inhibitor Retention and Return
Authors: Singleton M. A. , Davis I. R.
Published: June 2024

Mutual solvents (MS) have been extensively applied prior to the main scale inhibitor (SI) treatment slug of squeeze treatments. Evidence from the field indicates that MS pre-flushes are beneficial, however, no systematic evaluation of their role has been performed. A series of core floods have been undertaken to elucidate the predominant mechanism that leads to these beneficial effects. Factors investigated included; presence/absence of an oil phase, type of oil phase present (mineral/crude oil), and core wettability (oil/water-wet). The objective was to investigate the impact of a specific mutual solvent (EGMBE) on the retention of DETPMP in cores that had been pre-flushed with MS prior to the main treatment and compare them to the corresponding core flood where no MS pre-flush had been applied ("No MS" case). In all the core floods, scale inhibitor injection and return profiles were evaluated and compared. Saturation changes throughout each flood were also monitored.

In all the water-wet cases, the return profiles for the flood with MS as a pre-flush were seen to be comparable to the "No MS" case; the mutual solvent showed no obvious improvement in SI adsorption and its return in the long post flush tail. However, it was found that applying a MS pre-flush to an oil-wet core significantly enhanced squeeze lifetime in comparison to its "No MS" counterpart.

The mutual solvent phase behaviour was also consistent with that for the water-wet cases, with it breaking through earlier than expected due to the presence of a residual mutual solvent phase that is stripped from the core throughout the injection stage.

A repeat experiment using the same materials did not show the expected improvement in SI return, however, examination of the crude oil used, indicated that it had changed significantly from the first experiments such that comparison to the initial "No MS" case was invalid – a different wetting state was achieved.

It is still our belief that the predominant mechanism by which MS beneficially enhances Squeeze lifetimes is through a wetting change from oil-wet to a more water-wet state, however further work is required to confirm this hypothesis.
Methodology to Evaluate Calcite Scale Inhibitors Under Turbulent Flow for Subsea Oilfield Production Applications
Authors: Pimentel Daniel , Kan Amy , Ye Yuqing , Wang Xin , Reiss Amit , Deng Guannan , Shen Yu-Yi , Leschied Cianna , Yao Tina , Tomson Mason
Published: June 2024

Calcite scale formation is a common issue in oilfield production from carbonate reservoirs. It causes losses in production and additional costs for prevention or even remediation of the deposits in the pipe walls and valves. Although the thermodynamics of the equilibrium and the use of scale inhibitors are well known, there are still questions about the kinetics of the deposition, and how it performs under different flow conditions. Following a literature review, there are a limited number of investigations regarding the assessment of calcite scale formation under high shear and turbulent flow regimes and there is good evidence for the increased risk of scale formation under turbulent flow. Actual test methods do not achieve the high shear stresses experienced in real field situations (high Reynolds number and shear stress). Based on that, testing scale inhibitor performance under turbulent conditions during qualification for field application can be game-changing to provide a more accurate dosage.
The Impact of Copolymers and Sulfonated Polymers on the Adsorption of Phosphonate Scale Inhibitors
Authors: Silva C. , McIver K. , Beteta A. , Sorbie K. , Johnson G.
Published: June 2024

Enhanced oil recovery (EOR) is critical to optimally producing existing reserves with a minimized carbon footprint. However, it is essential that the EOR process does not impact negatively on ongoing production chemistry treatments. The focus of this work is on the interactions between polymers and scale inhibitor in terms of adsorption. The adsorption of both is assessed using static adsorption tests to understand and analyze for any evidence of competitive adsorption between these species. The study also elucidates some features of the adsorption kinetics of the polymers used in this study.

Copolymers of acrylamide (AM) and acrylic acid (AA) have been the most prominent chemicals to be applied in polymer EOR, whereas sulfonated polymers containing acrylamide tertiary butyl sulfonic acid (ATBS) have been used for higher temperature and/or salinity conditions. This work was carried out in a field brine at a temperature of 31°C. The polymers consisted of AA-AM co-polymers (20-33 % AA) and AM-AA-ATBS ter-polymers (up to 15 mol% ATBS) and DETPMP as a common scale inhibitor. The adsorption levels of the polymers and DETPMP were measured both separately and in sequential addition experiments (at t = t1). The adsorption results in the open laboratory were compared with anaerobic results as they may better represent the field conditions – these experiments were conducted on North Sea water at 70°C as this is a common mid-range temperature at which DETPMP would be used.

While polymer adsorption levels of ~20 µg/g were measured after 24 hours, this increased continuously over 20-30 days for the AA-AM co polymers. The same trend was observed for the AM-AA-ATBS terpolymers – with adsorption at 24 hours of ~15 µg/g which again increased significantly over time. However, DETPMP adsorption when added into a pre-adsorbed layer of polymer showed a surprising behavior not reaching the equilibrium after ~ 72 hours regardless of the concentration tested, continuously increasing over time. To the author's knowledge, the DETPMP equilibrium has been reported to be around 24 hours or less.

These results are amongst the first observations of this type in the literature, and they highlight the need for the industry to develop a better understanding of the competitive interactions between scale inhibitor treatments and EOR polymers.
Development of a Novel Scale Inhibitor for Mineral Scaling Control Under Harsh Production Scenarios
Authors: Seufferlein Benjamin , Ruan Gedeng , Balsamo Vittoria , Jones Regan
Published: June 2024

Despite the progress made on the expansion of scale inhibitor (SI) product selection over the years, significant challenges due to mineral scaling persist. Though multiple scale inhibitor chemistries are available for mild to moderately severe conditions, there are limited scale inhibitor options that can effectively manage mineral scaling for harsh production environments. Therefore, the purpose of this study was to develop a novel scale inhibitor for severe production conditions such as those encountered in Pre-Salt formations.

A synthetic strategy was implemented to develop new scale inhibitors based on terpolymers. From the multiple polymers synthesized, the best candidates were pre-selected based on thermal stability, brine compatibility and static bottle tests at 70°C. Standard dynamic scale loop (DSL) tests were then conducted to evaluate the performance of the new polymers and their corresponding blends. Test conditions simulated various production environments for Pre-Salt development.

Our studies indicated that the novel scale inhibitor showed temperature stability for upwards of 60°C for 7 days and 4°C and 40°C for 30 days and compatibility with very high TDS brine (> 200k mg/L) even at elevated temperature (130⁰C). Furthermore, the final synthesized polymer showed the best stability and overall performance under these conditions compared to that of a commercial product and other synthesized products tested. It was also demonstrated that a synergistic effect between the final polymer and phosphonate in the final blend was responsible for further improved performance.