bluuebunny/crossref_metadata_2025 huggingface dataset:
Improving Performance of a DC-DC converter in a PV System using Wavelet-Discreet-Denoiser (WDD)
Authors: Abderahim Lanani , Yassine Beddiaf , Chrifi Alaoui Larbi
Published: May 2024

This article deals with the denoising of signals from sensors (current and voltage) in a photovoltaic conversion chain using wavelet theory. The idea is to reduce the noise as much as possible without distorting or losing the original signal information. To see the reliability of this proposed method, a comparative study between our proposed method (WDD) and the classic low-pass filter method was presented. The contribution in this work is the improvement of the DC-DC boost converter via the use of wavelet theory, however, that’s why we set two objectives: the first is to obtain reliable control of the DC-DC boost converter via the proposed WDD and the second to increase the overall system efficiency. The experimental results show a very great improvement in the quality of the signals of the proposed method compared to the classic method of filtering by low-pass filter.
Loss of Mitochondrial Tusc2/Fus1 Triggers a Brain Proinflammatory Microenvironment and Early Spatial Memory Impairment
Authors: Farris Tonie , Gonzalez Ochoa Salvador , Mohammed Muna , Rajakaruna Harshana , Tonello Jane , Kanagasabai Thanigaivelan , Korolkova Olga , Shimamoto Akiko , Ivanova Alla V , Shanker Anil
Published: May 2024

Brain pathological changes impair cognition early in disease etiology. There is an urgent need for understanding aging-linked mechanisms of early memory loss to develop therapeutic strategies and prevent the development of cognitive impairment. Tusc2, also named Fus1, is a mitochondrial-resident protein regulating Ca2+ fluxes to and from mitochondria impacting overall health. We reported that Tusc2-/- female mice develop chronic inflammation and age prematurely, causing age- and gender-dependent spatial memory deficits at 5 m.o. Therefore, we investigated Tusc2-dependent mechanisms of memory impairment in mice, comparing changes in resident and brain-infiltrating immune cells. Interestingly, Tusc2-/- female mice demonstrated proinflammatory increase in astrocytes, IFN-γ expression in CD4+T cells and Granzyme-B in CD8+T cells. We also found fewer FOXP3+ T-regulatory cells and Ly49G+ NK and Ly49G+ NKT cells in female Tusc2-/- brain, suggesting a weakened anti-inflammatory response. Moreover, Tusc2-/- hippocampi exhibited Tusc2- and sex-specific protein changes associated with brain plasticity, including mTOR activation, and Calbindin and CamKII dysregulation affecting intracellular Ca2+ dynamics. Overall, data suggest that dysregulation of Ca2+-dependent processes and proinflammatory brain microenvironment heighten in Tusc2-/- mice could underlie cognitive impairment. Thus, strategies to modulate the brain’s Tusc2-, Ca2+, and mitochondria-dependent pathways should be explored to improve cognitive health.
3-Dimension Epithelial Segmentation in Optical Coherence Tomography of the Oral Cavity Using Deep Learning
Authors: Hill Chloe , Malone Jeanie , Liu Kelly , Ng Samson Pak-Yan , MacAulay Calum , Poh Catherine , Lane Pierre
Published: May 2024

Purpose: To simplify the application of optical coherence tomography (OCT) for examination of subsurface morphology in the oral cavity and reduce barriers towards adoption of OCT as a biopsy guidance device. The aim of this work was to develop automated software tools for simplified analysis of the large volume of data collected during OCT. Methods: Imaging and corresponding histopathology were acquired in-clinic using a wide-field endoscopic OCT system. An annotated dataset (n = 294 images) from 60 patients (34 male, 26 female) was assembled to train four unique neural networks. A deep learning pipeline was built using convolutional and modified u-net models to detect the imaging field of view (network 1), detect artifacts (network 2), identify the tissue surface (network 3), and identify the presence and location of the basement membrane (network 4). Results: The area under the curve of the image and artifact detection networks was 1.00 and 0.94 respectively. The Dice similarity score for the surface and basement membrane segmentation networks was 0.98 and 0.83 respectively. Conclusion: Deep Learning (DL) techniques can identify the location and variations in the epithelial surface and basement membrane in OCT images of the oral mucosa. Segmentation results can be synthesized into accessible en face maps to allow easier visualization of changes.
Cancer-Induced Resting Sinus Tachycardia: An Overlooked Clinical Diagnosis
Authors: Sakellakis Minas , Reet Jashan , Kladas Michail , Hoge Gregory , Chalkias Athanasios , Radulovic Miroslav
Published: May 2024

Elevated resting heart rate is frequently observed in cancer patients, and is associated with increased mortality. Although specific chemotherapeutic agents can induce cardiotoxicity, the presence of sinus tachycardia in chemotherapy-naive patients suggests other factors likely contribute to this clinical presentation. Despite its prevalence, cancer-associated resting sinus tachycardia has not been fully recognized and comprehensively described as a separate clinical entity. Secondary effects of cancer, especially structural cardiac changes, secretory factors (inflammatory cytokines), and thromboembolic disease can cause resting tachycardia. Alternatively, rapid heart rate may reflect compensatory mechanisms responding to increased metabolic demands, raised cardiac output states, and even pain. Hence, cancer-associated tachycardia presents a clinical dilemma; acute life-threatening conditions (such as sepsis, pulmonary embolism, etc.) must be ruled out, but cancer itself can explain resting sinus tachycardia and more conservative management can avoid unnecessary testing, cost and patient stress. Furthermore, identification and management of cardiac conditions associated with cancer may improve survival and the quality of life of cancer patients.
Ground Management through Grazing in Rainfed Olive Orchards Provides High Olive Yields and Has Other Potential Benefits for Both the Soil and the Farmer
Authors: Dimande Paulo , Arrobas Margarida , Correia Carlos Manuel , Rodrigues Manuel Ângelo
Published: May 2024

Soil management in orchards can have several economic and environmental implications. In this study, three different soil management systems were compared in a dry-farmed olive grove: conventional tillage (Tillage), glyphosate-based herbicide (Herbicide) and Sheep Walking. The experiment lasted eleven years (2011-2022) and was carried out after a previous trial conducted on the same plot with the same treatments and duration (2001-2011). However, in the earlier trial, the Herbicide and Sheep Walking treatments switched positions in the plot, while the tillage treatment remained in its original place. The average total accumulated olive yields between 2011 and 2022 were 225.1, 230.9, and 245.0 kg tree–1 for the Sheep Walking, Tillage, and Herbicide treatments, respectively. However, no significant differences were observed between the treatments. The levels of total organic carbon in the soil, measured in samples collected in the last year of the study, were 41.3, 33.7, and 37.3 g kg–1, respectively for the same treatments. These findings indicated that the Tillage treatment exhibited lower soil organic matter content and reduced bioavailability of some nutrients, which raises concerns about its sustainability. On the contrary, employing Sheep Walking with an appropriate stocking rate, effectively controlling vegetation in the spring, ensured favourable soil properties and olive yields comparable to the other treatments. Moreover, the Sheep Walking approach provides supplementary advantages to the farmer, including revenue from the sale of animal products and the opportunity to transition to organic farming systems, which better align with the preferences of contemporary societies.
Purpureocillum lilacinum Plant Growth-Promoting Fungi
Authors: Rigobelo Everlon Cid , Nicodemo Daniel , Babalola Olubukola Oluranti , Desoignies Nicolas
Published: May 2024

Plants support numerous microorganisms within their tissues and the rhizosphere, and these microorganisms, known as the microbiota, can influence plant growth and health. Up to 40% of a plant's photosynthetic metabolism may be invested in the rhizosphere. The microbiota is considered an extra genome that can be modulated to meet plant needs. Researchers have identified a set of genes from these microorganisms, known as the microbiome, which can be manipulated to enhance plant growth and health, improve nutrient absorption, reduce the need for chemical fertilizers, increase resistance to pathogens and pests, and increase stress tolerance. In particular, fungi exhibit large genetic and metabolic diversity and are often used to promote plant growth. For example, the fungus Purpureocillum lilacinum has been employed primarily as a biocontrol agent to manage nematodes, but some studies have suggested that it may also promote plant growth by increasing the efficiency of the plant to absorb nutrients from the soil and provide phytohormones to plants. Therefore, the current review aims to summarize the existing literature on the use of this fungus in agriculture as nematodes control and discuss its potential as a plant growth promoter.
Muscle Mass and Muscle Strength in Non-Dialysis Dependent Chronic Kidney Disease Patients
Authors: Romejko Katarzyna , Szamotulska Katarzyna , Rymarz Aleksandra , Niemczyk Stanisław
Published: May 2024

Background Sarcopenia is a state with progressive and generalized loss of skeletal muscle mass and strength. It is a serious complication occurring in chronic kidney disease (CKD) patients which increases morbidity and mortality rate. Sarcopenia is diagnosed when loss of both compartments - muscle strength and skeletal muscle quality or quantity are present. However, there are still numerous patients, also with CKD, diagnosed as pre-sarcopenic individuals with low muscle strength and normal skeletal muscle quality or quantity and conversely, with correct muscle strength and decreased skeletal muscle mass, who are prone to develop sarcopenia in future life. It is crucial to examine numerous variables possibly associated with changes of skeletal muscle mass and muscle strength in terms of preventing the development of sarcopenia. The aim of the study was to investigate anthropometric and clinical correlates and sources of variation in both skeletal muscle mass and muscle strength in advanced stages of CKD. Methods The study sample consisted of 84 non-dialysis dependent patients of both sexes (including 45.2% of women) with eGFR < 45 ml/min/1.73m2: 26.2% with eGFR 30-44 mL/min/1.73 m2, 65.5% with eGFR 15-29 mL/min/1.73 m2 and 8.3% with eGFR < 15 mL/min/1.73 m2. Muscle strength was estimated by measuring hand grip strength (HGS) with the use of handheld hydraulic dynamometer. Muscle quantity was measured by bioimpedance spectroscopy using Body Composition Monitor. Appendicular skeletal muscle mass (ASM) was calculated according to Lin’s formula. Serum creatinine, urea, uric acid and albumin were measured. Results In bivariate analysis we found that ASM significantly and positively correlated with anthropometric variables such as body mass (r=0.903, p<0.001), NH weight (r=0.882, p<0.001), height (r=0.694, p<0.001), body mass index (BMI) (r=0.701, p<0.001), lean tissue mass (LTM) (r=0.664, p<0.001), lean tissue index (LTI) (r=0.433, p<0.001), fat mass (r=0.614, p<0.001) and fat tissue index (FTI) (r=0.449, p<0.001), and was negatively associated with clinical variable such as hydration status (p<0.001). HGS significantly and positively correlated with anthropometric parameters such as body mass (r=0.319, p=0.003), NH weight (r=0.315, p=0.004), height (r=0.666, p<0.001), LTM (r=0.490, p<0.001), LTI (r=0.238, p=0.029), and ASM (r=0.501, p<0.001), and was negatively associated with clinical variables like uric acid (p=0.039) and urea (p<0.001). After adjustment for age, sex and height, HGS remained significantly and negatively related with uric acid (β=-1.078, p=0.041) and hydration status (β=-0.805, p=0.042). Conclusions In CKD patients, ASM is determined mainly by anthropometric parameters but HGS - both by anthropometric and clinical variables specific for CKD.
Rupestonic Acid Derivative YZH-106 Promotes Lysosomal Degradation of HBV L- and M-HBsAg via Direct Interaction with PreS2 Domain
Authors: Liu Lanlan , Wang Haoyu , Liu Lulu , Cheng Fang , Aisa Haji Akber , Li Changfei , Meng Songdong
Published: May 2024

Hepatitis B surface antigen (HBsAg) is not only the biomarker of hepatitis B virus (HBV) infection and expression activity in hepatocytes, but also contributes to viral specific T cell exhaustion and HBV persistent infection. Therefore, anti-HBV therapies targeting HBsAg to achieve HBsAg loss are key approaches for HBV functional cure. In this study, we found that YZH-106, a rupestonic acid derivative, inhibited HBsAg secretion and viral replication. Further investigation demonstrated that YZH-106 promoted the lysosomal degradation of viral L- and M-HBs proteins. Mechanistic study by Biacore and docking analysis revealed that YZH-106 bound directly to PreS2 domain of L- and M-HBsAg, thereby blocking their entry to the endoplasmic reticulum (ER) and promoting their degradation in cytoplasm. Our work thereby provide basis for design of novel compound therapy to target HBsAg against HBV infection.
Characterization of a Multilayer Film Comprising Polybutylene Adipate Terephthalate and Cellulose Nanocrystals with High Barrier and Compostable Properties
Authors: Melendez-Rodriguez Beatriz , Prieto Cristina , Pardo-Figuerez Maria , Angulo Inmaculada , Bourbon Ana I. , Amado Isabel R. , Cerqueira Miguel A. , Pastrana Lorenzo M. , Hilliou Loic Hugues Gilles , Vicente António A. , Cabedo Luis , Lagaron Jose M.
Published: May 2024

In the present study, a multilayer high barrier thin blown film based on a polybutylene adipate terephthalate (PBAT) blend with polyhydroxyalkanoate (PHA), and composed of four layers, including a cellulose nanocrystals (CNC) barrier layer and an electrospun poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) hot-tack layer, was characterized in terms of surface roughness, surface tension, migration, mechanical and peel performance, barrier properties and disintegration rate. The results showed a material with a smooth surface. The overall migration test showed that the material was suitable for its use as a food contact layer. The addition of the CNC interlayer had a significant effect on the mechanical properties of the system, drastically reducing the elongation at break and, thus, the flexibility of the material. However, the material retained its elastic modulus and tensile strength. The CNC coating had a negative impact on the peeling strength, weakening the inherently strong interlayer adhesivity of the electrospun PHBV fibers. The multilayer had a good barrier to water vapor, and especially to oxygen, with its permeance reduced by up to a 90 % when the CNC layer was present. Finally, the monolayer blend film disintegrated in a period of less than 55 days in a laboratory-scale composting experiment, while the multilayer system disintegrated in 60 days. Overall, the multilayer system formed a fully compostable structure with great potential for use in food packaging applications.
Theorising the Hedging Strategy: National Interests, Objectives, and Mixed Foreign Policy Instruments
Authors: Gonzalez Pujol Ivan
Published: May 2024

Hedging is a comprehensive foreign policy strategy that mixes competitive and cooperative approaches and is used to manage competing national interests during conditions of uncertainty over the future distribution of power. However, the literature is characterised by a lack of consensus on the central features of hedging, which leads to contradictions in how the concept of hedging is
applied. First, this paper assesses the definition of hedging, identifies three rival approaches, and links the risks and opportunities of hedging with uncertainty over the future international distribution of power. Second, it discusses how the various interpretations of hedging have inspired different analytical models. Finally, it explains hedging as a theoretically intermediate and analytically mixed strategy. These claims are supported by studying the Asia-Pacific region, where hedging has become the dominant strategy for coping with the uncertainty surrounding the future distribution of power stemming from the rise of China.
Developing science magazine integrated with contextual teaching and learning approach based on local potential in talang siring beach, Indonesia
Authors: Fikriyah Aida , Ahied Mochammad , Qomaria Nur
Published: May 2024

One of exciting learning media is magazine in which students prefer to read this rather than books since magazine contains of various colorful images and appropriate information. Magazine can be developed by integrating with science learning approach in order that students can comprehend the concepts easier. This study aims at developing science magazine which is integrated with contextual teaching and learning approach according to the study findings in Talang Siring. The research included in a research and development study, using Borg and Gall model. The research was conducted on October to November 2022, which is located in Talang Siring Pamekasan, Indonesia by identifying ecosystem of beach and mangrove. Furthermore, the observation findings were arranged systematically in developing science magazine. Science magazine was evaluated by experts in concept and learning media. Findings indicated that the science magazine is valid with media validity score 93.5 and content validity score 91.6. Therefore, it is appropriate to implemented in science learning. Therefore, it can be concluded that science magazine is able to be used as learning media in science learning process
Identification of learning dificulties and factors causing learning difficulties in online lectures on basic biology concepts
Authors: Purbowati Dwi , Dewi Erlinda Rahma
Published: May 2024

This study aims to identifying learning difficulties from reviewing material and factors causing learning difficulties faced by Madrasah Ibtidaiyah Teacher Education study program in online lectures basic concepts of biology. The research particiants were 80 third-semester in 2021/2022 academic year. The research method used quantitative. The data collection technique in this study is a survey technique. The research instrument is a questionnaires were made to collect student data regarding learning difficulties in basic concepts of biology and the factors that cause student learning difficulties. Questionnaires were given to students via a google form. The data analyzed by descriptive statistics and used as reference data to determine the learning difficulties faced by students in the form of subject matter, internal and external factors causing learning difficulties. The results showed: a) In online lectures on basic concepts of biology, the material that students consider the most difficult is genetics, b) Internal factors that cause learning difficulties are lack of preparation before lectures, too much memorization, lack of self-motivation, physical tiredness, and laziness to read the material, c) External factors that cause students’ learning difficulties in basic biology concepts lectures, namely lectures resources and materials, lecture facilities, lecture strategies, lecture environment, and lecture hours.
Inquiry research trends through bibliometric analysis (2020-2023)
Authors: Lismaya Lilis , Wiyanto Wiyanto , Ridlo Saiful
Published: May 2024

This article aims to analyze the trend of Inquiry research through bibliometrics in the Google schoolar database from 2020 to 2023. The article consists of a total of 993 articles, then sorted into 788 suitable articles and analyzed. The method used in this research is article analysis using bibliometrics with the following stages: keyword search, initial search results, refining search results, compiling initial data, and data analysis. The results show that publications in scientific articles regarding Inquiry vary every year. Then, the description in Education research trends produces seven clusters, namely science process skills, science teacher, argument driven inquiry, framework, experience, critical thinking skills, and senior high school. The findings of this study are expected to help other researchers who are interested in studying and researching related to Inquiry research trends and recommend directions for further research
Empowering prospective teachers’ scientific and digital literacy through exploring-resuming integrated criticizing (ERIC) in biology classroom
Authors: Ramadani Shefa Dwijayanti , Lestari Ayu
Published: May 2024

Prospective Science teachers need well-developed science and digital literacy to help the process of thinking, learning, communicating, working together, and working with their creativity. Unfortunately, various studies show that students' abilities regarding these two types of literacy still need to improve, especially in first-year students. This study aims to (1) analyze the potential impact of the ERIC learning model with the lesson study-based TPACK framework on science and digital literacy and (2) analyze the contribution of lesson study implementation during ERIC learning to the professional development of educators. This study used a concurrent mixed method. In-depth analysis through lesson study was conducted during the implementation of the ERIC learning model in a quasi-experimental setting. The collected data was then analyzed using the ANCOVA test to reveal the difference in mean scores between the experimental and control classes. At the same time, the results of learning observations and reflection on the lesson study phase were analyzed qualitatively. The results showed that the ERIC learning model with the TPACK framework had a significant effect on scientific and digital literacy. In addition, implementing lesson study enables educators to become more aware of students' learning difficulties and needs and, therefore, develop deeper knowledge about learning requirements
Spherical shock waveform reconstruction by heterodyne interferometry
Authors: Hart Carl , Lyons Gregory , White Michael
Published: May 2024

The indirect measurement of shock waveforms by acousto-optic sensing requires a method to reconstruct the field from the projected data. Under the assumption of spherical symmetry, one approach is to reconstruct the field by the Abel inversion integral transform. When the acousto-optic sensing modality measures the change in optical phase difference time derivative, as for a heterodyne Mach–Zehnder interferometer, e.g., a laser Doppler vibrometer, the reconstructed field is the fluctuating refractive index time derivative. A technique is derived that reconstructs the fluctuating index directly by assuming plane wave propagation local to a probe beam. With synthetic data, this approach is compared to the Abel inversion integral transform and then applied to experimental data of laser-induced shockwaves. Time waveforms are reconstructed with greater accuracy except for the tail of the waveform that maps spatially to positions near a virtual origin. Furthermore, direct reconstruction of the fluctuating index field eliminates the required time integration and results in more accurate shock waveform peak values, rise times, and positive phase duration.
Strategies for Implementing Renewable Energy Initiatives Within the PSC Fiscal Frameworks: An Indonesian Case
Authors: Putra Iswahyudi Sondi , Hariandy Pityt Puty
Published: May 2024

Renewable energy initiatives are of utmost importance on a worldwide level, as they address environmental concerns and promote sustainable development. Customizing these activities to the unique characteristics of each country is crucial for attaining success. Developed nations place a higher importance on technological advancements and the integration of power grids, whereas undeveloped countries prioritize making electricity accessible to all and implementing decentralized energy systems. The importance lies in the reduction of carbon emissions, ensuring energy independence, and fostering economic growth. Countries should use their unique resources, such as solar, wind, or hydropower, in order to maximize their impact. The implementation of various renewable energy solutions demonstrates the growing international collaboration and demonstrates a shared commitment to a greener and more resilient future.

Indonesia, adopting a fiscal framework known as a Production Sharing Contract, aims to achieve net zero emissions by the year 2060. The energy sector, which is responsible for the highest level of emissions, including those from oil and gas, has implemented a program aimed at reducing these emissions. The government entity responsible for managing the PSC contract, SKK Migas, has a program focused on renewable energy efforts and low-carbon initiatives. This program is coordinated with oil and gas companies. The approval of the program and budget for low-carbon initiatives provided by SKK Migas provides a positive signal for investment by oil and gas companies, where they receive certainty that the low-carbon initiatives program will be reimbursed by the Indonesian government through a cost recovery mechanism.
Three-Pressure Prediction Method for Formation Based on Xgboost-gnn Hybrid Model
Authors: Zou Lu , Tang Ming , He Shiming , Wang Hanchang , Guo Xinyu
Published: May 2024

Accurate prediction of Three-Pressure data in geological formations can assist in determining drilling fluid design, wellbore stability assessment, and optimization of drilling parameters, thereby reducing the probability of drilling risks. Conventional methods for predicting triplet pressure in geological formations often involve complex calculations, numerous empirical parameters, low prediction accuracy, limited universality, and a certain degree of lag. Therefore, there is an urgent need for new methods that are efficient, simple, and accurate in predicting triplet pressure in geological formations. To address the aforementioned issues, this study focuses on the Penglai gas area in the Sichuan Basin. By employing the XGBoost algorithm, three well logging parameters, namely acoustic time difference, compensating density, and natural gamma, are selected to classify the strata into two types: clastic rocks and carbonate rocks. Additionally, using 11 well logging and drilling parameters, including well depth, acoustic time difference, compensating density, natural gamma, drilling time, drilling pressure, and torque, a graph neural network (GNN) is applied to capture the spatial geological features of the strata. Separate GNN prediction models are established for both clastic rocks and carbonate rocks, and the predicted results are compared and validated against field-measured data. The results indicate that the XGBoost algorithm achieves a classification accuracy of 94.31% and an AUC of 0.99. The GNN prediction models exhibit good accuracy and stability. When compared with the field-measured data, the clastic rock model shows an average MAPE of 3.963% and an average R2 value of 0.869 for the testing set, while the carbonate rock model shows an average MAPE of 1.681% and an average R2 value of 0.885 for the testing set. Compared with conventional rock mechanics three-layer pressure prediction methods such as the Eaton method, the XGBoost-GNN algorithm demonstrates higher accuracy, precision, stability, and more accurate data for predicting layer positions. By utilizing the XGBoost-GNN algorithm, this study proposes a classification-first, prediction-second methodology, which effectively captures the spatial and geological features of the strata by modeling the graph structure. This approach provides more accurate prediction results and supports drilling engineering design and safe and efficient drilling.
Ocean Bottom Nodes Seismic Survey Evaluation in the Central Gulf of Suez a Revival of the Exploration Portfolio in a Mature Basin
Authors: Abouhadid H. , Maged M. , Gaber T. , Raafat R. , Morsy A.
Published: May 2024

The Gulf of Suez (GOS) is located in northeast Egypt and represents the northern extension of the Red Sea and is one of the most prolific oil provinces in Egypt, (fig. 1). This basin is an Oligo-Miocene rift. Structurally, it is a complex basin where rotated fault blocks represent the main trapping style. The exploration history of the basin dates back to the end of the 19th century when the first commercial oil was discovered in 1908 (Gemsa Oil Field). There are more than 170 fields and 3000 wells in the basin. Most of the fields are mature and in their brown stage. The seismic data in the GOS is challenging and the quality of the data is generally sub-optimum to map reservoirs in a complex structural setting, especially in areas far from well control. This paper aims to showcase how the recent technology of the Ocean Bottom Nodes (OBN) seismic technology yields superior data quality compared to the legacy datasets. It resolved to a far extent the problems that the operators face in the acquisition and processing of conventional towed streamer 3D seismic data in the area.
Operations-Maintenance Synergy at Petroleum Facilities for Enhanced Productivity, Asset Integrity and Occupational Harmony
Authors: Bassey B. O.
Published: May 2024

Operations personnel in the petroleum and other fast-paced industries are primarily concerned with optimizing productivity while maintenance teams focus on asset integrity. These seemingly conflicting objectives generate occupational conflicts in many process facilities, threatening process and human safety. This paper examines the nature of these conflicts, their sources and consequences using an offshore petroleum transportation and storage facility as case study, discusses solutions adopted and highlights significant outcomes. As similar problems occur in facilities around the globe, the presentation intends to share learnings from this case to a global audience and stimulate useful debates. To foster occupational harmony and a balancing act, toolbox and management meetings were held. An operations-maintenance synergy (OMS) model was created, with an interface coordinator from each department. Field data from facility inspections, post installation surveys and parallel condition monitoring reports were used to evaluate OMS performance. These fed quarterly gap analyses for process equipment and safety critical devices across two terminals, two jetties, two tanker vessels and seven retail stations. Operational bottlenecks such as unplanned shutdowns and turnaround time were also assessed for asset integrity, productivity and occupational performance over a 5-year period. HSE and managerial metrics such as staff motivation, interpersonal relationships and turnover were identified as human factors critical to the OMS model efficiency. Production records are analyzed for both periods to assess the workability of the model. Results indicated improved operational excellence, maintenance excellence and safety management. These were demonstrated through reduced audit queries, non-productive time, unplanned shutdowns, customer complaints, staff turnover rate and avoidable costs such as demurrage. These are critically analyzed, stating upgrade plans for future operations. The findings demonstrate that various organizational functions can synergize amicably with mutual understanding, acknowledging other as partners in progress rather than rivals. Lessons learnt and recommendations should contribute towards addressing non-productive time, asset deterioration, workplace conflicts, process safety accidents and other avoidable negatives in process industries upon diligent application. The paper demonstrates how local content, in-house human capacity and existing systems could be managed for business growth and conducive working environment.
Unlocking Innovation Potential: A Pragmatic Approach to Overcoming Barriers and Fostering Collaboration
Authors: Zubari H. , Sherman S.
Published: May 2024

This paper outlines a comprehensive methodology for embedding innovation within the operational fabric of a smaller international oil and gas company, through the deployment of a holistic innovation framework. This framework is designed to enhance the generation, evaluation, and implementation of innovative ideas across various levels of the organization. By embracing the distributive essence of innovation, the company has adopted a dual-faceted strategy: internally, through the establishment of an innovation platform that encourages, empowers, and rewards creative and cost-efficient idea generation; and externally, by cultivating a vibrant ecosystem of partnerships that harnesses sector-specific knowledge and expertise. Additionally, a meticulous stage-gated process is employed to ensure the rigorous assessment and development of ideas, thereby streamlining the path from conception to execution.

The innovation platform stands as a pivotal mechanism for spurring idea generation and facilitating the exchange of knowledge across all business units, effectively dismantling traditional barriers to innovation, including geographical constraints. It empowers frontline staff to actively participate in idea submission, promoting a grassroots approach to innovation and resulting in a richer diversity of ideas that navigate both psychological barriers and issues of superiority. This approach has successfully dismantled siloed operations, cultivating a deeply collaborative culture that spreads innovative thinking throughout the organization. Moreover, the paper delves into the critical role of boundary spanners in weaving innovation into the organizational culture, acting as conduits for cross-functional collaboration and ensuring the seamless integration of innovative practices. Through this pragmatic strategy, the company has not only surmounted internal barriers but has also positioned itself to dynamically respond to external challenges, securing its growth and competitive stance in the global oil and gas industry.
Characteristics of Meandering Channels Found in Mishrif Shallow Water Carbonates Deposited in South Mesopotamian Basin, Iraq and their Importance for a Giant Field Development
Authors: Qiu Maojun , Aidarbayev Sanat , Xia Fenglin
Published: May 2024

The recognition of channels and their subsequent comprehensive analysis are pivotal aspects in the deployment of wells within a green field, and for effectively monitoring the performance of the reservoir. Nonetheless, the identification of channels within a carbonate reservoir often proves to be a challenging task through the sole utilization of seismic attributes. Furthermore, petrophysical properties are frequently deduced from a single source of data, which may lead to incomplete insights. It is of paramount importance to address the intricate shape and property of carbonate channels by employing a synergistic approach that integrates data from multiple sources and employs diverse approaches.

Within the scope of this research, a series of seismic attributes were employed to effectively delineate carbonate channels. A RGB color blending technology trials resulted in successful detection of multiple meandering bodies. The porosity measured from wireline logs and core analyses findings confirmed the presence of reservoir quality grainstone/floatstone fabrics within the incision geometry highlighted by the seismic attribute. Conversely, the depositional facies lying outside these channels exhibit substantial mudstone and wackestone intertidal origin, indicative of low reservoir quality. The integration of seismic and well data facilitated the quantification of channel dimensions, revealing the following parameters: width approximately 1 km, height ranging from 7 to 15 m, and lateral length 15 km at least. The integrated core analysis and description reveal that erosional surfaces with hardgrounds, coupled with an abundance of burrows, serve as the primary indicators of the channel incision base. The findings were incorporated into the regional and local sequence stratigraphic context, shedding light on how these channels formed in response to sea-level fluctuations. The unification of these critical properties and channel evolution interpretations facilitated the identification of analogues currently present in Arabian Plate.

Similar to fluvial channels, tidal channels are crucial for optimizing well placement, improving hydrocarbon reserve accuracy, and identifying preferred flow directions during FDP execution. According to few regional studies, Mishrif channels appear to be widely distributed throughout the Mesopotamian basin and beyond. While fluvial channels have a well-established history of application in reservoir characterization, the application of carbonate channels in field development is quite scarce, almost absent. Hence, companies involved in the development of the Mishrif or equivalent formations, particularly those in proximity to our study area, stand to benefit significantly from detecting and characterizing these channels. This information can play a crucial role in decision-making for hydrocarbon exploration and production.
Subsurface and Operational Challenges in a Successful Microfrac Operation and Remedial Solutions – Observations from Recent Experiences in Tight Unconventional Reservoirs
Authors: Sen Souvik , Chakrabarti Prajit , Franquet Javier A.
Published: May 2024

In this study, we discuss the subsurface and operational challenges and effective remedial solutions for the wireline straddle packer microfrac operations to achieve successful breakdown and conclusive closure pressure, based on our recent experiences from the recently concluded microfrac campaign in the challenging Triassic and Cambrian unconventional reservoirs of Northern Africa. We share our experiences from the deeper clastic and carbonate targets which are tight, extremely strong, and exhibit a very high breakdown pressure gradient of up to 1.16 psi/ft. In case of breakdown pressure elevated by external factors (effect of mud filtrates etc.), the pump-out method facilitated the formation breakdown. The majority of the microfrac tests in these tight formations showed the proven benefit of multiple rapid loading and unloading cycles by injection (hole pressurization) and pump-out (hole depressurization) in inducing near-wellbore fatigue to effectively weaken the formation before achieving successful breakdown. The effect of near-wellbore poroelasticity was also observed, resulting in increasing fracture reopening and closure pressures in the consecutive microfrac test cycles; the pump-out technique was also effective in eliminating such effects. The tight unconventional reservoirs exhibited a low leak-off coefficient resulting in poor natural fall-off pressure decline response resulting in an overestimation of closure gradient. Therefore, controlled flowback by a small volume pump was adopted to achieve induced closure and conclusive Shmin estimates.
Scaling Field and Experimental Data Using Machine Learning Approaches to Evaluate Oilwell Cement Degradation, Stability and Integrity for CCUS Applications
Authors: Abraham J. J. , Devers C. , Teodoriu C. , Amani M.
Published: May 2024

Carbon Capture, Utilization and Storage (CCUS) processes are increasingly being utilized as a viable solution for carbon removal and meet the goal of net-zero carbon emissions by 2050. Captured carbon dioxide (CO2) is stored deep underground – typically in depleted oil or gas (O&G) wells - utilizing technologies and methods currently employed by the energy industry. However, there are certain ongoing well integrity challenges that would need to be addressed – especially those relating to the cement layer. Cement present in wells used for CCUS applications – including old or abandoned wells - need to ensure zonal isolation, be resistant to deterioration, corrosion, or gas migration, as well as be suited for adverse downhole conditions.

Oilwell cement present in existing or abandoned O&G assets have been exposed to a wide range of downhole conditions throughout their lifecycle. It is generally very difficult to determine the mechanical properties and physical condition of the cement downhole and a decline in these properties is expected over time. Experimental evaluations have shown that temperature plays a role in the setting and maturity of the cement, and in CCUS wells, corrosive factors are a major concern due to the acidic environment produced at the CO2 injection zone. These can significantly affect cement mechanical properties such as the Uniaxial Compressive Strength (UCS). Evaluations have shown Temperature or Acoustic Logs can be used to determine downhole properties which can then be correlated to the behavior of cements and the change in their mechanical properties over time using machine learning algorithms.

Laboratory evaluations showed varying mechanical properties for oilwell cement at different temperatures and degradation over time. Overall, Class G cements developed the highest stress failure resistance, followed by Class H cements. Higher temperatures accelerated the setting time of all cement samples due to rapid dehydration. However, this in turn reduced the peak UCS developed, indicating a lower stress failure criterion. UCS also showed a direct relationship to acoustic data which can be utilized to evaluate mature and abandoned wells for their integrity. When modeled using supervised machine learning algorithms, field temperature data and acoustic data can reliably predict the mechanical properties of cements over time. An artificial neural network model, and two tree based models were developed, which showed good correlation in predicting compressive strength of downhole cements.

Properly understanding the behavior of oilwell cement and the evolution of their mechanical properties is critical to ensure safe storage. Data driven algorithms which can correlate the dynamic mechanical properties of cement to the temperature gradient and acoustic logs can help reliability predict the integrity of the cement layer over time especially for CCUS applications.
Vibroacoustic Technology: Revolutionizing Pipeline Integrity Monitoring for Enhanced Performance
Authors: Gomes A. P. , Marino M. , del Giudice S.
Published: May 2024

The aim of this work is to present a versatile and robust vibroacoustic pipeline integrity monitoring technology, easily retrofittable to existing assets, capable of real-time detection and localization of leaks and Third-Party Interference (TPI). Additionally, the technology can offer features such as PIG tracking, assessment of valve-sealing quality, pressure tests, and more.

Top-class vibroacoustic sensor blocks are strategically positioned several kilometers apart along the pipeline. They effectively capture vibroacoustic waves generated by leaks and TPI events as they propagate through the pipeline and the surrounding fluid, taking advantage of the pipeline’s efficient waveguide properties. The acquired data is then transmitted to dedicated processing servers, triggering alarms as necessary. For leak detection, the system relies on an Advanced-Negative Pressure Wave, while the localization of both leaks and TPI events employs the TDOA method (Time Difference of Arrival). Sophisticated and patented algorithms are implemented to address noise removal, detection, and localization, resulting in a substantial reduction in the false alarm rate.

The Vibroacoustic Technology outlined in this work is presently deployed and operational on numerous pipelines globally, actively surveilling thousands of pipeline kilometers. The system has demonstrated its effectiveness in rapidly detecting and precisely localizing both spillage and impact events. Moreover, the system can identify and localize any internal events interacting with the pipeline, opening possibilities for various applications to monitor the asset. The sensor blocks are installed in hydraulic derivations along the pipeline tens of kilometers apart. These blocks transmit real-time data to a processing server, requiring less than 20 kbit/s and consuming less than 20 W of power. After a brief installation campaign, the detection system is calibrated, and the versatility of Vibroacoustic Technology is evident in its integration for diverse integrity management requirements. This work displays real use cases where the technology has excelled, detecting leaks, excavations, PIG tracking (in real time or after the PIG is lost inside the pipe), assessing inline valve sealing quality, identifying corrosion micro-vents, and accurately localizing existing leaks during pressure tests. The demonstrated results emphasize the efficacy and adaptability of Vibroacoustic Technology across several applications.

The novelty feature of this pipeline management and integrity tool lies in its unparalleled flexibility in deployment options. This achievement allows the system to be installed across a diverse range of challenging scenarios, in liquid or gas pipelines, ensuring outstanding performance in each instance.
Novel Approach to Stimulation Design Optimization for Ultra-Deep, 200°C Temperature Formations: A Case Study in Kunteyi Block
Authors: Hou Tengfei , Lin Hai , Wu Xi , Wang Xiaolu , Li Zhanchun , Zhang Shiling , Feng Shengli , Zhang Yang , Liu Yong , Shang Litao , Bai Haoli
Published: May 2024

The kunteyi Block, a domestic gas field, poses unique challenges with its ultra-deep, 392°F high-temperature conditions. These extreme environments significantly challenge the safety and efficiency of well testing and stimulation. The block faces issues such as:1) Difficulty in reservoir coring and low accuracy in mechanical parameter interpretation from conventional logging data; 2) Challenges in fracture initiation under pressure constraints in ultra-deep (20,964 ft TVD), high-stress, high-angle wells; 3) Lack of experience in fracturing operations for ultra-deep, high-angle wells at 392°F.

This paper presents a design methodology and process tailored for ultra-deep, high-temperature, high-angle wells. It begins with cutting test technology for in-depth rock mechanics testing, followed by an innovative mechanical specific energy calculation method, factoring in actual drilling bit selection. This approach, combined with rock mechanics parameters, facilitates the identification of optimal cluster locations. Key construction parameters like inter-stage spacing, perforation cluster number and hole count, measure displacement, and fluid volume were further refined through three-dimensional fracture expansion modeling. Moreover, for a suspected aquifer 30 feet below the first section, a targeted low-displacement, small-scale acidification process was implemented.

The results demonstrate that this method effectively quantifies the rock mechanical parameters of the Kunteyi Block. The optimized perforation locations achieved lower breakdown pressures of 13,778 psi; an 8.5% reduction compared to neighboring wells at 15,055 psi. The high-angle wells, segmented into four stages with differentiated fluid scales ranging from 56,504 to 63,566 cubic feet and a pump rate increase from 18.9 bpm to 62.9 bpm, enabled efficient fracture initiation. The implementation of small-displacement acidification effectively prevented communication with the water layer, thus enhancing the project's feasibility.

This paper validates the effectiveness of cluster location enhancement using cutting tests and mechanical specific energy methods. These findings offer valuable insights and practical experience for the efficient stimulation of ultra-deep, high-temperature, high-angle wells.