bluuebunny/crossref_metadata_2025 huggingface dataset:
Experimental Investigation of the Photochemical Production of Hydrocarbons in Warm Gas Giant Exoplanet Atmospheres
Authors: Fleury Benjamin , Benilan Yves , Venot Olivia , Henderson Bryana L. , Swain Mark , Gudipati Murthy S.
Published: October 2023

In warm (equilibrium temperature <1000 K) gas giant exoplanet atmospheres, the observation of trace species in abundances deviating from thermochemical equilibrium predictions could be used as an indicator of disequilibrium chemical processes, such as photochemistry. To predict which compounds could be used as such tracers, it is therefore essential to study how photochemical processes affect their abundances. For this purpose, we investigated experimentally the efficiency of the photochemical formation of hydrocarbons in gas mixtures representative of warm gas giant atmospheres as a function of the gas temperature at millibar pressures. We find that, compared to thermal reactions alone, photochemistry efficiently promotes, under the studied conditions, the formation of hydrocarbons, with the detection of acetylene, ethane, and propane, as well as carbon monoxide. Therefore, our results confirm the importance of photochemistry in exoplanet atmospheres as a disequilibrium process. Ethane is the major hydrocarbon formed in our experiments, in apparent contradiction with the prediction by thermo-photochemical models that acetylene should be the main hydrocarbon product. We also observe an evolution of the hydrocarbon production efficiency as a function of the temperature, a behavior not reproduced by a 0D thermo-photochemical model. Additional studies are necessary to definitively understand the origin of the differences between the experimental and modeling results and to infer the importance of our results for understanding hydrocarbon formation in warm gas giant exoplanet atmospheres. Finally, our work demonstrates the importance of experimental studies together with modeling studies to accurately interpret, understand, and predict observations of exoplanet atmospheres.
Radio Emission From a z = 10.1 Black Hole in UHZ1
Authors: Whalen Daniel J. , Latif Muhammad A. , Mezcua Mar
Published: October 2023

The recent discovery of a 4 × 107
M
⊙ black hole (BH) in UHZ1 at z = 10.3, just 450 Myr after the Big Bang, suggests that the seeds of the first quasars may have been direct-collapse BHs from the collapse of supermassive primordial stars at z ∼ 20. This object was identified in James Webb Space Telescope NIRcam and Chandra X-ray data, but recent studies suggest that radio emission from such a BH should also be visible to the Square Kilometer Array (SKA) and the next-generation Very Large Array (ngVLA). Here, we present estimates of radio flux densities for UHZ1 from 0.1 to 10 GHz, and find that SKA and ngVLA could detect it with integration times of 10–100 hr and just 1–10 hr, respectively. It may be possible to see this object with VLA now with longer integration times. The detection of radio emission from UHZ1 would be a first test of exciting new synergies between near-infrared and radio observatories that could open the era of z ∼ 5–15 quasar astronomy in the coming decade.
A 3D Numerical Study of Anisotropies in Supernova Remnants
Authors: Mandal Soham , Duffell Paul C. , Polin Abigail , Milisavljevic Dan
Published: October 2023

We develop a suite of 3D hydrodynamic models of supernova remnants (SNRs) expanding against the circumstellar medium (CSM). We study the Rayleigh–Taylor instability forming at the expansion interface by calculating an angular power spectrum for each of these models. The power spectra of young SNRs are seen to exhibit a dominant angular mode, which is a diagnostic of their ejecta density profile as found by previous studies. The steep scaling of power at smaller modes and the time evolution of the spectra are indicative of the absence of a turbulent cascade. Instead, as the time evolution of the spectra suggests, they may be governed by an angular mode-dependent net growth rate. We also study the impact of anisotropies in the ejecta and in the CSM on the power spectra of velocity and density. We confirm that perturbations in the density field (whether imposed on the ejecta or the CSM) do not influence the anisotropy of the remnant significantly unless they have a very large amplitude and form large-scale coherent structures. In any case, these clumps can only affect structures on large angular scales. The power spectrum on small angular scales is completely independent of the initial clumpiness and governed only by the growth and saturation of the Rayleigh–Taylor instability.
The Contribution and FIP Bias of Three Types of Materials inside ICMEs Associated with Different Flare Intensities
Authors: Fu Hui , Shi Xinzheng , Huang Zhenghua , Qi Youqian , Xia Lidong
Published: October 2023

The relationship between coronal mass ejections (CMEs) and flares is an important issue in solar and stellar physics. The studies on the origination and generation mechanisms of interplanetary CME (ICME) materials are crucial for understanding the connection between CMEs and flares. The materials inside ICMEs can be classified into three types, coming from corona directly (corona materials), heated by magnetic reconnection in corona (heated corona materials), and generated by chromospheric evaporation (chromospheric evaporation materials). Here the contribution and first ionization potential (FIP) bias of three types of materials inside ICMEs associated with different flare intensities are analyzed and compared. We find that the speeds and scales of near-Earth ICMEs both increase with flare intensities. The proportions of heated corona materials are nearly constant with flare intensities. The contributions of corona materials (chromospheric evaporation materials) are significantly decreased (increased) with flare intensities. More than two-thirds of materials are chromospheric evaporation materials for ICMEs associated with strong flares. The FIP bias of corona materials and heated corona materials is almost the same. The FIP bias of chromospheric evaporation materials is significantly higher than that of corona materials and heated corona materials, and it is increased with flare intensities. The above characteristics of FIP bias can be explained reasonably by the origination and generation mechanisms of three types of ICME materials. The present study demonstrates that the origination and generation mechanisms of ICME materials are significantly influenced by flare intensities. The reasons for the elevation of FIP bias, if ICMEs are regarded as a whole, are that the FIP bias of chromospheric evaporation materials is much higher, and the chromospheric evaporation materials contributed significantly to the ICMEs that are associated with strong flares.
The Sydney Basin in the Triassic—a review of the geology, flora and fauna, and ecosystems. The Narrabeen Group
Authors: McLean Graham
Published: October 2023

The aim of this report is to provide a framework within which future earth science researchers of the Sydney Basin in the Triassic Period can work to rapidly access information relevant to their particular field of study. Information on the geology, flora and fauna and ecosystems has been extracted and summarized from an extensive range of papers published from the late 1800s to present day. In many cases the taxonomic classification of specimens has changed over the years as more data has come to light. The history of these changes has been noted. This information is backed by specimen lists and illustrated by images of selected specimens sourced from the extensive palaeontological collection of the Australian Museum, augmented by additional images from the collection of the Geological Survey of New South Wales. The major Triassic geological structures of the Sydney Basin are the Narrabeen Group, the Hawkesbury Sandstone and the Wianamatta Group. This report provides a consolidated review of data presently available for the Narrabeen Group. Future reports will cover the Hawkesbury Sandstone and the Wianamatta Group in a similar manner.
New records of non-native Coleoptera in Italy
Authors: Ruzzier Enrico , Morin Lucio , Zugno Matteo , Tapparo Andrea , Bani Luciano , Di Giulio Andrea
Published: October 2023

In the last decades, climate change and globalisation have been exacerbating the introduction of non-native beetles worldwide. Due toits peculiar territory, climate and geographical position in the middle of the Mediterranean Basin, Italy is one of the European countries with the highest number of intercepted, adventive and established non-native beetles, some of which are invasive. In this perspective, producing new faunistic records and continuously updating reliable and easily accessible distributional data is a fundamental step in investigating and potentially preventing further species introduction.

The aim of this contribution is to report and discuss new faunistic records of non-native Coleoptera in Italy. For some species, new records enlarge the previously-known distribution (e.g. the ambrosia beetles Anisandrus maiche (Kurentzov, 1941) and Cnestus mutilatus (Blandford, 1894) or the click beetle Monocrepidius posticus (Eschscholtz, 1829)), while for others (e.g. the scarab beetle Archophileurus spinosus Dechambre, 2006), data confirm their establishment and highlight a possible expansion phase. The false powderpost beetles Ptilineurus marmoratus (Reitter, 1877) and the longhorn beetle Xylotrechus chinensis (Chevrolat, 1852) are two new additions to the Italian fauna, while the establishment of the monotomid beetle Monotoma americana Aubé 1837 is confirmed.
Les personnes déplacées internes au Mali face à la COVID-19 : une étude qualitative
Authors: AG Ahmed Mohamed Ali , Ly Birama Apho , Diarra Djeneba , Traore Fatoumata Bintou , Diarra Niélé Hawa , Toure Mohamed , Dembele Mahamadou , van de Put Willem , Gagnon Marie-Pierre , Doumbia Seydou
Published: October 2023

Introduction : Le Mali fait face depuis 2012 à une crise sécuritaire qui a entraîné des déplacements massifs des populations à laquelle s’est greffée la pandémie de la COVID-19. But de l’étude : Cette étude vise à explorer les représentations des personnes « déplacées internes » (PDIs), c’est-à-dire des personnes forcées de fuir leur lieu d’origine, sur l’existence de la COVID-19 ainsi que leurs connaissances sur ses signes, ses symptômes, les modes de transmission et les mesures de prévention. Méthodes : L’étude est qualitative et exploratoire. Des entretiens individuels et en groupes ont permis de collecter les données auprès de 52 PDIs de six sites de Bamako et Ségou. Tous les entretiens ont été enregistrés et transcrits. L’analyse de contenu thématique et le logiciel NVivo ont été utilisés. Résultats : Dans leur majorité, les PDIs croyaient en l’existence de la COVID-19 et avaient de bonnes connaissances sur les signes, les symptômes, les modes de transmission et les mesures de prévention contre la maladie. Toutefois, cela n’a pas été suffisant pour l’adoption des mesures de santé publique. Parmi ceux qui croient en son existence, certains pensent que c’est toutefois une maladie des blancs et des riches. Enfin, un groupe de participants croyait plutôt en des théories du complot selon lesquelles le gouvernement et les organisations humanitaires ne chercheraient qu’à gagner de l’argent à travers ces campagnes. Conclusions : Il s’agit à notre connaissance de la première étude au Mali explorant les représentations et les connaissances des PDIs sur la COVID-19. Ces résultats pourraient éclairer les politiques, stratégies et interventions de lutte contre la COVID-19 dans les sites PDI et dans la population générale.
Stochastic tumor-immune interaction model with external treatments and time delays: An optimal control problem
Authors: Alsakaji H. J. , Rihan F. A. , Udhayakumar K. , El Ktaibi F.
Published: October 2023

Herein, we discuss an optimal control problem (OC-P) of a stochastic delay differential model to describe the dynamics of tumor-immune interactions under stochastic white noises and external treatments. The required criteria for the existence of an ergodic stationary distribution and possible extinction of tumors are obtained through Lyapunov functional theory. A stochastic optimality system is developed to reduce tumor cells using some control variables. The study found that combining white noises and time delays greatly affected the dynamics of the tumor-immune interaction model. Based on numerical results, it can be shown which variables are optimal for controlling tumor growth and which controls are effective for reducing tumor growth. With some conditions, white noise reduces tumor cell growth in the optimality problem. Some numerical simulations are conducted to validate the main results.
A peanut and weed detection model used in fields based on BEM-YOLOv7-tiny
Authors: Hua Yong , Xu Hongzhen , Liu Jiaodi , Quan Longzhe , Wu Xiaoman , Chen Qingli
Published: October 2023

Due to the different weed characteristics in peanut fields at different weeding periods, there is an urgent need to study a general model of peanut and weed detection and identification applicable to different weeding periods in order to adapt to the development of mechanical intelligent weeding in fields. To this end, we propose a BEM-YOLOv7-tiny target detection model for peanuts and weeds identification and localization at different weeding periods to achieve mechanical intelligent weeding in peanut fields at different weeding periods. The ECA and MHSA modules were used to enhance the extraction of target features and the focus on predicted targets, respectively, the BiFPN module was used to enhance the feature transfer between network layers, and the SIoU loss function was used to increase the convergence speed and efficiency of model training and to improve the detection performance of the model in the field. The experimental results showed that the precision, recall, mAP and F1 values of the BEM-YOLOv7-tiny model were improved by 1.6%, 4.9%, 4.4% and 3.2% for weed targets and 1.0%, 2.4%, 2.2% and 1.7% for all targets compared with the original YOLOv7-tiny. The experimental results of positioning error show that the peanut positioning offset error detected by BEM-YOLOv7-tiny is less than 16 pixels, and the detection speed is 33.8 f/s, which meets the requirements of real-time seedling grass detection and positioning in the field. It provides preliminary technical support for intelligent mechanical weeding in peanut fields at different stages.
Gamification of Mathematics Teaching Materials: Its Validity, Practicality and Effectiveness
Authors: Lukman Hamidah Suryani , Agustiani Nur , Setiani Ana
Published: October 2023

Gamification is a strategy for involving students by incorporating game elements into the learning process to improve specific abilities, involving students, optimizing learning, supporting behavior change, and socializing. This study aims to develop gamification-based mathematics teaching materials specifically designed to improve students’ mathematical critical thinking and problem-solving abilities, as well as to test these products based on aspects of their validity, practicality, and effectiveness in the learning process in the classroom. The analysis, design, development, implementation, and evaluation (ADDIE) research and development model is used in this study. The sample used was 153 students from 3 junior high schools, namely Hayyatan Thoyyibah IT Middle School, Pelita YNH Middle School, and Tahfidz Qur’an Al-Fath Islamic Middle School, which were taken through the cluster random sampling technique. Data was collected through game validation sheets, FRISCO critical thinking ability test instruments, Krulik and Rudnick problem-solving ability test instruments, and student response sheets. Data were analyzed using a one-sample t-test, a two-sample paired t-test, and descriptive analysis. The results showed that gamification- based mathematics teaching materials met the valid, practical, and effective criteria for use in learning mathematics, significantly improving junior high school students’ problem-solving abilities and critical mathematical thinking with moderate improvement categories.
Correlation Between Cognitive Levels of Teachers’ Questions and Response Enthusiasm of Students
Authors: Yang Ning
Published: October 2023

Teachers’ questions and students’ responses are important interactive links in the educational process. In recent years, with the deepening of research on educational psychology, more and more studies have begun to pay attention to the influence of cognitive levels of teachers’ questions on students’ responses. However, although some studies have shown that the way teachers ask questions has a significant impact on the learning outcomes of students, there is no clear answer to the precise relationship between cognitive levels of teachers’ questions and response enthusiasm of students. In addition, existing research methods often rely too much on descriptive statistics and lack a deep understanding and exploration of correlation. This study aimed to explore the correlation between cognitive levels of teachers’ questions and response enthusiasm of students. A new method was first introduced to measure the response enthusiasm of students. Taking English teaching as an example, an evaluation model was constructed through factor analysis, and the evaluation results were analyzed through Kaiser-Meyer-Olkin (KMO) test and Bartlett’s Test of Sphericity. Then grey relational analysis was used to measure the correlation between cognitive levels of teachers’ questions and response enthusiasm of students. The results revealed that cognitive levels had a significant impact on the response enthusiasm. The findings of this study not only provide teachers with an effective strategy to enhance the learning participation of students, but also bring new theoretical knowledge and practical experience to the field of educational psychology.
Introduction
Authors: Plana Muriel , Escoubet Stéphane , Cervantes Xavier
Published: October 2023

Dans l’introduction à six mains de Kate Bush entre les arts, nous montrons d’abord en quoi cette publication collective devait être interdisciplinaire et se situer au croisement des arts concernés – musique, littérature, théâtre, danse, vidéo, cinéma – et des études culturelles et de genre. Nous y proposons également deux contextualisations indispensables de la figure de Kate Bush, l’une dans l’histoire des musiques actuelles, et l’autre dans la culture anglaise. Ainsi commençons-nous à éclairer, sur un mode synthétique, déjà pluriel, et avant même que les articles à suivre ne l’appréhendent plus en détail et en profondeur, le caractère singulièrement hybride, en termes d’arts, de valeurs et de cultures, de l’œuvre de cette autrice-compositrice-interprète contemporaine.
« Running Up That Hill » (1985) ad libitum : chorégraphie, dramaturgie, récritures
Authors: Vincent-Arnaud Nathalie
Published: October 2023

“Running Up That Hill”, qui est sans doute l’une des chansons les plus célèbres de Kate Bush, reflète les diverses facettes de l’artiste, illustrant notamment son goût prononcé pour des modes d’expression hybrides. L’intérêt artistique de cette œuvre repose tout autant sur la forme musicale, l’instrumentation et la voix que sur son esthétique chorégraphique et dramaturgique. Les multiples reprises et recréations du morceau, sur scène ou en vidéo, prennent souvent la forme de réécritures imaginatives et novatrices qui en exhibent la richesse originale et les potentialités évocatrices. Cet article examine la dimension inter-artistique de la version originale ainsi que de certaines de ses reprises, en en interrogeant la portée poétique et politique.
A Deal with God : analyse d’une hybridation gestuelle et musicale entre féminin et masculin
Authors: Boschiero Pauline
Published: October 2023

Cet article propose d’analyser le clip-vidéo « Running up that Hill », de l’album de Kate Bush, Hounds of Love, sorti en 1985. L’actualité pop de l’été 2022 a été marquée par ce que certains ont qualifié de « grand retour » de Kate Bush. Elle n’était, en réalité, jamais partie, comme le savent celles et ceux qui s’intéressent à elle et à son œuvre depuis le début. Quoi qu’il en soit, en figurant dans la bande originale de la quatrième saison de la série phénomène Stranger Things, le titre « Running up that Hill » a étendu et renouvelé son succès, notamment auprès de la jeune génération. Et c’est peut-être maintenant plus que jamais qu’une analyse esthétique et politique de ce morceau et de son vidéo-clip s’avère nécessaire. Le clip original de « Running up that Hill » a été mis en ligne sur YouTube le 15 janvier 2011 ; il aura fallu près de onze ans pour qu’il atteigne plus de cent millions de visionnages. L’extrait de la série, où le titre de Kate Bush joue un rôle déterminant, a été mis en ligne le 30 mai 2022 et cumule aujourd’hui plus de dix-huit millions de visionnages. Sans entrer dans une logique réactionnaire, nous essaierons de montrer dans cet article en quoi le vidéo-clip de 1985 est toujours d’actualité, notamment dans les champs d’études qui sont les nôtres, à savoir la danse et les études féministes et queer. L’analyse esthétique et politique de ce titre musical et de son clip-vidéo, dont le caractère romantique – au sens de la romance hétérosexuelle telle que l’inconscient collectif se la représente – a rarement été dépassé par la critique, nous permettra de voir dans quelle mesure Kate Bush invite à penser le concept d’écriture féminine développé par Hélène Cixous, sans tomber dans une féminité essentialiste.
Ultimate Strength Reliability Analysis Applied to the Design of Cement Sheaths in Oil Wells
Authors: Estrela Gabriela Alves , de Sousa Fernando Jorge Mendes , Lopes Guilherme Kronemberger , Gonzaga e Silva Ana Beatriz de Carvalho , de Andrade Henrique Conde Carvalho , Rocha José Marcelo Silva , Moreira Rafael Peralta Muniz , da Silva Ingrid Ezechiello
Published: October 2023

In offshore wells, cement sheaths are responsible for isolating the casing from the formation, protecting the latter from corrosion, and preventing fluid migrations that can cause severe blowouts in extreme situations.

The most usual methodology applied in the structural evaluation of cement sheaths is deterministic, where characteristic values are employed to model material properties and loads. At the end of the analysis, stresses (or any other derived parameter) are compared to allowable limits. Although this design methodology is relatively simple, it doesn't consider uncertainties regarding material properties and loading conditions. Moreover, no information is provided concerning how far the structure is from failure. These issues can only be addressed using a statistical approach.

In this way, this work aims to propose a reliability-based methodology to be applied to the design of cement sheaths. Using the FORM method and a structural analysis computer program (TENCIM-1D – Toledo Filho et al. 2020), failure probabilities can be easily accessed with low computational costs. These values can then be compared to target failure probabilities specified in offshore standards. In addition, the FORM method can also improve the design quality, as one of its subproducts – the derived importance factors – may help to identify the properties and parameters that most contribute to the obtained failure probabilities. Therefore, these properties and parameters are the ones that need to be better described statistically, either through experiments to survey physical properties or through field measurements.

The obtained results indicate the feasibility of the proposed methodology and the need to develop studies to determine the probability distributions, mean values and standard deviations of some physical properties and loads.
A Lean Electric Actuation System to Scale Up Carbon Storage Subsea
Authors: Kubacki M. , Orth A. , Hendrix G. , Silva J. P. Duarte da
Published: October 2023

Carbon Capture Utilization and Storage (CCUS) facilities are crucial to mitigate the global emissions in the next years in industrial scale. In the first CCUS pilot projects, the CO2 injection wells were developed using traditional hydraulic systems, resulting in overly complex systems with considerable CAPEX and OPEX as well as environmental risks. Available all-electric subsea control systems, designed for the oil and gas industry, are not suitable for upscaling the CCUS due to much higher CAPEX investment.

During the development of a new series of all-electric Subsea Valve Actuators (OTC- 28828-MS (ORTH and HENDRIX 2018), OTC-31083-MS (ORTH, HENDRIX, et al. 2021), OTC-32129-MS (ORTH, PLACIDO NETTO and HENDRIX 2022) & OTC-32346-MS (ORTH, HENDRIX, et al. 2023)) using the hydrostatic drive principle, the actuation technology was optimized to handle high loads while minimizing the power consumption during operation. Without the need for electric energy storage, these actuators provide a highly responsive safety function with SIL 3 based on field-proven springs. With a standardized design integrating industrial and automotive components, a lean production system is applied to ensure high quality and efficiency. The new SVA R2 is qualified to operate quarter-turn valves up to 270 Nm with less than 48 W and to hold position with a stand-by power less than 15 W.

This drive technology is now used in the development of a new generation of Subsea Electric Actuators for larger rotative and linear valves, all using the low power demand. Simulations indicate that an entire subsea tree could be operated with less than 385 W without applying an expensive subsea battery.

One of the biggest challenges for newborn energy transition sectors, such as CCUS, is that the industry would like to take the advantages of all-electric subsea control systems, but the associated costs is forcing them to apply conventional offshore hydraulic systems with their associated complexity and low productivity.

This paper shows how such a lean electric actuation system could dramatically simplify the subsea control architecture, reducing so the costs of the overall electric infrastructure needed for a safe and efficient Carbon Storage Subsea.
Creating Sustainable Value: An ESG Framework for the Petroleum Industry
Authors: Bandeira G. L. , Trindade D. N. , Sodario M. , Ferronatto G.
Published: October 2023

Efforts have been made on a global scale to reduce companies' impacts on the planet, people, and communities, prompting industries to reconsider their approaches to production and workforce management. However, several challenges and barriers impede businesses from fully embracing sustainable actions. One such obstacle is the creation of robust ESG planning. To address this issue, this research aims to develop a sustainability roadmap based on Environmental, Social, and Governance (ESG) strategies for a Norwegian Petroleum company. The programs are categorized into three pillars aligned with the triple bottom line and the Sustainable Development Goals (SDGs). To achieve this, a Steering Committee sponsors and oversees ten key workstreams (WS) derived from this strategy's construction.

The Environmental dimension encompasses the Energy Management & CO2 Emissions initiative, demonstrating the company's dedication to tackling climate change by curbing CO2 emissions and minimizing environmental impacts from its operations. Additionally, in the Waste Management program, the company strives to reduce waste generation and promote a circular economy approach. Moreover, the company actively contributes to the global decarbonization of Oil and Gas (O&G) production through the Low Carbon Solutions program.

As for the Social dimension, the Health & Safety program centers on creating a world-class performance organization, enhancing business competitiveness, and achieving a zero-incident vision. In the Talent Attraction & Retention program, people are acknowledged as the key to the company's success. The Diversity & Equality program showcases the company's commitment to non-discriminatory practices and equal opportunities. Through the Social Responsibility program, the company positively impacts local communities through educational initiatives.

Finally, in the Governance dimension, the Responsible Business Conduct program promotes zero tolerance for corruption. The Compliance Obligation for HSE program ensures strict adherence to HSE laws and regulations. In the Responsible Supply Chain program, suppliers are selected based on their adherence to high environmental, anti-corruption, and human rights standards. The study results inform recommendations to effectively accommodate an ESG strategy and roadmap, fostering optimal cohesion within the petroleum industry and integrating their strengths to positively impact the entire value chain and optimize the realization of organizational goals.
Free-Hanging Rigid Riser: Innovation X Market Solutions
Authors: Amorim Andre Ramiro , Tanscheit Peter , Bandeira Victor , Gomes Rodrigo Klim , Asgari Peyman
Published: October 2023

The exploration of oil and gas in ultra-deep waters is characterised by a series of technical challenges that have been gradually overcome with innovations applied to risers. When it comes to free-hanging rigid risers, the most common solution is the Steel Lazy Wave Riser (SLWR), which relies on installing buoyancy modules along an additional section of linepipe. Among the main challenges of the SLWR system are the additional cost and time for installation of the buoyancy modules, besides the risks related to installation and the need for additional riser length to accommodate the buoys. Alternative solutions have been conceived, such as the Gimbal Joint Riser (GJR), an articulated joint in-line with the riser that reduces the dynamic effect at the Touch Down Zone (TDZ), or the Residual Curvature Riser (RCR), which consists of deformed rigid riser sections that dissipates the energy transmitted from the hang-off to the Touch Down Point (TDP). All solutions have their own sweet spot depending on the harsh environmental conditions and on the floating unit type. This article aims to present the concept of the three solutions, comparing them in terms of cost and technical feasibility assuming a reference case. The three mentioned technologies address the problem of energy dissipation from the hang-off to the TDP in different ways, being independent solutions that use different resources and work based on distinct concepts. Assuming that installation time and total cost are two of the most relevant aspects of free-hanging rigid riser systems, these were the main criteria used for a comparison between the solutions, in addition to a line tension criterion, especially at the hang-off. The SLWR solution is established, and several results were published in literature. Such results are used as a reference for the present work. RCR is currently at Technology Readiness Level 2 (API/TRL-2), according to the API scale, with estimates based on numerical models and analytical calculations. The GJR is a solution at Technology Readiness Level 2 (API/TRL-3) and is currently undergoing the conclusion of technological qualification process. Therefore, for evaluation of GJR, calibrated numerical models are used according to the experimental tests already carried out in the qualification program. Results indicate that RCR and GJR present better performance in comparison with SLWR for operational and extreme cases with lower costs. SLWR is slightly better than competing technologies in terms of fatigue life, although, fatigue results of GJR and RCR also comply with operational requirement.
Submarine Optical Networks for Oil & Gas Operations
Authors: Fukuyama Y. , Harima J. , Hishiki K. , Trigo C. C. O. , Bordalo S. N. , Morooka C. K.
Published: October 2023

A set of modular network node elements with underwater coupling connectors was developed and tested in a laboratory water tank for use in submarine installations to provide integrated data acquisition, communication and control for offshore oil and gas production facilities, covering large areas of petroleum fields. The present work demonstrates the feasibility, usefulness and flexibility of this system. A simulation of a submarine network was set up with the main components submerged in the laboratory water tank connecting various nodes through optical cables and through the Internet in order to represent a scenario with FPSOs, land offices and submarine instrumentation. Physical connection, disconnection and reconnection operations were simulated in underwater conditions. The simulation of the operations demonstrated the reliability and practicality of wetmate connectors, which means faster and safer field operations. Exchanging signals between various nodes showed the potential for better integration and real time responses for technical management of offshore facilities. Tests with underwater instrumentation proved the usefulness of the system to monitor and control offshore wells and submarine facilities remotely. This also denotes the potential for permanent marine seismic grids applied to petroleum reservoirs. The current world of interconnected digital systems may push the offshore oil industry and marine resources exploitation enterprises into more efficient operations, higher revenue-cost ratios, increased safety and lightener environmental impacts. Submarine optical networks can be applied to advance offshore systems into the next generation of real time remote monitoring, decision making and action, as well as continuous and reliable intercommunication between ocean and land units, with less people exposed to dangerous conditions.
Computational Modelling of Wettability in Calcite-Oil-Water Systems
Authors: dos Santos Elias Siva , Vasconcelos Anaís Couto , Batista João Pedro Ribeiro , Melo Wesley Gomes Lima , Quintella Cristina Maria , De Carvalho Edgard Bacic , Ramos-de-Souza Elias
Published: October 2023

The injection of low-salinity water in oil reservoirs to improve the recovery of oil is effective in sandstones but its application in carbonates is still a matter of debate. To address the wettability of rock-brine-oil systems and the recovery of oil in a porous medium, a new integrated methodology comprising Molecular Dynamics (MD), Electrohydrodynamics (EHD) and Computational Fluid Dynamics (CFD) is developed and applied to a thin brine film on a carbonate rock that is bounded by an oil phase. Microscopic classical MD allows following the trajectories of the atoms and estimating the interaction energies and key parameters of the system. The mesoscopic EDH theory is applied to model a nanometric fluid layer through hydrodynamic equations and allows to obtain linear stability diagrams and to follow the nonlinear evolution of the system. The macroscopic CFD approach allows computing the flow of a biphasic fluid in a porous medium model designed from the images of scanning electron microscopy. The modelling allows us to improve the understanding of the physicochemical mechanisms behind the wettability of carbonate rocks and the flow of brine and oil phases. The rock wettability depends on several factors such as the balance between van der Waals, electrostatic and hydration forces. At reservoir conditions, the oil-water surface bears negative electric charges resulting from the oil polar groups located in the oil-brine interface, while the net concentration of electric charges at the rock-brine surface is positive due to the adsorption of positively charged ionic species. The van der Waals disjoining pressure is negative and that arising from hydration interactions is positive. In turn, the electrostatic disjoining pressure may be negative or positive. The rock surface tends to be more water-wet if it bears lower positive surface charge concentrations and more oil-wet otherwise. The approach of the two film surfaces is also regulated by the repulsive interactions originating from the hydration disjoining pressure. Recovery factors for more water-wet and more oil-wet systems are estimated.
Amplitude Friendly Imaging for Elastic Inversion: A Brazilian Offshore Case Study
Authors: Tavakoli B. , Whitehead S. , Trinh P. T. , Duquet B. , Rhodde S.
Published: October 2023

The Lapa field is situated in block BM-S-09 of the Santos Basin, with production having started some years ago. Here the pre-salt reservoir rocks are formed by the Aptian microbial carbonates of Itapema and Barra Velha Formations. More precisely, the target lays in a marginal high in a mantle-decoupled domain under extension constraint with transfer zone and local inversion. The hydrocarbon bearing reservoirs are oil-bearing showing a 4-way dip closure with one main porous sequence and a tight zone underneath. With the northeast part of the field already well developed, the context of a re-processing, imaging and inversion program is that of a planned increase in activity in the southwest part of the field. The southwest part of the field is complicated by rapidly changing thickness of overburden salt, that can have an impact on seismic products. The objective of the study is to get a seismic image more suitable for the interpretation of this structurally complex field, with reliable amplitude information for lithology and porosity characterization of Lapa reservoirs.

Amplitudes on seismic images can reveal important information regarding Petro-Elastic (PE) properties of geological formations. "Amplitude preservation" during seismic data processing and imaging is key for many exploration and development projects. Though in data processing steps (pre-migration) this is assured by direct evaluation of input and output data amplitudes, in the imaging process, amplitude preservation is a more effortful task. This is mainly due to the complications concerning imaging algorithms (e.g. the approximations for wave propagation regime) and geological complexity of the subsurface. For example, in complex media, such as deep salt structures, imaging algorithms based on asymptotic approximation of wave propagation (e.g. Kirchhoff and Beam migration) may not deliver very accurate images (from structural and amplitude perspectives). Therefore, for subsurface imaging of complex zones, industry tends toward more accurate algorithms such as Reverse Time Migration (RTM) and Least Squares (LS) imaging. Moreover, for elastic inversion based on or AVO/AVA principles (Amplitude Variation with respect to Offset/Angle) one needs to create offset/angle gathers in an amplitude friendly manner. In this study, we present our workflow to produce an amplitude friendly image with a high SNR (signal to noise ratio) suitable for elastic inversion.
Integrated Operations System: Implementation of a Truly Integrated Digital Oil Field and Development of Digital Twin
Authors: Balachandran P. Amal , Padmanabhan K. Vipin Krishna
Published: October 2023

The global oil and gas companies are aggressively adopting new digital technologies for process improvement, enhancing safety, reducing asset down time, and reducing overall cost of production to stay competitive. The Digital Oil Field (DOF) is the idea of digitalizing the oil field operations to improve production performance and collaboration both within and outside the organization. This paper discusses the giant leap taken by ONGC towards digitalization of one of its largest deep-water oil and gas field development – the KG-DWN-98/2. Integrated Operations System (IOPS) presently being implemented in ONGC, comprises of data collection and analytics modules, automation tools and collaboration enablers integrated together for streamlined decision-making, easily accessible expertise and safe collaborative co-location of essential personnel. Paper discusses the existing challenges being faced by ONGC in production optimization, asset maintenance and collaboration. IOPS system is proposed as a solution to overcome these challenges. With the help of IOPS, the concept of "Digital-Twin" is introduced in ONGC. The method of developing a digital twin for the entire field from reservoir to separator using existing industry proven software with limited customization are discussed in detail. The methodology adopted for acquiring field data, analysis of the acquired data and utilizing the business intelligence acquired for optimizing production and ultimately leading to business transformation is discussed. The use of advanced digital collaboration environments to effectively utilize the technical expertise located at various geographical locations to solve complex technical issues and provide quick resolution to business problems are discussed in detail. The usage of Big data for predictive analytics to move the decision making from a post event reactive approach to proactive responsive approach is briefly discussed. The functioning of different components of the IOPS system, the interconnection between various analytics modules, the flow of data between modules to form a digital twin of the field and the expected benefits of the system are discussed in detail. The system is expected to improve production uplift by 2 to 3% and reduce the overall OPEX cost by 10 to 20%. The system is expected to increase the Mean Time Between Failures (MTBF) and Mean Time to Repair (MTTR) of the critical assets by enabling Reliability Centered Maintenance (RCM).
On-The-Fly Mixing Skid Mounted Technology Allows Cost-Effective Stimulation Jobs on Rigs with Limited Deck Space in Brazil Offshore
Authors: Carrara M. , Colbert F. , Gachet R. , Garcia F. , Pedrosa H. , Junior A. , Rezende D. , deSouza J.
Published: October 2023

While pre salt carbonate reservoirs are the main source of hydrocarbon production in Brazil (Jardim et. Al 2020), offshore mature fields located on post salt and sandstone reservoirs are still relevant. Cost effective solutions and treatment optimization are required to maximize return on investment. This paper introduces a new method to perform these jobs economically and efficiently. An overview of the operations performed on Brazilian mature fields and contingency operations for pre-salt carbonate wells including methods, strategies and benefits are reviewed.

A compacted and versatile on-the-fly stimulation plant is deployed to perform acid stimulation jobs for sandstone and carbonate offshore formations. The use of this system provides the flexibility to mix several types of acidizing fluids in reduced areas, for both carbonates and sandstones, providing similar capabilities than a costly stimulation vessel, or an offshore rig with limited deck area. Concentrations of the stimulation chemicals are modified in real time, using various systems without stopping the pumping operation.

This compact on-the-fly stimulation method shows many benefits, saving rig time, allowing the pumping of several chemicals, and making feasible operations that were possible only with stimulation vessel due to limited deck space of the rig. In some scenarios, large acid volumes are pumped without the need of additional acid tanks with pre-mixed acid solutions. Higher pumping rates are attained, leading to large zonal coverage treatments and rig time savings. This method has been used very successfully in Brazil since 2018 using several acidizing systems, including HCl, Mud Acid, polymeric diversion system and other acid-based technologies. Over eleven wells were treated using this on-the-fly stimulation method. Such operations take a maximum of 15 days from mobilization until demobilization. Assembly skid mounted vessels can take double or triple of the time and can increase the costs three times, which can make some projects unfeasible. This solution is switchable for low-cost projects on mature wells and workovers.

The novelty is the introduction of a compact on-the-fly stimulation plant that provides with more efficient and cost-effective acid stimulation and pumping treatment allowing real-time acid concentration modification and the capability to use various acidizing technologies.
Barrier Management: Managing Operational Residual Risk from Offshore Drilling Units
Authors: Reis A. G. , Neves R. A. , Costa M. M.
Published: October 2023

Constellation, an oil development company operating drill ships and semisubmersible platforms in water depths of up to 12,000 feet, is innovating with dynamic real-time monitoring of operational safety barriers of rigs. The goal is to increase visualization and predictability of risks in drilling platforms. This technology is designed to enhance the safety of operations, reduce the risk of accidents, and provide greater visibility to the primary risk study of drilling platforms.

The technology facilitates continuous monitoring of the operational safety barriers of the rigs and provides real-time alerts if anomalies or failures are detected. Barrier monitoring integrates the risk study contained in the Heath Safety and Environmental Safety Case (HSE Safety Case) into daily operations, offering visualization of the integrity of safeguard barriers. This ensures assertiveness in decision-making to maintain safe operational continuity. Compared to the traditional method, where the risk study was a static snapshot at the moment the document was prepared, this innovative approach promotes a more integrated view.

Currently, in the HSE Safety Case of each maritime unit, there are 11 risk analyses of the Layer of Protection Analysis (LOPA) - Bow Tie type. This semi-quantitative risk assessment tool has its barriers monitored in real time. The utilization of this technology has resulted in improved safety measures and reduced risk exposure. Additionally, it has proven to save both time and money by allowing early identification of problems and facilitating preventive maintenance.

This system has potential for expanded application across various sectors, such as the petrochemical and mining industry. The real-time monitoring technology developed by Constellation is a game-changer, demonstrating the benefits of integrating technology with safety management. It offers a model that could be adopted widely to enhance operational safety and efficiency.