A Transient Flow Model for Investigating Parameters Affecting Kick Behavior in OBM for HPHT Wells and Backpressure MPD Systems

2018 ◽  
Author(s):  
Dalila Gomes ◽  
Marius S. Nilsen ◽  
Johnny Frøyen ◽  
Knut Steinar Bjørkevoll ◽  
Antonio C. V. M. Lage ◽  
...  
Keyword(s):  
Volume Expansion ◽  
Transient Flow ◽  
Control Device ◽  
Special Focus ◽  
Transient Model ◽  
Free Gas ◽  
Managed Pressure Drilling ◽  
Drilling Operations ◽  
Transient Models ◽  
The Impact

Gas kicks can occur during conventional drilling operations, in which case the well has to be shut in and the kick circulated safely out of the system. In back pressure managed pressure drilling (MPD) systems, one can tolerate minor influx sizes before the well is shut in. However, when using oil based mud, solubility issues can complicate the picture making both kick detection and safe handling of kicks more complex. For sufficient large pressures the solubility can be infinite. A kick can also be taken undetected and reach the riser before the free gas suddenly emerge with a corresponding volume expansion that can unload the riser. Managed pressure drilling can be based on having a rotary control device on top of the riser, which makes it possible to add a backpressure on top to dampen the volume expansion, but possibly also change the depth where free gas emerges. It has been shown in another paper how one can use transient models to predict what kind of surface pressure is needed to maintain a constant bottomhole pressure when free gas emerge. In this paper, a fully transient model developed for a research cooperation between a research institute and Academia will be presented. The model includes behavior of kicks in oil based mud and solubility issues. The model will be used to study the behavior of kicks in riser when considering a backpressure MPD system with special focus on MPD from floaters. One objective will be to show how the results can be impacted by accuracy in the calculation method due to the amount of numerical diffusion present. Another objective will be to show how the PVT model adopted can affect the results. In addition, one will study the impact on results when varying physical input parameters like kick size, magnitude of pore pressure and the geometry of the riser.

Riser gas risk mitigation with advanced flow detection and managed pressure drilling technologies in deepwater operations in Australia

2014 ◽  
Vol 54 (1) ◽  
pp. 23
Author(s):  
Julmar Shaun Sadicon Toralde ◽  
Chad Henry Wuest ◽  
Robert DeGasperis
Keyword(s):  
Risk Mitigation ◽  
Control Device ◽  
Asia Pacific ◽  
Well Control ◽  
Alternative Approach ◽  
Managed Pressure Drilling ◽  
Drilling Operations ◽  
Drilling System ◽  
Flow Detection ◽  
And Control

The threat of riser gas in deepwater drilling operations is real. Studies show that gas kicks unintentionally entrained in oil-based mud in deepwater are unlikely to break out of solution until they are above the subsea blowout preventers (BOPs). The rig diverter is conventionally used to vent riser gas with minimal control and considerable risk and environmental impact involved. Reactive riser gas systems provide a riser gas handling (RGH) joint that is composed of a retrofitted annular BOP and a flow spool with hoses installed on top of the rig marine riser. A proactive, alternative approach to riser gas handling, called riser gas risk mitigation, is proposed by using managed pressure drilling (MPD) equipment. MPD involves the use of a rotating control device (RCD) to create a closed and pressurisable drilling system where flow out of the well is diverted to an automated MPD choke manifold with a high-resolution mass flow meter that increases the sensitivity and reaction time of the system to kicks, losses and other unwanted drilling events. Experiments and field deployments have shown that the deepwater MPD system can detect a gas influx before it dissolves in oil-based mud, allowing for management of the same using conventional well control methods. Since the MPD system has already closed the well in, automatic diversion and control of gas in the riser is also possible, if required. This paper presents experience gained from deepwater MPD operations in the Asia-Pacific to illustrate this, and possible deployment options in Australia are discussed.

Kick detection and well control in a closed wellbore

2011 ◽  
Vol 51 (1) ◽  
pp. 109 ◽  
Author(s):  
Steve Nas
Keyword(s):  
Control Process ◽  
Pressure Control ◽  
Control Device ◽  
Primary Objective ◽  
Pressure Management ◽  
Well Control ◽  
Managed Pressure Drilling ◽  
Drilling Operations ◽  
Control Procedures ◽  
Additional Level

Closing the wellbore at the top with a rotating control device (RCD) for some kinds of managed pressure drilling (MPD) operations raises a number of issues with regards to well control and kick detection. The wellbore is closed and the standard flow check of looking into the well is no longer possible. The use of a RCD provides drillers with an additional level of comfort because it is a pressure management device, but it doesn’t eliminate the need to have well control as a primary objective. In recent MPD operations, it has already been observed that well control procedures are relaxed as a result of managed pressure drilling. Is managed pressure drilling the same as primary well control, and how do we deal with kicks in managed pressure drilling operations? At what point in a well control process do we hand over from MPD to drillers’ well control, and who is responsible? This paper will present some of the issues that need to be considered when planning and conducting MPD operations. Early kick detection and annular pressure control are promoted as an essential part of MPD operations, but there can be confusion as to where the responsibility for well control lies. Does the responsibility remain with the drilling contractor and operator or with the provider of the MPD services. The paper provides some case studies where MPD and well control conflicted, causing a number of issues that in some cases led to the loss of wells.

What Determines Fiscal Deficits in Europe? The Impact and Interaction of EMU Membership, Fiscal Rules, Fiscal Councils and Creative Accounting

2020 ◽  
Vol 71 (1) ◽  
pp. 15-41
Author(s):  
Dominik Maltritz ◽  
Sebastian Wüste
Keyword(s):  
Fiscal Rules ◽  
Special Focus ◽  
Annual Data ◽  
Budget Balance ◽  
Fiscal Deficits ◽  
Eu Countries ◽  
Creative Accounting ◽  
Stock Flow ◽  
The Impact

AbstractWe search for drivers of fiscal deficits in Europe using a data panel containing annual data of 27 EU countries in the years 1991–2012. Our special focus is on the influence of fiscal rules as well as on fiscal councils, i. e. institutions that may help to reduce deficits and enforce fiscal rules by advising governments. We distinguish between internal fiscal rules and external rules that result from EMU membership. In addition, we consider the impact of “creative accounting”, i. e. measures that help to circumvent fiscal rules, which we approximate by so called stock-flow-adjustments. We especially analyze the interactive influence of the mentioned variables on the budget balance.

scholarly journals 26.A. Workshop: Assessing the role of policies and actions to address childhood obesity

2020 ◽  
Vol 30 (Supplement_5) ◽  
Author(s):  
◽  
Keyword(s):  
Public Health ◽  
Childhood Obesity ◽  
Stakeholder Engagement ◽  
Special Focus ◽  
Policy Options ◽  
Sustainable Solutions ◽  
Relevant Evidence ◽  
Multi Stakeholder ◽  
The Impact

Abstract   Childhood obesity has grown to become one of the most dramatic features of the global obesity epidemic, with long-term consequences. The spread of obesity has been fueled by changes in social norms and living environments that have shaped individual behaviours making them conducive to excessive and imbalanced nutrition, sedentary lifestyles, and ultimately obesity and associated diseases. The STOP project will aim to generate scientifically sound, novel and policy-relevant evidence on the factors that have contributed to the spread of childhood obesity in European countries and on the effects of alternative technological and organisational solutions and policy options available to address the problem. STOP will translate the evidence gathered and generated into indicators and measurements, policy briefs and toolkits and multi-stakeholder frameworks. A special focus of STOP is understanding the stakeholders' networks and drivers of stakeholders' action. STOP will establish new ways for policy-relevant evidence to be generated, made available and used in the design and implementation of effective and sustainable solutions for childhood obesity at the EU, national and local levels. Each of the policy work packages will: Produce evidence syntheses and impact simulations for different policy approaches;Assess selected policy approaches and actions in children cohorts and other relevant settings;Devise policy toolkits and policy guidance to support the adoption and implementation of specific actions by relevant actors;Establish a country-based European accountability and monitoring framework in each policy area. The workshop aims to: Showcase the impact of different policy options evaluated throughout the STOP project;Increase participants' understanding and awareness of the opportunities and challenges associated with the implementation of selected policies;Increase awareness of public health professionals of the importance of overcoming siloes in identifying and implementing public health policies;Increase the understanding of multi-stakeholder engagement. The discussion will explore the role of stakeholders across different policy areas. We will explore the different definitions of “stakeholders” and “multi-stakeholders” engagement. This will also be an opportunity to explore some of the benefits, risks and challenges around stakeholder engagement, and explore what are the different types of stakeholders involved in these policies as well as their roles. The workshop will offer an opportunity to: Inform participants about existing physical activity, regulatory and fiscal policies to address childhood obesity;Inform participants about new, innovative EU-level projects that aim to address childhood obesity;Outline preliminary findings of the STOP project with regards to the effectiveness of the evaluated policies;Identify some of the gaps and limitations of existing policies and discuss some of the steps to ensure successful policy implementation. Key messages Present new evidence on what policy approaches work in addressing key determinants of childhood obesity. Showcase findings on the attitudes of different stakeholders towards obesity policies, and debate the benefits, risks and challenges of multi-stakeholder engagement.

scholarly journals The impact of bZIP Atf1ortholog global regulators in fungi

2021 ◽  
Author(s):  
Éva Leiter ◽  
Tamás Emri ◽  
Klaudia Pákozdi ◽  
László Hornok ◽  
István Pócsi
Keyword(s):  
Transcription Factors ◽  
Stress Response ◽  
Secondary Metabolite ◽  
Plant Pathogens ◽  
Leucine Zipper ◽  
Secondary Metabolite Production ◽  
Special Focus ◽  
Human Pathogens ◽  
Metabolite Production ◽  
The Impact

Abstract Regulation of signal transduction pathways is crucial for the maintenance of cellular homeostasis and organismal development in fungi. Transcription factors are key elements of this regulatory network. The basic-region leucine zipper (bZIP) domain of the bZIP-type transcription factors is responsible for DNA binding while their leucine zipper structural motifs are suitable for dimerization with each other facilitiating the formation of homodimeric or heterodimeric bZIP proteins. This review highlights recent knowledge on the function of fungal orthologs of the Schizosaccharomyces pombe Atf1, Aspergillus nidulans AtfA, and Fusarium verticillioides FvAtfA, bZIP-type transcription factors with a special focus on pathogenic species. We demonstrate that fungal Atf1-AtfA-FvAtfA orthologs play an important role in vegetative growth, sexual and asexual development, stress response, secondary metabolite production, and virulence both in human pathogens, including Aspergillus fumigatus, Mucor circinelloides, Penicillium marneffei, and Cryptococcus neoformans and plant pathogens, like Fusarium ssp., Magnaporthe oryzae, Claviceps purpurea, Botrytis cinerea, and Verticillium dahliae. Key points • Atf1 orthologs play crucial role in the growth and development of fungi. • Atf1 orthologs orchestrate environmental stress response of fungi. • Secondary metabolite production and virulence are coordinated by Atf1 orthologs.

scholarly journals Environmental Changes and Cultural Transitions in SW Iberia during the Early-Mid Holocene

2021 ◽  
Vol 11 (8) ◽  
pp. 3580
Author(s):  
Cristina Val-Peón ◽  
Juan I. Santisteban ◽  
José A. López-Sáez ◽  
Gerd-Christian Weniger ◽  
Klaus Reicherter
Keyword(s):  
Dietary Habits ◽  
Environmental Changes ◽  
Source Area ◽  
Direct Access ◽  
Special Focus ◽  
Early Neolithic ◽  
Archaeological Data ◽  
Local Resources ◽  
Climate Events ◽  
The Impact

The SW coast of the Iberian Peninsula experiences a lack of palaeoenvironmental and archaeological data. With the aim to fill this gap, we contribute with a new palynological and geochemical dataset obtained from a sediment core drilled in the continental shelf of the Algarve coast. Archaeological data have been correlated with our multi-proxy dataset to understand how human groups adapted to environmental changes during the Early-Mid Holocene, with special focus on the Mesolithic to Neolithic transition. Vegetation trends indicate warm conditions at the onset of the Holocene followed by increased moisture and forest development ca. 10–7 ka BP, after which woodlands are progressively replaced by heaths. Peaks of aridity were identified at 8.2 and 7. 5 ka BP. Compositional, textural, redox state, and weathering of source area geochemical proxies indicates abrupt palaeoceanographic modifications and gradual terrestrial changes at 8.2 ka BP, while the 7.5 ka BP event mirrors a decrease in land moisture availability. Mesolithic sites are mainly composed of seasonal camps with direct access to the coast for the exploitation of local resources. This pattern extends into the Early Neolithic, when these sites coexist with seasonal and permanent occupations located in inland areas near rivers. Changes in settlement patterns and dietary habits may be influenced by changes in coastal environments caused by the sea-level rise and the impact of the 8.2 and 7.5 ka BP climate events.

scholarly journals Erythrocytes: Central Actors in Multiple Scenes of Atherosclerosis

2021 ◽  
Vol 22 (11) ◽  
pp. 5843
Author(s):  
Chloé Turpin ◽  
Aurélie Catan ◽  
Olivier Meilhac ◽  
Emmanuel Bourdon ◽  
François Canonne-Hergaux ◽  
...  
Keyword(s):  
Iron Homeostasis ◽  
The Body ◽  
Diabetic Patients ◽  
Special Focus ◽  
Plaque Progression ◽  
Cell Dysfunction ◽  
Circulating Cells ◽  
The Impact ◽  
Progression Of Atherosclerosis

The development and progression of atherosclerosis (ATH) involves lipid accumulation, oxidative stress and both vascular and blood cell dysfunction. Erythrocytes, the main circulating cells in the body, exert determinant roles in the gas transport between tissues. Erythrocytes have long been considered as simple bystanders in cardiovascular diseases, including ATH. This review highlights recent knowledge concerning the role of erythrocytes being more than just passive gas carriers, as potent contributors to atherosclerotic plaque progression. Erythrocyte physiology and ATH pathology is first described. Then, a specific chapter delineates the numerous links between erythrocytes and atherogenesis. In particular, we discuss the impact of extravasated erythrocytes in plaque iron homeostasis with potential pathological consequences. Hyperglycaemia is recognised as a significant aggravating contributor to the development of ATH. Then, a special focus is made on glycoxidative modifications of erythrocytes and their role in ATH. This chapter includes recent data proposing glycoxidised erythrocytes as putative contributors to enhanced atherothrombosis in diabetic patients.

Immunoglobulin levels in systemic lupus erythematosus: A narrative review

Lupus ◽  
2021 ◽  
pp. 096120332110047
Author(s):  
Ibrahim Almaghlouth ◽  
Sindhu R Johnson ◽  
Eleanor Pullenayegum ◽  
Dafna Gladman ◽  
Murray Urowitz
Keyword(s):  
Systemic Lupus Erythematosus ◽  
Lupus Erythematosus ◽  
Narrative Review ◽  
Special Focus ◽  
Immunoglobulin Level ◽  
Systemic Lupus ◽  
External Threats ◽  
Self Tolerance ◽  
Low Levels ◽  
The Impact

Immunoglobulins play a fundamental role in the protection of the human body against internal and external threats. They also contribute to the immune system homeostasis and maintenance of self-tolerance. Hypogammaglobulinemia is occasionally encountered in routine clinical practice by rheumatologists. Low levels of immunoglobulins can occur as primary or secondary issues and may predispose patients to various forms of infection. However, the impact of the low immunoglobulin level abnormality varies with the underlying condition. In this narrative review, we shed light on the overall types and functions of immunoglobulins for clinicians. We discuss important principles of immunoglobulin measurements. We then consider the primary and secondary causes of low immunoglobulins with a special focus on hypogammaglobulinemia in patients with systemic lupus erythematosus (SLE).

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