Literatura científica selecionada sobre o tema "Seveso Upper Tier"

Abstract The purpose of this publication is to present the characteristics of upper-tier and lower-tier establishments of a major accident, which operate under the provisions of the Seveso III Directive. The article will also present information about the number of these establishments in the EU and Poland. Analysis of the data on the operation of upper-tier and lower-tier establishments of a major accident comparison with the number of major accidents which took place will allow for assessment of the effects of the implementation of the provisions of the Seveso III Directive by EU countries.

We present a case of a two-year-old boy with hemophilia A and high titer factor inhibitor, who developed forearm compartment syndrome two days after taking blood samples for a regular check-up of serum concentration of Factor VIII. Emergency fasciotomy was performed to prevent Volkmann contracture. The patient needed bypass therapies including recombitant activated factor VII (rFVIIa), activated prothrombin complexes (aPCC), factors VII・X (MC7-10), and transfusions. Eleven days after the surgical intervention, he was discharged without any functional loss in the affected upper extremity. Early surgical intervention prevented compartment syndrome of affected upper extreme.

The work is aimed at determining the age of ice wedges, as well as at characterizing winter temperature fluctuations during the formation of the Yedoma based on the isotopic composition of ice wedges in the unique outcrop of the Batagay mega-slump. The researchers carried out a detailed sampling from the Upper Ice Wedge Complex of the Batagay Yedoma, determined the isotopic composition in three ice wedges at different altitudes. The results of radiocarbon dating of organic matter from ice wedge confirm the time of syngenetic formation of the upper-tier ice wedges in the range from 27.2 to 30.8 thousand cal. years. Ice wedges of the lower tier, according to the results of radiocarbon dating of ice accumulated 44.7—47.9 thousand years ago simultaneously at different levels: 274—268 m and 224—227 respectively. The study of yedoma deposits and ice-wedge ice made it possible to obtain data on climatic fluctuations in a region with the most severe continental climate. Direct radiocarbon dating of syngenetic ice wedges provided dating of ice growth in the Batagay yedoma, data on the content of stable isotopes in the ice demonstrated stable and very harsh conditions of the winter season. The air paleotemperature in Batagay in January 47—42 and 30—25 thousand cal. years ago was consistently low about –51°C.

Heavy monsoon rainfall ravaged a large swath of East Asia in summer 2020. Severe flooding of the Yangtze River displaced millions of residents in the midst of a historic public health crisis. This extreme rainy season was not anticipated from El Niño conditions. Using observations and model experiments, we show that the record strong Indian Ocean Dipole event in 2019 is an important contributor to the extreme Yangtze flooding of 2020. This Indian Ocean mode and a weak El Niño in the Pacific excite downwelling oceanic Rossby waves that propagate slowly westward south of the equator. At a mooring in the Southwest Indian Ocean, the thermocline deepens by a record 70 m in late 2019. The deepened thermocline helps sustain the Indian Ocean warming through the 2020 summer. The Indian Ocean warming forces an anomalous anticyclone in the lower troposphere over the Indo-Northwest Pacific region and intensifies the upper-level westerly jet over East Asia, leading to heavy summer rainfall in the Yangtze Basin. These coupled ocean-atmosphere processes beyond the equatorial Pacific provide predictability. Indeed, dynamic models initialized with observed ocean state predicted the heavy summer rainfall in the Yangtze Basin as early as April 2020.

Abstract. This study was designed to investigate the dynamics of current and future surface water availability for different water users in the upper Pangani River Basin under changing climate. A multi-tier modeling technique was used in the study, by coupling the Soil and Water Assessment Tool (SWAT) and Water Evaluation And Planning (WEAP) models, to simulate streamflows under climate change and assess scenarios of future water availability to different socio-economic activities by year 2060. Six common Global Circulation Models (GCMs) from WCRP-CMIP3 with emissions Scenario A2 were selected. These are HadCM3, HadGEM1, ECHAM5, MIROC3.2MED, GFDLCM2.1 and CSIROMK3. They were downscaled by using LARS-WG to station scale. The SWAT model was calibrated with observed data and utilized the LARS-WG outputs to generate future streamflows before being used as input to WEAP model to assess future water availability to different socio-economic activities. GCMs results show future rainfall increase in upper Pangani River Basin between 16–18 % in 2050s relative to 1980–1999 periods. Temperature is projected to increase by an average of 2 ∘C in 2050s, relative to baseline period. Long-term mean streamflows is expected to increase by approximately 10 %. However, future peak flows are estimated to be lower than the prevailing average peak flows. Nevertheless, the overall annual water demand in Pangani basin will increase from 1879.73 Mm3 at present (2011) to 3249.69 Mm3 in the future (2060s), resulting to unmet demand of 1673.8 Mm3 (51.5 %). The impact of future shortage will be more severe in irrigation where 71.12 % of its future demand will be unmet. Future water demands of Hydropower and Livestock will be unmet by 27.47 and 1.41 % respectively. However, future domestic water use will have no shortage. This calls for planning of current and future surface water use in the upper Pangani River Basin.

Facing more and more severe global warming problems, renewable energy, as an alternative to traditional fossil fuels, is attracting more and more attentions due to its capability of reducing carbon emission. This paper considers two-tier HetNets with orthogonal frequency division multiple access (OFDMA), where the macro base station (MBS) is powered by power grid and small base stations (SBSs) have hybrid energy supplies. Through smart grid, SBSs can share their renewable energy with each other. We consider the problem of cross-layer interference caused by spectrum reuse, the burst of user data, and the randomness of renewable energy arrivals. Through energy cooperation, this paper investigates maximizing the time-average energy efficiency of SBSs. Based on user data queue and SBS energy queue, the optimal problem is decoupled into two subproblems by Lyapunov optimization: resource allocation subproblem and energy scheduling and energy cooperation subproblem. By solving two subproblems, the online solution to the optimization problem is obtained. Through theoretical analysis and simulations, both user data queues and energy queues have an upper bound, the network is stable, and the proposed algorithm performs better than the basic algorithm without energy cooperation.

Abstract. Here we for the first time present a nationwide characterization of flood hazards across China. Our analysis is based on an exceptional dataset of 1120 stream gauging stations with continuous records of annual flood peaks for at least 50 years across the entire country. Our results are organized by centering on various aspects of flood peak distributions, including temporal changes in flood series and their spatial variations, the statistical distribution of extreme values, and the properties of storms that lead to annual flood peaks. These aspects altogether contribute to an improved understanding of flood hydrology under a changing environment over China and promote advances in flood science at the global scale. Historical changes in annual flood peaks demonstrate frequent abrupt changes rather than slowly varying trends. The dominance of decreasing annual flood peak magnitudes indicates a weakening tendency of flood hazards over China in recent decades. We model the upper tails of flood peaks based on the generalized extreme value (GEV) distributions. The GEV shape parameter is weakly dependent on drainage area, but it shows spatial splits tied to rainfall climatology between northern and southern China. Landfalling tropical cyclones play an important role in characterizing the upper-tail properties of flood peak distributions especially in northern China and southeastern coast, while the upper tails of flood peaks are dominated by extreme monsoon rainfall in southern China. Severe flood hazards associated with landfalling tropical cyclones are characterized by complex interactions of storm circulations with synoptic environments (i.e., mid-latitude baroclinic disturbances) and regional topography.

Abstract The sensitivity of tropical cyclone intensity to ventilation of cooler, drier air into the inner core is examined using an axisymmetric tropical cyclone model with parameterized ventilation. Sufficiently strong ventilation induces cooling of the upper-level warm core, a shift in the secondary circulation radially outward, and a decrease in the simulated intensity. Increasing the strength of the ventilation and placing the ventilation at middle to lower levels results in a greater decrease in the quasi-steady intensity, whereas upper-level ventilation has little effect on the intensity. For strong ventilation, an oscillatory intensity regime materializes and is tied to transient convective bursts and strong downdrafts into the boundary layer. The sensitivity of tropical cyclone intensity to ventilation can be viewed in the context of the mechanical efficiency of the inner core or a modified thermal wind relation. In the former, ventilation decreases the mechanical efficiency, as the generation of available potential energy is wasted by entropy mixing above the boundary layer. In the latter, ventilation weakens the eyewall entropy front, resulting in a decrease in the intensity by thermal wind arguments. The experiments also support the existence of a threshold ventilation beyond which a tropical cyclone cannot be maintained. Downdrafts overwhelm surface fluxes, leading to a precipitous drop in intensity and a severe degradation of structure in such a scenario. For a given amount of ventilation below the threshold, there exists a minimum initial intensity necessary for intensification to the quasi-steady intensity.

Intensive groundwater abstraction has augmented socio-economic development worldwide but threatens the sustainability of groundwater resources. Spatiotemporal analysis of groundwater storage changes is a prerequisite to sustainable water resource management over river basins. To estimate the groundwater storage changes/anomalies (GWCs) in the Indus River Basin (IRB), where observation wells are sparse, Gravity Recovery and Climate Experiment, the Global Land Data Assimilation System, and the WaterGAP Hydrological Model data were employed. The groundwater storage changes and controlling factors were investigated at three tier levels (TTLs), i.e., the basin, river reach, and region, to explore their implications on regional water resource management and provide management options at each level. Overall, the IRB groundwater declined from January 2003 to December 2016, with a relatively higher rate during 2003–2009 than during 2010–2016. Spatially, according to a reach-specific analysis, 24%, 14%, and 2% of the upper, middle, and lower reaches of the IRB, respectively, were indicated by a ‘severe groundwater decline’ over the entire period (i.e., 2003–2016). The GRACE-based GWCs were validated with in situ data of two heterogeneous regions, i.e., Kabul River Basin (KRB) and Lower Bari Doab Canal (LBDC). The analysis showed a correlation (R2) of 0.77 for LBDC and 0.29 for KRB. This study’s results reveal that climatic variations (increase in evapotranspiration); anthropogenic activities, i.e., pumping for irrigation; and water allocations in these regions mainly drive the groundwater storage changes across the Indus Basin.

Background Expression of angiotensin-converting enzyme (ACE)-2 and co-factors like furin, play key-roles in entry of SARS-CoV-2 into host cells. Furin is also involved in oral carcinogenesis. We investigated their expression in oral pre-malignant/malignant epithelial pathologies to evaluate whether ACE2 and furin expression might increase susceptibility of patients with these lesions for SARS-CoV-2 infection. Methods Study included normal oral mucosa (N = 14), epithelial hyperplasia-mild dysplasia (N = 27), moderate-to-severe dysplasia (N = 24), squamous cell carcinoma (SCC, N = 34) and oral lichen planus (N = 51). Evaluation of ACE2/furin membranous/membranous-cytoplasmic immunohistochemical expression was divided by epithelial thirds (basal/middle/upper), on a 5-tier scale (0, 1—weak, 1.5 –weak-to-moderate, 2—moderate, 3—strong). Total score per case was the sum of all epithelial thirds, and the mean staining score per group was calculated. Real time-polymerase chain reaction was performed for ACE2-RNA. Statistical differences were analyzed by One-way ANOVA, significance at p<0.05. Results All oral mucosa samples were negative for ACE2 immuno-expression and its transcripts. Overall, furin expression was weakly present with total mean expression being higher in moderate-to-severe dysplasia and hyperplasia-mild dysplasia than in normal epithelium (p = 0.01, each) and SCC (p = 0.008, p = 0.009, respectively). Conclusions Oral mucosa, normal or with epithelial pathologies lacked ACE2 expression. Furin was weak and mainly expressed in dysplastic lesions. Thus, patients with epithelial pathologies do not seem to be at higher risk for SARS-CoV-2 infection. Overall, results show that oral mucosae do not seem to be a major site of SARS-CoV-2 entry and these were discussed vis-à-vis a comprehensive analysis of the literature.

Les sites industriels à haut risque (ex. Seveso Seuil Haut (SH) ou installations classées à risques majeurs (MHF)) sont classées par des législations et des réglementations comme les sites les plus dangereux. En d’autres termes, en cas d’accident majeur, les dommages peuvent être importants même si c’est rare d’avoir un tel accident. Les politiques de prévention des risques et de gestion de crise sont un moyen de les prévenir tout en maintenant la vitalité économique du secteur industriel. Ces compromis constituent un défi majeur pour les gouvernements et les différents acteurs publics, qui ont pour rôle principal de protéger leurs citoyens et d’améliorer leur bien-être social en prenant des décisions politiques et en développant des politiques “effective” de prévention des risques de gestion de crise. Mais comment peut-on évaluer cette “effectivité” et que signifie-t-elle ? Certes, en fin de compte, une politique de prévention des risques doit réduire les risques et prévenir les accidents (ex., efficacité), mais quels sont les aspects qui conditionnent cette performativité ? Certaines réponses à ces questions pluridisciplinaires peuvent être trouvées dans les différents axes de recherche de l’administration publique, des sciences de la décision, du risque, de la sécurité et de la recherche réglementaire. En ce qui concerne les politiques publiques, les études soulignent les lacunes liées (i) au rôle d’une gouvernance effective des risques et (ii) au rôle crucial lié à la performativité de l’inspection, de la supervision ou du suivi, qui est souvent négligé en dépit de son importance. L’objectif de cette thèse est donc de répondre, par une approche ascendante, à la question de recherche suivante : Comment le “système de politique de prévention des risques” autour des sites industriels à haut risque peut-il être évalué pour un processus de décision effective en prenant en considération les niveaux territoriaux tels que le niveau Régional pour la France et le niveau de l’État pour l’Australie ?Basée sur des approches qualitatives, cette thèse vise à proposer un cadre d’évaluation multicritère servant à la réflexion conceptuelle et au cadrage des problèmes pour l’évaluation de la politique des risques. Elle suggère d’adopté la complexité d’un système de politique publique de prévention et de gestion des risques qui combine (i) un système organisationnel et de gouvernance ; et (ii) un système réglementaire ou normatif ; et (iii) un système d’outils/instruments pratiques. Le cadre d’évaluation est ensuite testé et enrichi à travers deux études de cas qualitatives dans la Région de Normandie (France) et dans l’État de Victoria (Australie), deux divisions administratives où il existe un nombre important de sites à haut risque. Les principales contributions comprennent (i) un cadre d’évaluation de plus de dix critères associés à des questions pratiques adaptées aux contextes des sites industriels à haut risque. Ils incluent des conditions de légitimité et de validité telles que l’efficacité, la transparence, etc. ; et (ii) deux évaluations descriptives approfondies des systèmes Normand et Victorien permettant de déduire certaines des principales variabilités dans l’effectivité de leurs deux systèmes. Certaines limites concernent la généralisation, le champ d’application et la représentativité sont discutés. Les travaux futurs pousseront à tester et enrichir ce cadre sur d’autres cas, à explorer les sites qui se trouvent aux frontières législatives et réglementaires, à examiner les interrelations et les dépendances entre les critères et à explorer les méthodes d’agrégation qui servirait à la formalisation de ce cadre
High-risk industrial sites (e.g., Seveso Upper Tier (UT) and Major Hazard Facilities (MHF)) are classified by legislation and regulations as the most dangerous sites. In other words, in case of a major accident, damage can be significant even if it is supposed to occur rarely. Risk prevention and crisis management policies are one way to prevent that while sustaining the economic vitality of the industrial sector. These trade-offs constitute a major challenge for governments and public actors, who have a primary role in protecting their citizens and improving their social well-being by taking political decisions and developing “effective” risk prevention and crisis management policies.How can we assess such policy “effectiveness” and what does it mean? Ultimately, a risk policy must reduce risks and prevent major accidents (e.g., efficacy), but what other aspects condition such performativity? Some answers to these multidisciplinary questions can be found in public administration, management and decision sciences, risk, safety, and regulatory research areas. Under the public policy dimension, studies emphasize gaps related to (i) the role of effective risk governance and (ii) the central role of inspection, oversight, or monitoring performance, which is often overlooked despite its importance. The objective of this thesis is, therefore, to answer with a bottom-up approach the following research question: How can the “risk policy system” around high-risk sites be assessed for an effective decision process taking into consideration the territorial levels such as the Regional level for France and the State level for Australia?Based on qualitative approaches, this thesis aims to propose a multicriteria assessment framework serving conceptual thinking and problem framing for risk policy assessment. It suggests embracing the complexity of a system that combines (i) an organizational and governance system, (ii) a regulatory or normative system, and (iii) a system of practical tools/instruments. The assessment framework is also tested through two qualitative case studies in the Normandy Region (France) and the State of Victoria (Australia), which are both areas where a significant number of high-risk facilities exist.Main contributions include (i) an assessment framework of more than ten criteria coupled with practical questions adapted to the contexts of high-risk industrial sites. They include conditions for legitimacy and validity such as efficacy, transparency, adequacy, and so on; and (ii) two in-depth descriptive assessments of the Normand and Victorian risk policy systems allow us to deduce some main variabilities in their system’s effectiveness. Some limitations appear to concern generalization, scoping, and representativity aspects. Future work encourages testing this framework on other cases, exploring the groups of facilities at the legislative and regulatory boundaries, examining the inter-relationships and dependencies between criteria, and exploring the aggregation methods that can serve the formalization of this framework

Abstract THERE HAS BEEN A LOT OF TALK around universities lately about core curricula, the canon, the culturally excluded, and a variety of related topics. I both welcome and sometimes tire of these discussions because real engagement doesn’t quite seem to take place. In an effort to see the world from a different perspective, let’s try to think about the evolution of universities and seek some insights from the past. In the Middle Ages, curriculum at all levels was determined in large part by the range of intellectual interest and the dominance of the Church in European education. As the universities emerged, a system of instruction was developed along the following lines: 1. Propaedeutics-Latin and Holy Writ. This was canon in the strictest sense, establishing the ecclesiastical foundations of education. 2. The trivium the lower level of the seven liberal arts, consisting of grammar, rhetoric, and logic. These were, and are, tools of thought to proceed to the next level. 3. The quadrivium the upper-level liberal arts, consisting of geometry, arithmetic, music, and astronomy. 4. Philosophy the highest level of education, which was much less narrowly spelled out than the other levels.

This paper employs the finite element (FE) modeling method to investigate the contributing factors to the “horizontal” splitting cracks observed in the upper strand plane in some concrete crossties made with seven-wire strands. The concrete tie is modeled as a concrete matrix embedded with prestressing steel strands. A damaged plasticity model that can predict the onset and propagation of tensile degradation is applied to the concrete material. An elasto-plastic bond model developed in-house is applied to the steel-concrete interface to account for the interface bond-slip mechanisms and particularly the dilatational effects that can produce the splitting forces. The pretension release process is simulated statically, followed by the dynamic simulations of cyclic rail seat loading. The concrete compressive strength at which the pretension in the strands is released, or release strength, affects both the concrete behavior and the bond characteristics. Three concrete release strengths, 3500, 4500 and 6000 psi, are considered in the simulations. Concrete tie models without and with a fastening system are developed and simulated to examine the effect of embedded fastener shoulders and fastener installation. The fastener shoulders are seated relatively deeply reaching between the two rows of strands. There is instant concrete material degradation adjacent to the strand interfaces near the tie ends upon pretension release. Without the fastening system in the model, the 3500 psi release strength leads to a high degree of degradation that is coalesced and continuous in the upper and lower strand planes, respectively. The damage profiles with the higher release strengths are more discrete and disconnected. Dynamic loading appears to increase the degree of degradation over time. In all cases, the upper strand plane is not dominant in the degree or the extent of material degradation, in contrast to the field observations that the horizontal splitting occurred in the upper strand plane only. Further simulations with the fastener model at 3500 psi concrete release strength indicate that the fastener installation process does not worsen the damage profile. However, the presence of fastener shoulders in the concrete matrix changes the stress distribution and redirects more concrete damages to the upper strand plane, while leaving disconnected damages in the lower strand plane. Under repeated dynamic rail loading, this potentially reproduces the exact upper strand plane, horizontal cracking pattern observed in the field. Subjected to further experimental verification, the FE analyses identify three contributing factors to the horizontal macro-cracks occurring at the specific upper strand level: (1) relatively low concrete release strength during production, (2) embedded fastener shoulders that redistribute concrete damages to the upper strand plane, and (3) a sufficiently large number of dynamic rail loading cycles for the microscopic damages to develop into macro-cracks. The number of dynamic loading cycles needed to produce macro-cracks should increase with the increased concrete release strength.

IRSN uses a two-tier approach for development of codes analysing the course of a hypothetical severe accident (SA) in a Pressurized Water Reactor (PWR): on one hand, the integral code ASTEC, jointly developed by IRSN and GRS, for fast-running and complete analysis of a sequence; on the other hand, detailed codes for best-estimate analysis of some phenomena such as ICARE/CATHARE, MC3D (for steam explosion), CROCO and TONUS. They have been extensively used to support the level 2 Probabilistic Safety Assessment of the 900 MWe PWR and, in general, for the safety analysis of the French PWR. In particular the codes ICARE/CATHARE, CROCO, MEDICIS (module of ASTEC) and TONUS are used to support the safety assessment of the European Pressurized Reactor (EPR). The ICARE/CATHARE code system has been developed for the detailed evaluation of SA consequences in a PWR primary system. It is composed of the coupling of the core degradation IRSN code ICARE2 and of the thermalhydraulics French code CATHARE2. The CFD code CROCO describes the corium flow in the spreading compartment. Heat transfer to the surrounding atmosphere and to the basemat, leading to the possible formation of an upper and lower crust, basemat ablation and gas sparging through the flow are modelled. CROCO has been validated against a wide experimental basis, including the CORINE, KATS and VULCANO programs. MEDICIS simulates MCCI (Molten-Corium-Concrete-Interaction) using a lumped-parameter approach. Its models are being continuously improved through the interpretation of most MCCI experiments (OECD-CCI, ACE…). The TONUS code has been developed by IRSN in collaboration with CEA for the analysis of the hydrogen risk (both distribution and combustion) in the reactor containment. The analyses carried out to support the EPR safety assessment are based on a CFD formulation. At this purpose a low-Mach number multi-component Navier-Stokes solver is used to analyse the hydrogen distribution. Presence of air, steam and hydrogen is considered as well as turbulence, condensation and heat transfer in the containment walls. Passive autocatalytic recombiners are also modelled. Hydrogen combustion is afterwards analysed solving the compressible Euler equations coupled with combustion models. Examples of on-going applications of these codes to the EPR safety analysis are presented to illustrate their potentialities.

The Baong Formation is one of the formations that have hydrocarbon potential in the Aru Sub Basin, North Sumatra Basin. However, there is still limited geological information in the area including the Analysis of Sequence Stratigraphy. The geological information is also needed to easier find out the distribution of potential layers of oil and gas in order to maximize exploration results. The method used in this research was Electrofacies Analysis to show the appearance of rock grain size and geological processes that affect formation. Well--Seismic Tie and interpretation of the horizon along with structures was conducted to produce a Time Structure Map and correlate the sequences in well logs and 2D seismic cross-section to define the lateral distribution of each sequence. Based on the third-order sequence, the Baong Formation was divided into two system tract types: Lowstand System Tract (LST) and Transgressive System Tract (TST). Maximum Flooding Surface (MFS) is the lower boundary of LST, Transgressive Surface (TS) is the boundary between LST and TST, and Maximum Flooding Surface is the upper boundary of TST. Based on fourth-order sequence, each system tracts was divided into seven parasequences with Flooding Surface as the boundary. The research area can also be interpreted into a conceptual model of the hydrocarbon system.

The Baong Formation is one of the formations that has hydrocarbon potential in the Aru Sub Basin, North Sumatra Basin (Figure 1). However, geological information in that area is still far less than is available in others. Analysis of sequence stratigraphy needs to be done to enrich geological information of the study area, maximize the results of exploration before exploitation, and make it easier to find the distribution of potential layers of oil and gas. Methods that are used in this research are electrofacies analysis to show the appearance of rock grain size and geological processes that affect its formation, Well Seismic Tie and interpretation of the horizon along with structures to produce a Time Structure Map, and correlate the sequences in log wells and 2D seismic cross section to know the same area of each sequence. Based on third-order sequence, the Baong Formation was divided into two types of system tract, such as Lowstand System Tract (LST) and Transgressive System Tract (TST). Maximum Flooding Surface (MFS) as the lower boundary of LST, Transgressive Surface (TS) as the boundary between LST and TST, and Maximum Flooding Surface as the upper boundary of TST. Based on fourth-order sequence, each of the system tracts was divided into seven parasequences with Flooding Surface as the boundary. The research area can also be interpreted into a conceptual model of a hydrocarbon system.

Abstract Self-shielded flux-cored arc welding (FCAW-S) has been widely used in some parts of the world for mainline and tie-in welding of large diameter pipelines for many years. FCAW-S offers high deposition rates and requires less equipment than gas-shielded wire processes. Consequently, FCAW-S is an attractive option for girth welding under difficult field conditions (e.g., windy, remote and/or challenging terrain) and is under consideration as an alternative to shielded metal arc welding (SMAW) with cellulosic electrodes due to several well-documented girth weld failures of predominantly newly constructed X70 pipelines in North America. While FCAW-S is not likely to produce weld properties as robust as is possible with mechanized gas metal arc welding (GMAW, GMAW-P) or gas-shielded flux-cored arc welding (FCAW-G), it is evident that FCAW-S offers higher performance and productivity than SMAW with cellulosic electrodes. This paper provides a comprehensive update of key considerations and drivers that influence FCAW-S weld toughness, specifically the causes of seemingly large variation in CVN energy through the transition region. CVN transition curves were developed for seven E81T8 FCAW-S welds fabricated under a range of welding conditions represented by heat inputs ranging from 0.6 to 1.7 kJ/mm. Toughness performance, measured as mid-transition temperature was considered in the context of fracture morphology below the CVN notches and metallographic examination of notch locations in transverse and longitudinal weld sections. Analysis indicates that toughness improves when welding practices are employed that maximize the amount of reheated weld metal at the Charpy notch location. Comparison of CVN performance with E8010 cellulosic SMAW under welding conditions typical for pipeline girth welds, the FCAW-S exhibits higher upper shelf energies and lower mid-transition temperatures. The FCAW-S and cellulosic SMAW were also compared relative to HAZ softening and weld strength overmatching using the data from microhardness maps. HAZ results indicate the FCAW-S will produce a narrower softened zone than the SMAW for a given steel at a comparable heat input. Weld metal results indicate greater potential for overmatching an X70 specified strength range with FCAW-S. The outcome indicates that FCAW-S can be a viable option for girth welding of high strength pipelines provided certain process controls and welding practices are implemented. Recommendations for improving performance are provided for consideration.

Abstract Based on the production data from first development campaign in 2017, contamination reading of CO2 and H2S from gas production wells were observed increasing from 3% to 10% and from 3ppm to 16ppm respectively within one year production. These findings have triggered the revisit in 2019 development campaign optimization strategy in terms of material selection, number of wells, reservoir targets, and completion design. Thus, tubing material was upgraded to HP1-13CR for the upper part of tubing up to 10,000 ft-MDDF (feet measure depth drilling rig floor) to avoid SSC risk due to the geostatic undisturbed temperature is less than 80 deg C, however the material of deeper tubing remains as 13CR-L80 as per 2017 campaign. Moreover, the mercury content from first campaign was observed to be above threshold limit from intermediate reservoir based on mercury mapping exercise done in August 2018.As the mercury removal system is not incorporated in the surface facilities, the mercury reading from the well in the 2019 campaign need a close monitoring during well testing so that appropriate action can be taken in case the recorded contaminant reading is high. Dedicated zonal sampling plan to be performed if the commingle zone (total) mercury reading was recorded to be above the threshold limit, and that zones will be shut off to preserve the surface facilities. Opportunity was grabbed to optimize number of wells by completing both shallow and intermediate sections in a single selective completion to maximize the project value. However, this combination will lead to major challenges during operation due to the huge difference in reservoir pressure and permeability contrast in each perforated reservoir as the required overbalanced pressure of completion brine for shallow reservoir is much lesser than the requirement for the mildly overpressure intermediate reservoir. Thus, a potential risk of severe losses and well control is present at shallow reservoir. To mitigate this risk, loss circulation material was pre-spotted in the TCP (Tubing conveyed perforation) BHA prior to fire the gun to allow for self-curing process should losses take place. During the first development campaign, the completion tubing was running in hole in two stages. The lower completion was deployed via drill pipe and the perforated zones was secured with fluid loss device located between lower completion tubing and gravel pack packer. The upper completion tubing was then deployed and tied back to the lower completion packer. This approach was applied as mitigation to prevent fluid losses and to ensure the tubing can be safely deployed to the intended final depth. However, based on the actual performance and losses rate data during the first campaign, the completion design in second campaign was optimized and deployed in single stage. Since shallow and intermediate reservoir were combined in multiple production zones where five SSD (Sliding Side Door) were installed, the slickline option to set packer was waived due to the risk of setting tubing plug in deep wells. Pump out plug was considered as an option but then dropped due to high hydrostatic pressure. The packer setting pressure was too close to plug shear pressure. Therefore, a self-disappearing plug was utilized as it did not require any slickline intervention and can be ruptured by pressure cycle. With this option, risk of pre-mature rupture of plug was eliminated. The paper will discuss in detail each challenge mentioned above together with details calculation that was performed throughout evaluation and selection processes prior best solution being selected as these optimizations resulted in nearly three days saving of rig time, contributing to 2.6% of well cost reduction and the required number of wells were optimized to be three instead of four wells. Moreover, a safer production life of wells by selecting a suitable tubing material and eliminating the risk of mercury production above the above threshold limit.

This research is aimed at finding a new type of notch that would produce propagation data similar to that produced by the PC DWTT. High-toughness materials and materials that had previously been studied were used assuming that if the new notch worked on these materials it would be satisfactory for lower toughness materials. Several notch modifications were tried and most were no better than the standard pressed notch used in the API specimen. A search for a new type of notch for the standard drop-weight-tear-test (DWTT) specimen has been completed. This new notch specimen is to replace the precracked DWTT specimen which has been shown to predict full-scale behavior but has received-little support from pipe manufacturers. The new notch is a chevron notch causing fracture initiation to occur at a machined point located at mid-wall thicknessand about 0.2 inch below the specimen edge (i.e., at the same depth as the pressed-in notch of the standard DWTT). No precracking or other severe prestraining, which may create strain aging problems, is required to produce the specimen. A good correlation was obtained between the chevron-notched DWTT and the Charpy V-notch specimens for conventionally rolled steels; this correlation effectively ties the chevron notched data to past fracture research data and to published correlations thatdescribe fracture in terms of Charpy upper-shelf energy. A procedure is included for preparing and conducting the Chevron notched DWTT.

The British Standards Institute document PD6493:1980 uses the crack tip opening displacement (CTOD) design curve as a method for determining defect acceptance levels in welded joints. The document is under revision and current proposals for the fracture section of the revised document employ three levels of assessment procedures, arranged as a progression from simple stress treatments producing conservative results, to critical analyses which incorporate more rigorous stress analyses and contain no inherent factors of safety. The proposed Level 1 assessment procedure is generally consistent with the CTOD design curve methodology of the current document. Changes include a more simplified treatment of stresses and a plastic collapse analysis. Level 1 is intended as a preliminary screening method before moving to the higher-level procedures as appropriate. Level 2 is seen as the most appropriate assessment level for the majority of industrial applications. It employs a collapse modified strip yield model, and allows for more complex stress analysis treatments than Level 1. These treatments take account of the plasticity interaction between primary and secondary stresses. Level 3 provides the most advanced assessment route. It is based on a reference stress approach and in general requires development of accurate stress-strain data for a particular material. Its main areas of application are for materials exhibiting a high work hardening characteristic or for tearing instability analyses.Result: Experimental work was carried out to generate data against which to validate the numerical models used in the subsequent theoretical investigation of safety factors inherent in defect assessment procedures. It is considered appropriate to examine the proposed Levels 1, 2 and 3 assessment procedures in preference to the CTOD design curve of the current document since this three-tier structure will soon supercede the PD6493:1980 approach. The similarities between the Level 1 methodology and the design curve, and also between the Level 2 approach and the previously investigated collapse modified strip yield formulations allow a systematic investigation of any relative change in safety factors between the old and the new methods.Benefit: The validation studies demonstrated that numerical models using true stress-logarithmic strain data gave reasonable predictions of the experimental global displacement and local crack tip response. Plane stress and plane strain succeeded in providing lower and upper bounds respectively to the experimental load-displacement behavior for plain and welded configurations. Plane stress conditions were considered the most suitable for the theoretical safety factor investigation. Level 1 assessment was found to be generally conservative but safety factors less than unity could occur for defects located in severe residual stress fields under high levels of load. Level 2 and Level 3 assessments produced consistent levels of safety when realistic defects at welds were considered which included over-matching weld metal and weld cap reinforcement.