Borehole cement sheath integrity - numerical simulation under reservoir conditions

The most important function of the cement sheath is to provide zonal isolation in a production well. To achieve this objective, a hydraulic seal must be obtained between the casing and the cement, and between the cement and the formation. Throughout the life of a production well the cement sheath is subject to different reservoir conditions. Drilling, changes in pressure and temperature due to production, stimulation, and natural tectonic activity can lead to cement damage. Smaller chronic leakages due to defective well tubulars or damaged cement sheaths in the well cause a loss in the sustained casing pressure (SCP). Ensuring well integrity means to protect the environment against leakage along the well and to guarantee its producing potential. The tool presented in the current paper allows the cement engineer to simulate underground well conditions. After simulating the chosen scenario, various outputs can be combined in the overall analysis, including compression, traction, thermo-elasticity, and microannulus to help the cement engineer to analyze and design the proper cement to be used during the completion process.Publicado en: Mecánica Computacional vol. XXXV, no. 5Facultad de Ingenierí

Borehole cement sheath integrity - numerical simulation under reservoir conditions

The most important function of the cement sheath is to provide zonal isolation in a production well. To achieve this objective, a hydraulic seal must be obtained between the casing and the cement, and between the cement and the formation. Throughout the life of a production well the cement sheath is subject to different reservoir conditions. Drilling, changes in pressure and temperature due to production, stimulation, and natural tectonic activity can lead to cement damage. Smaller chronic leakages due to defective well tubulars or damaged cement sheaths in the well cause a loss in the sustained casing pressure (SCP). Ensuring well integrity means to protect the environment against leakage along the well and to guarantee its producing potential. The tool presented in the current paper allows the cement engineer to simulate underground well conditions. After simulating the chosen scenario, various outputs can be combined in the overall analysis, including compression, traction, thermo-elasticity, and microannulus to help the cement engineer to analyze and design the proper cement to be used during the completion process.Publicado en: Mecánica Computacional vol. XXXV, no. 5Facultad de Ingenierí

Borehole cement sheath integrity - numerical simulation under reservoir conditions

The most important function of the cement sheath is to provide zonal isolation in a production well. To achieve this objective, a hydraulic seal must be obtained between the casing and the cement, and between the cement and the formation. Throughout the life of a production well the cement sheath is subject to different reservoir conditions. Drilling, changes in pressure and temperature due to production, stimulation, and natural tectonic activity can lead to cement damage. Smaller chronic leakages due to defective well tubulars or damaged cement sheaths in the well cause a loss in the sustained casing pressure (SCP). Ensuring well integrity means to protect the environment against leakage along the well and to guarantee its producing potential. The tool presented in the current paper allows the cement engineer to simulate underground well conditions. After simulating the chosen scenario, various outputs can be combined in the overall analysis, including compression, traction, thermo-elasticity, and microannulus to help the cement engineer to analyze and design the proper cement to be used during the completion process.Publicado en: Mecánica Computacional vol. XXXV, no. 5Facultad de Ingenierí

The effect of incorporating high reflectance pigments in thermal enhanced exterior finishing systems

In the recent years, the concerns on building thermal performance tend to follow the challenges imposed by more demanding building design. The increase of new building materials and technologies with improved thermal characteristics, such as ETICS, thermal mortars and high reflectance coatings, contribute to meet the thermal requirements, by lowering the façade U-value and/or the surface temperature variation. This paper has the objective of evaluating the effect of incorporating high reflectance pigments in organic coatings applied in thermal systems, such as ETICS and thermal rendering. The effect on the thermal behaviour is also discussed by comparing them with a non-insulated system. The solar absorptance and the surface temperature of different façade systems with distinct coatings were measured "in situ". The solar absorptance was measured with a pyranometer with an adapted methodology based on the ASTM E1918 standard. The surface temperature of the specimens was continuously monitored for an extended period enabling a comparison under different climatic conditions. The results showed that the incorporation of high reflectance pigments allowed a significant decrease of the solar absorptance even in darker colours and that the absence of thermal insulation proved to have a significant effect on the surface temperature

Specification of requirements models

The main aim of this chapter is to present and discuss a set of modeling and specification techniques, in what concerns their ontology and support in the requirements representation of computer-based systems. A systematic classification of meta-models, also called models of computation, is presented. This topic is highly relevant since it supports the definition of sound specification methodologies in relation to the semantic definition of the modeling views to adopt for a given system. The usage and applicability of Unified Modeling Language (UML) diagrams is also related to their corresponding meta-models. A set of desirable characteristics for the specification methodologies is presented and justified to allow system designers and requirements engineers to more consciously define or choose a particular specification methodology. A heuristic-based approach to support the transformation of user into system requirements is suggested, with some graphical examples in UML notation.(undefined

A centennial catalogue of hydro-geomorphological compound events and corresponding atmospheric forcing

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Catálogo de eventos hidro-geomorfológicos em Portugal Continental (1865-2015)

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The hydro-geomorphologic event of february 1979: weather conditions and impacts

The large amount of floods and landslides that occurred on 5-16 February 1979 in Portugal corresponds to a major hydro-geomorphologic event according to the comprehensive DISASTER database. This event is driven by atmospheric forcing at different time scales that have not been, as yet, studied in detail. Here we show that the precipitation period of February 1979 has produced several multiday accumulated precipitation events, over the Portuguese continental territory, ranking amongst the top 10 events observed between 1950 and 2008. Additionally, most of the precipitation on this event occurs in days with atmospheric circulation dominated by “wet” circulation weather types (CWTs), i.e. cyclonic (C), west (W) or southwest (SW) types.info:eu-repo/semantics/publishedVersio

Saharan air intrusions as a relevant mechanism for Iberian heatwaves: the record breaking events of August 2018 and June 2019

The summers of 2018 and 2019 were characterized by unusually warm conditions over Europe. Here, we describe the intense heatwaves striking the Iberian Peninsula in early August 2018 and late June 2019. The 2018 episode was relatively short-lived but outstanding in amplitude, particularly in western Iberia. Similar to previous mega-heatwaves, the 2019 event was long-lasting and affected large areas of western and central Europe, including eastern Iberia. During these events, many absolute temperature records were broken in western and eastern Iberia, respectively (some of them standing since 2003). In both cases, a cyclonic circulation off the coast in the northeastern Atlantic and a strong subtropical ridge pattern over the affected area promoted the advection of an anomalously warm air mass. This paper highlights the role of these very warm, stable and dry air intrusions of Saharan origin in the western and eastern Iberia heatwave events. Using a thermodynamical classification based on the geopotential height thickness and potential temperature, we show how the magnitude and poleward extension of these Saharan intrusions were unprecedented in the period since 1948. The relationship between Iberian heatwaves and Saharan warm air intrusions is discussed in the long-term context, showing a closer link in southern sectors of the Peninsula. However, a consistent poleward trend in the latitudinal extension of these subtropical intrusions reveals their increasing relevance for heatwaves in northern sectors of Iberia and western Europe. This overall trend is accompanied by an apparent “see-saw” in the occurrence of subtropical intrusions between eastern and western Iberia on multi-decadal scales