Introduktion: Enhanced Recovery After Surgery (ERAS) är ett evidensbaserat vårdprogram inom elektiv kirurgi. Studier har visat att följsamhet över 75% till ERAS-programmet har ett förbättrat utfall efter kirurgi i form av mindre komplikationer, kortare length of stay (LOS) och förbättrad återhämtning. Patientens postoperativa återhämtning efter elektiv ändtarmskirurgi med ERAS-programmet kan vara utmanande på grund av illamående, smärta, intravenösa vätskor, mobilisering och typ av kirurgisk metod, vilket kan leda till att patienten drabbas av komplikationer som förlänger LOS. Intensivvårdssjuksköterskor har en viktig roll i den postoperativa fasen för patienter som vårdas enligt ERAS-programmet relaterat till dennes arbetsområden.Syfte: Att studera följsamheten, kortsiktigt resultat och den postoperativa återhämtningen för patienterna som genomgått elektiv ändtarmskirurgi enligt ett ERAS-program relaterat till intensivvårdssjuksköterskans arbetsområden.Metod: Denna studie är en kvantitativ kohortstudie med retrospektiv ansats. Datainsamling genomfördes med hjälp av ERAS Interactive Audit System databas (EIAS), där 393 patienter mötte inklusion- och exklusionskriterierna. Av dom var 231 patienter opererade med öppen kirurgi och 162 patienter med robotkirurgi. Resultat: I den postoperativa fasen var följsamheten till ERAS-programmet 43.5% för öppen kirurgi och 57.7% för robotkirurgi. Det kortsiktiga resultatet, antalet LOS och komplikationer, visade signifikant skillnad mellan de kirurgiska metoderna. Antalet LOS och komplikationer var högre för öppen kirurgi jämfört med robotkirurgi. I den postoperativa återhämtningen för patienterna kunde det observeras flera signifikanta skillnader i utfallet mellan de kirurgiska metoderna. Patienter som opererats med robotkirurgi hade i flertalet områden bättre utfall jämfört med de som opererats med öppen kirurgi.Slutsats: Resultatet i denna studie visade att den totala följsamheten (pre-, intra- och postoperativ följsamhet) för patienter som följer ett ERAS-programmet efter ändtarmskirurgi inte kom upp i den rekommenderade nivån >75% följsamhet. Trots att patienter följde ett standardiserat vårdprogram som ERAS visade det att uppnå en hög följsamhet har sina utmaningar i form av postoperativ återhämtning. Intensivvårdssjuksköterskan har arbetsområden som kan förbättras för att hjälpa patienterna uppnå målen med ERASprogrammet och därmed säkerställa evidensen för ett bättre utfall i form av snabbare återhämtning, minskade komplikationer och kortare LOS.

Made available in DSpace on 2014-12-17T15:01:36Z (GMT). No. of bitstreams: 1 LuisaCP.pdf: 1955160 bytes, checksum: 7051a33823820be485db53c8225425a3 (MD5) Previous issue date: 2007-02-09 / Petroleum exists in the nature in certain underground formations where it is adsorbed into the rocks pores. For the conventional recovery methods usually only 30% of the oil is extracted and this can be credited, basically, to three aspects: high viscosity of the oil, geology of the formation and high interfacial tensions between the reservoir s fluids. The enhanced recovery methods use the injection of a fluid or fluids mixture in a reservoir to act in points where the conventional process didn't reach the recovery rates. Microemulsion flooding, considered an enhanced method, has the purpose to desorb the oil from the rock formation and to attain an efficient displacement of the oil emulsion. With this in mind, this work was accomplished with two main objectives: the study of the parameters effect that influence a microemulsified system (surfactant and cosurfactant types, C/S rate and salinity) and the evaluation of displacement efficiency with the microemulsions that showed stability in the rich aqueous area. For the analyzed parameters it was chose the microemulsions composition used in the recovery stage: 25% water, 5% kerosene, 46.7% of butanol as cosurfactant and 23.3% of BC or SCO cosurfactant. The core plugs of Assu and Botucatu sandstones were appraised in porosity and permeability tests and then submitted to the steps of saturation with seawater and oil, conventional recovery with water and enhanced recovery with the selected microemulsions. The Botucatu sandstone presented better recovery parameters, and the microemulsion composed with BS surfactant had larger recovery efficiency (26.88%) / O petr?leo ocorre na natureza em determinadas forma??es subterr?neas onde ? adsorvido nos poros destas rochas. Pelos m?todos convencionais de recupera??o geralmente apenas 30% deste petr?leo ? extra?do e isto pode ser atribu?do, basicamente, a tr?s aspectos: alta viscosidade do petr?leo, geologia da forma??o e elevadas tens?es interfaciais entre os fluidos do reservat?rio. Os m?todos avan?ados de recupera??o envolvem a inje??o de um fluido ou de uma mistura de fluidos em um reservat?rio para atuar nos pontos onde o processo convencional n?o conseguiu atingir as taxas de extra??o desejadas. A inje??o de microemuls?o, considerado um m?todo avan?ado, tem por finalidade dessorver o ?leo da forma??o rochosa e obter um deslocamento eficiente da emuls?o de petr?leo. Dentro deste contexto, este trabalho foi realizado com dois objetivos principais: estudo dos par?metros que influenciam o sistema microemulsionado (tipo de tensoativo, cotensoativo, raz?o C/T e salinidade) e a avalia??o da efici?ncia de deslocamento do petr?leo com as microemuls?es que apresentaram estabilidade na regi?o rica em ?gua. Pelos par?metros analisados estipulou-se microemuls?es para serem submetidas ? etapa de recupera??o com composi??o: 25% ?gua, 5% querosene, 46,7% de n-butanol como cotensoativo e 23,3% de tensoativo BS ou SCO. Os testemunhos de arenitos Assu e Botucatu foram avaliados em ensaios de porosidade e permeabilidade posteriormente submetidos ?s etapas de satura??o com ?gua do mar e petr?leo, recupera??o convencional com ?gua do mar e avan?ada com as microemuls?es selecionadas. O arenito Botucatu apresentou os melhores par?metros f?sicos para a recupera??o, e a microemuls?o composta pelo tensoativo BS foi a que obteve maior efici?ncia de deslocamento (26,88%)

Orientador: Denis José Schiozer / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica e Instituto de Geociências / Made available in DSpace on 2018-08-26T09:48:51Z (GMT). No. of bitstreams: 1 Lamas_LuisFernandodeOliveira_M.pdf: 7621400 bytes, checksum: 2a0dfa71de9030f941d4937ac201a02e (MD5) Previous issue date: 2014 / Resumo: A injeção de polímeros é uma técnica de recuperação melhorada de óleo que consiste da mistura de polímeros à água para aumentar sua viscosidade e diminuir a razão de mobilidade entre o fluido deslocante e o fluido deslocado. A menor razão de mobilidade resulta em um melhor varrido areal e retardamento da irupção do fluido injetado nos poços produtores. O objetivo deste trabalho é estudar o efeito da injeção de polímeros no espaçamento ideal entre os poços pois se a influência for grande, a decisão pela injeção de polímeros deve ser tomada nos primeiros estágios da vida do campo. Para isso, este trabalho compara estratégias selecionadas para injeção de água às selecionadas para injeção de polímeros e realiza um teste com simulações cruzadas, onde polímeros são injetados para a estratégia selecionada para água e água é injetada na estratégia selecionada para polímeros. Os resultados mostram que, para o caso estudado, a diferença entre os espaçamentos dos poços não é muito grande e que o controle dos parâmetros operacionais é suficiente para compensar possíveis vantagens devido a posições diferentes dos poços. Dessa forma, para o exemplo e condições testadas, o campo pode ser desenvolvido considerando injeção de água e a decisão pela injeção de polímeros pode ser tomada nos estágios posteriores da vida do campo / Abstract: The injection of polymers is an improved oil recovery technique which consists on the mixture of polymers to the water to increase its viscosity and reduce the mobility ratio between the displacing and the displaced injection fluids. This smaller mobility ratio results in a better sweep efficience and a delay in the breakthrough time. The objective of this work is to study the effect of the polymer injection in the ideal spacing among the wells once if the influence is important, the decision for injecting polymers should be taken in the earlier stages of the field life. This work consists on the comparison of production strategies considering water and polymer flooding and tests, a crossed simulations, where polymers are injected in the strategy selected for water, and water is injected in the strategy selected for polymers. The results show that for the studied case, the difference among the well spacing for both strategies is not very important, and the control of the operational parameters is enough to compensate possible advantages due to different perforation schemes. It means that the field can be developed considering water injection and the decision for polymer flooding can be taken in the later stages of the field economic life / Mestrado / Reservatórios e Gestão / Mestre em Ciências e Engenharia de Petróleo

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"Safety is a value, not just a Priority" Geomechanically stable underground excavations require continuous assessment of rock mass behavior for maximizing safety. Optimizing pillar design is essential for preventing hazardous incidents and improving production in room-and-pillar mines. Maintaining regional and global stability is complicated for underground carbonate or stone deposits, where extensive fracture networks and groundwater flow become leading factors for generating unsteady ground conditions including karsts. A sudden encounter with karst cavities during mine advance may lead to safety issues, including ground collapse and outflow of unconsolidated sediments and groundwater. The presence of these eroded zones in pillars may cause their failure and poses a risk to the lives of miners apart from disrupting the pre-planned mining operations. A pervasive presence of joints and fractures plays a primary role in promoting structurally controlled failures in stone mines, which accelerates upon interaction with the karst cavities. The prevalent empirical and analytical approaches for pillar design ignore the geotechnical complexities such as the spatial density of discontinuities, karst voids, and deviation from the design during short-range mine planning. With the increasing market demand for limestone products, mining organizations, as well as enforcement agencies, are investing in research for increasing the efficiency of extracting valuable resources. While economical productivity is essential, preventing risks and ensuring the safety of miners remains the cardinal objective of mining operations. According to the Mine Safety and Health Administration (MSHA), since 2000, about 31% of occupational fatalities at all underground mines in the United States are caused due to ground collapse, which rises to 39% for underground stone mines. The objective of this study is to provide a reliable and methodological approach for pillar design in underground room-and-pillar hard rock mines for safe and efficient ore recovery. The numerical modeling techniques, implemented for a case study stone mine, could provide a pragmatic framework to assess the effect of karsts on rock mass behavior, and design future pillars detected with voids. The research uses data acquired from using remote sensing techniques, such as LiDAR and Ground-penetrating Radar surveys, to map the excavation characteristics. Discontinuum modeling was valuable for analyzing the pillar strength in the presence of discontinuities and cavities, as well as estimating a safe design standard. Discrete Fracture Networks, created using statistical information from discontinuity mapping, were employed to simulate the joints pervading the rock mass. This proposed research includes the calibration of rock mass properties to translate the effect of discontinuities to continuum models. Continuum modeling proved effective in analyzing regional stability along with characterizing the redistributed stress regime by imitating the excavation sequence. The results from pillar-scale and local-scale analyses are converged to optimize pillar design on a global scale and estimate the feasibility of secondary recovery in stone mines with a dominating discontinuity network and karst terrane. Stochastic analysis using finite volume modeling helped evaluate the performance of modified pillars to assist production while maintaining safety standards. The proposed research is valuable for improving future design parameters, excavation practices, and maintaining a balance between an approach towards increased safety while enhancing production. / Doctor of Philosophy / "The most valuable resource to come back out of a mine is a miner" – Anonymous. The United States accounted for 27% of the global limestone market share which was valued at US$58.5 billion in 2020 [148]. It is projected to reach a target of US$65.3 billion in 2027, growing even in midst of the COVID-19. As surface reserves deplete, much of the mineral demand gap is supplemented by mining underground deposits. Underground mines extract minerals from deep within the earth compared to surface mines. As a result, the miners experience a greater number of accidents in a constricted environment because of roof/tunnel collapse, fewer escape routes, ventilation, explosions, or inundation. According to the Mine Safety and Health Administration (MSHA), about 15% of all underground mine injuries in the US were caused by rockfalls since 1983. The majority of underground stone deposits are mined using the room-and-pillar mining method, which resembles a chessboard design where the light squares are mined, and the dark squares are left as rock pillars to support the tunnels. Limestone, a carbonate rock, contains a lot of fractures and joints (discontinuities). Erosion of rocks due to continuous water flow through the fractures leads to the formation of cavities known as karsts. Interaction of karsts with the prevalent fracture network increases rockfall risk during mining. The collapse of voids along with an inrush of filled rock-clay-water sludge can harm miners' lives, damage machinery, and stop further operations. Literature is scarce on topics that quantify the risk and disruption posed by these cavities in underground mines. Most rock classification systems cannot classify their effect because of the unpredictability and extensive analysis required. The objective of this research is to provide a reliable and methodological approach for designing pillars in underground hard rock mines for ensuring a safe working environment and efficient mineral recovery. This research starts with analyzing the strength of pillars, in which karst cavities were discovered while mining. The safety concerns often lead the miners to not excavate around the cavities and leave valuable resources unmined. Data from ground-penetrating radar and laser scanning surveys were used to characterize the voids and map the discontinuities. Discrete-element numerical modeling was used to simulate the pillars as an assembly of blocks jointed by the discontinuities. The simulation results help us understand the instability issues in the karst-ridden pillars and ways to improve upon the existing design. The findings were used to modulate the parameters for regional-scale models using finite volume modeling for less computationally intensive analyses and simulating rock as a continuum. The continuum models were highly effective in analyzing the instability issues due to the prevalent karstic network. This helps understand any alternative scenario that could have been implemented to optimize ore recovery while preventing risks. The results from the single pillar and regional analyses are combined to optimize pillar design on a global mine scale. This dissertation focuses on improving hazard mitigation in mines with unpredicted anomalies like karsts. Although this research is based on a specific mine site, it empowers the operators to explore the presented techniques to increase safety in all underground mines. The suggested methodology will help devise better strategies for handling instability issues without jeopardizing the mine operations. The primary motivation is to keep the underground miners safe from hazardous situations while fulfilling the secondary objective of maximizing mineral production.

Made available in DSpace on 2014-12-17T15:01:13Z (GMT). No. of bitstreams: 1 ValdirCRN.pdf: 131656 bytes, checksum: 4153e21d4042d68f4cdd2a9f2c14b5e9 (MD5) Previous issue date: 2007-08-31 / Petroleum is a complex combination of various classes of hydrocarbons, with paraffinic, naphtenic and aromatic compounds being those more commonly found in its composition. The recent changes in the world scenario, the large reserves of heavy oils and also the lack of new discoveries of large petroleum fields are indications that, in the near future, the oil recovery by conventional methods will be limited. In order to increase the efficiency of the extraction process, enhanced recovery methods are cited in applications where conventional techniques have proven to be little effective. The injection of surfactant solutions as an enhanced recovery method is advantageous in that surfactants are able to reduce the interfacial tensions between water and oil, thus augmenting the displacement efficiency and, as a consequence, increasing the recovery factor. This work aims to investigate the effects of some parameters that influence the surfactant behavior in solution, namely the type of surfactant, the critical micelle concentration (CMC) and the surface and interface tensions between fluids. Seawater solutions containing the surfactants PAN, PHN and PJN have been prepared for presenting lower interfacial tensions with petroleum and higher stability under increasing temperature and salinity. They were examined in an experimental apparatus designed to assess the recovery factor. Botucatu (Brazil) sandstone plug samples were submitted to assay steps comprising saturation with seawater and petroleum, conventional recovery with seawater and enhanced recovery with surfactant solutions. The plugs had porosity between 29.6 and 32.0%, with average effective permeability to water of 83 mD. The PJN surfactant, at a concentration 1000% above CMC in water, had a higher recovery factor, causing the original oil in place to be recovered by an extra 20.97%, after conventional recovery with seawater / O petr?leo ? uma combina??o complexa de v?rias s?ries de hidrocarbonetos, sendo as mais comumente encontradas as parafinicas, naft?nicas e arom?ticas. As recentes mudan?as no cen?rio mundial, as grandes reservas de ?leos pesados, bem como a escassez de descobertas de grandes campos de petr?leo, indicam que em um futuro pr?ximo a recupera??o de ?leo por m?todos convencionais ser? limitada. Para aumentar a efici?ncia do processo de extra??o, faz-se uso dos m?todos avan?ados de recupera??o para agir nos pontos onde o processo convencional mostrou-se pouco eficiente. A inje??o de solu??o de tensoativo, como um m?todo avan?ado de recupera??o mostra-se vantajosa, pois os tensoativos t?m a finalidade de reduzir as tens?es interfaciais entre a ?gua e o ?leo, ampliando a efici?ncia de deslocamento e, conseq?entemente, aumentando o fator de recupera??o. Este trabalho se prop?s a estudar os efeitos dos par?metros que influenciam as solu??es de tensoativos, como: tipo de tensoativo, concentra??o micelar cr?tica e tens?o superficial e interfacial entre os fluidos. As solu??es com ?gua do mar dos tensoativos PAN, PHN e PJN, por apresentarem menores tens?es interfaciais com o petr?leo e maior estabilidade com o aumento da temperatura e salinidade, foram estudadas em um aparato experimental para avalia??o do fator de recupera??o. Os testemunhos de arenito Botucatu foram submetidos a etapas de satura??o com ?gua do mar e petr?leo, recupera??o convencional com ?gua do mar e recupera??o avan?ada com solu??es de tensoativos. Os testemunhos apresentaram porosidade entre 29,6 e 32,0%, com permeabilidade m?dia efetiva ? ?gua de 83 mD. O tensoativo PJN, com concentra??o de 1000% acima da CMC apresentou maior fator de recupera??o, aumentando em 20,97% a recupera??o do ?leo original in place ap?s a recupera??o convencional com ?gua do mar

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