Optimum fluid placement is crucial for successful acid stimulation treatments of long horizontal wells where there is a broad variation of reservoir properties along the wellbore. Various methods have been developed and applied in the field to determine acid placement and the effectiveness of diversion process, but determining the injection profile during a course of matrix acidizing still remains as a challenge. Recently distributed temperature sensing technology (DTS) has enabled us to observe dynamic temperature profiles along a horizontal wellbore during acid treatments. Quantitative interpretation of dynamic temperature data can provide us with an invaluable tool to assess the effectiveness of the treatment as well as optimize the treatment through on-the-fly modification of the treatment parameters such as volume, injection rate and diversion method. In this study we first discuss how fluid placement can be quantified using dynamic temperature data. A mathematical model has been developed to simulate the temperature behavior along horizontal wellbores during and shortly after acid treatments. This model couples a wellbore and a near-wellbore thermal model considering the effect of both mass and heat transfer between the wellbore and the formation. The model accounts for all significant thermal processes involved during a treatment, including heat of reaction, conduction, convection. Then a fast and reliable inversion procedure is used to interpret the acid distribution profiles from the measured temperature profiles. We extend the real-time monitoring and evaluation of the acid stimulation treatment in horizontal wells to calculate the evolving skin factor as a function of time and location along the wellbore. As the skin factor is a reflection of the injectivity, it will indicate directly if the acid stimulation is effective and if diversion is successful. The approach to monitor the evolving skin along the lateral is to use a proper pressure transient model to calculate skin factor by integrating the inversion results of the temperature data (acid injection profile) with either surface or bottomhole injection pressure. This method can help engineers to optimize an acid stimulation in the field.

The increase in energy demand throughout the world has forced the oil industry to develop and expand on current technologies to optimize well productivity. Distributed temperature sensing has become a current and fairly inexpensive way to monitor performance in hydraulic fractured wells in real time by the aid of fiber optic. However, no applications have yet been attempted to describe or estimate the fracture parameters using distributed temperature sensing as the observation parameter. The Ensemble Kalman Filter, a recursive filter, has proved to be an effective tool in the application of inverse problems to determine parameters of non-linear models. Even though large amounts of data are acquired as the information used to apply an estimation, the Ensemble Kalman Filter effectively minimizes the time of operation by only using “snapshots” of the ensembles collected by various simulations where the estimation is updated continuously to be calibrated by comparing it to a reference model. A reservoir model using ECLIPSE is constructed that measures temperature throughout the wellbore. This model is a hybrid representation of what distributed temperature sensing measures in real-time throughout the wellbore. Reservoir and fracture parameters are selected in this model with similar properties and values to an unconventional well. However, certain parameters such as fracture width are manipulated to significantly diminish the computation time. A sensitivity study is performed for all the reservoir and fracture parameters in order to understand which parameters require more or less data to allow the Ensemble Kalman Filter to arrive to an acceptable estimation. Two fracture parameters are selected based on their low sensitivity and importance in fracture design to perform the Ensemble Kalman Filter on various simulations. Fracture permeability has very low sensitivity. However, when applying the estimation the Ensemble Kalman Filter arrives to an acceptable estimation. Similarly fracture halflength, with medium sensitivity, arrives to an acceptable estimation around the same number of integration steps. The true effectiveness of the Ensemble Kalman Filter is presented when both parameters are estimated jointly and arrive to an acceptable estimation without being computationally expensive. The effectiveness of the Ensemble Kalman Filter is directly connected to the quantity of data acquired. The more data available to run simulations, the better and faster the filter performs.

La red vial de Chile cuenta con 80.523 km, de los cuales sólo 17.245 km están pavimentados. Con el propósito de aumentar la red vial pavimentada a un menor costo, el Ministerio de Obras Públicas, a través de las Direcciones Regionales de Vialidad, han aplicado el uso de estructuras económicas de pavimentos granulares con coberturas asfálticas delgadas. Una de estas coberturas es el Doble Tratamiento Superficial (DTS) que hasta hoy sólo se ha usado en caminos con tránsito medio a bajo, no superando en la actualidad los 1 - 1,5 Millones de Ejes Equivalentes (MEE). El presente estudio se enmarca dentro del convenio suscrito entre el Laboratorio Nacional de Vialidad (LNV) y el Instituto Chileno del Asfalto (ICHAS) y consistió en verificar si este tipo de solución, responde de manera satisfactoria en caminos con mayores solicitaciones de tránsito. Para verificar el resultado de dicha experiencia, se eligió como base el contrato “Reposición de la Ruta 5 Norte, Sector Chañaral – Límite II Región”, de largo 22,75 km, que se ubica entre los paralelos 25º 56’ y 26º 20’Latitud Sur y meridiano 70º 30’ Longitud Oeste. Esta obra incluyó una capa de base granular con superficie de DTS convencional, sobre el pavimento existente. El desarrollo del trabajo consistió en establecer la condición original de la estructura de pavimento, para luego determinar y comparar la condición actual mediante mediciones de resistencia estructural, funcionalidad y durabilidad. Con esto, más una inspección visual, se logró definir la forma, magnitud y frecuencia del deterioro producido. En general, la estructura ha respondido satisfactoriamente frente a las solicitaciones de tránsito desde su puesta en servicio y momento actual, años 2004 y 2008 respectivamente. Los posibles daños presentados en este tipo de solución, se asocian a las condiciones ambientales, de drenaje, geometría y diseño estructural del pavimento. Los resultados en cuanto al comportamiento de la estructura sometida a tránsito medio a alto son promisorios. No obstante, para el futuro de esta investigación, se sugiere continuar con este seguimiento mediante una metodología genérica que incluye mediciones periódicas de su condición estructural y funcional.

Made available in DSpace on 2018-08-02T00:00:40Z (GMT). No. of bitstreams: 1 tese_10758_DISSERTAÇÃO LUIS CICERO.pdf: 5217516 bytes, checksum: 0fce34b82a55d9988fc6ed44eb25115f (MD5) Previous issue date: 2017-02-24 / O espalhamento Raman espontâneo é um efeito decorrente da interação de um campo eletromagnético com as moléculas do meio no qual o mesmo se propaga. Tal efeito possui forte dependência com a temperatura, encontrando portanto, aplicações em sensoriamento. Neste trabalho a modelagem deste efeito em fibras ópticas para aplicação em sensoriamento distribuído de temperatura é abordada. A princípio foi realizada uma revisão da literatura para levantar os parâmetros fundamentais e posteriormente as equações para gerar o efeito Raman espontâneo foram implementadas em software Matlab. Uma vez definido o modelo sensor proposto, simulações considerando diversos parâmetros e configurações foram analisadas com a finalidade de estudar como tais parâmetros afetam o desempenho do sensor aqui modelado. A partir do perfil de temperatura obtido, o desempenho do sensor foi verificado através do seu alcance, resolução espacial e de temperatura. Dessa forma, este estudo fornece princípios fundamentais de como dimensionar sensores distribuídos de temperatura em fibras ópticas baseados no espalhamento Raman espontâneo. Apresenta-se uma visão otimizada no desenvolvimento de sensores que atendam as necessidades da indústria, principalmente no monitoramento de grandes estruturas, onde o conhecimento de mudanças bruscas de temperatura é fundamental na preservação tanto das áreas monitoradas como principalmente da segurança de pessoas que trabalhem em tais locais.

One of the issues with multilateral wells is determining the contribution of each lateral to the total production that is measured at the surface. Also, if water is detected at the surface or if the multilateral well performance declines, then it is difficult to identify which lateral or laterals are causing the production decline. One way to estimate the contribution from each lateral is to run production Logging Tools (PLT). Unfortunately, PLT jobs are expensive, time-consuming, labor-intensive and involve operational risks. An alternative way to measure the production from each lateral is to use Distributed Temperature Sensing (DTS) technology. Recent advances in DTS technology enable measuring the temperature profile in horizontal wells with high precision and resolution. The changes in the temperature profile are successfully used to calculate the production profile in horizontal wells. In this research, we develop a computer program that uses a multilateral well model to calculate the pressure and temperature profile in the motherbore. The results help understand the temperature and pressure behaviors in multilateral wells that are crucial in designing and optimizing DTS installations. Also, this model can be coupled with an inversion model that can use the measured temperature and pressure profile to calculate the production from each lateral. Our model shows that changing the permeability or the water cut produced from one lateral results in a clear signature in the motherbore temperature profile that can be measured with DTS technology. However, varying the length of one of the lateral did not seem to impact the temperature profile in the motherbore. For future work, this research recommends developing a numerical reservoir model that would enable studying the effect of lateral inference and reservoir heterogeneity. Also recommended is developing an inversion model that can be used to validate our model using field data.

The inherent nature of distributed acoustic sensing technology is a direct result of two key components: optical fiber and the speed of light. Because the speed of light is constant and optical fiber is an isolated medium, combining the two creates a mechanism insulated from environmental interference that effectively “moves” at the speed of light. This process is most visible in the telecommunications industry where the technology transports large amounts of data over significant distances at very high speeds. The same factors that make optical fiber excellent for transporting data (high speed and low environmental interference) also make the technology very applicable for precise measuring applications. Because optical fiber is insulated, a change to the fiber will have a pronounced (measurable) effect. These measurable effects manifest themselves as changes in the amount of light that is reflected within the optical fiber. This change in reflected light can be measured and quantified to indicate both the specific location along the fiber where the change in reflection occurred and the magnitude of the change in reflection. Knowing both the location of the affected area and the extent to which the reflection changed allows for precise measuring and subsequently, educated inferences about what caused the changes initially. The ability of optical fiber to detect changes at myriad intervals over long distances has particular appeal for functions involving remote and hard to get to environments. Both of these conditions are inherent to the petroleum industry and provide substantial incentive for investigating DAS for oilfield applications.

Η ψηφιακή τομοσύνθεση στην τρισδιάστατη απεικόνιση μαστών, είναι μια μέθοδος ανακατασκευής οποιουδήποτε αριθμού τομογραφικών επιπέδων τυχαίου προσανατολισμού, στη βάση ψηφιοποιημένων προβολικών εικόνων της εξεταζόμενης περιοχής, που λαμβάνονται κατά την διάρκεια της περιστροφής του συστήματος ακτινολογική λυχνία-ενισχυτής εικόνας με κέντρο το ισόκεντρο του μηχανήματος και κατά το προεπιλεγμένο τόξο. Δυστυχώς, σε περιπτώσεις αυξημένης πυκνότητας μαστών, η ποιότητα των ανακατασκευασμένων επιπέδων επηρεάζεται από θόρυβο, λόγω των επιπροβαλλόμενων στοιχείων υπερκείμενων ή υποκείμενων επιπέδων. Το αντικείμενο που πραγματεύεται η εργασία, είναι η μελέτη διαφόρων τεχνικών επεξεργασίας των τομών, που θα μπορούσαν να αφαιρέσουν το θόρυβο από τα ανακατασκευασμένα επίπεδα και να βελτιώσουν την ποιότητά τους. Για αυτόν το λόγο, δημιουργήθηκαν τρία πειραματκά phantoms διαφορετικής πολυπλοκότητας, στα οποία προστέθηκαν δυσμορφίες που αντιπροσωπεύουν μικρές ασβεστοποιήσεις και μάζες χαμηλής αντίθεσης. Στη συνέχεια, υποβλήθηκαν στην προσομειωμένη απεικόνιση με ακτίνες Χ, προκειμένου να παραχθεί ένα σύνολο προβολικών εικόνων σε τόξο εύρους από -20° έως +20° κάθε 2°. Οι ακτινοβολημένοι όγκοι ανακατασκευάστηκαν μέσω του αλγόριθμου πολλαπλών προβολών (MPA), γραμμένο σε Matlab. Οι ανακατασκευασμένες φέτες έχουν πλάτος λιγότερο από 1mm, προκειμένου να ανιχνευθούν μικρές ασβεστοποιήσεις. Αναπτύχθηκαν και αξιολογήθηκαν πειραματικά δύο αλγόριθμοι για την περαιτέρω επεξεργασία των λαμβανόμενων τομών. Ο πρώτος είναι βασισμένος στην λογαριθμική μέθοδο αφαίρεσης δομών που βρίσκονται εκτός επιπέδου ενδιαφέροντος, συνδυάζοντας τεχνικές τονισμού της εικόνας. Η δεύτερη τεχνική εκτελεί το φιλτράρισμα της εικόνας, συγκρίνοντας τις τιμές των pixel, σε όλο τoν όγκο προς ανακατασκευή. Η ποιότητα της εικόνας καθορίστηκε μέσω της οπτικής αξιολόγησης των ανακατασκευασμένων επιπέδων καθώς και τον υπολογισμό του CNR. Και οι δύο αξιολογήσεις κατέδειξαν καλή διαχωριστική και αφαίρετική ικανότητα του τομογραφικού θορύβου. Το MPA σε συνδυασμό με τους προτεινόμενους αλγορίθμους αφαίρεσης θορύβου, μείωσε τον τομογραφικό θόρυβο στις ανακατασκευασμένες εικόνες και αύξησε το CNR. Περαιτέρω μελέτες θα περιλαμβάνουν την ανάπτυξη ενός γενικευμένου αλγορίθμου αφαίρεσης θορύβου που θα συνδυάσει τις προτεινόμενες δύο τεχνικές. / Digital tomosynthesis for breast imaging is a method of reconstructing any number of tomographic planes, by using a set of limited angle projections, acquired as the X-ray source moves in an arc around the breast. Unfortunately, in case of dense breasts, the quality of the reconstructed planes is affected by structured noise, due to blur from planes other than the fulcrum plane. The purpose of this project is to study different post-processing techniques that could remove the noise from the reconstructed planes and improve their quality. For this purpose, three software phantoms of different complexity with inserted abnormalities that represent small micro calcifications and low-contrast masses were created. Subsequently, they were subjected to x-ray imaging simulation in order to produce a set of projection images in the gantry arc from -200 to 200 every 20. The irradiated volumes were reconstructed with the Multiple Projections reconstruction Algorithm (MPA) written in Matlab. Reconstructed slices were with width of less than 1mm width, in order to detect the small microcalcifications. Two algorithms for removing unwanted structured noise were explored. The first one is based on the iterative logarithmic subtraction method of unrelated structures combined with image enhancement techniques. The second technique performs a filtering action based on a pixel intensity value comparison, throughout the phantom volume. Image quality was assessed by evaluation of the reconstructed planes in terms of both visual assessment and contrast to noise ratio (CNR). Both evaluations demonstrated good noise discrimination and elimination, followed by an improvement of the contrast and visibility of abnormalities in tomograms. The MPA followed by the proposed noise removal algorithms resulted in less noisy tomosynthesis images, higher CNR and feature contrast for both low- and high contrast details. Further studies include developing of a generalised noise removal algorithm that will combine the proposed two techniques.

Infiltration and inflow (I/I) are common problems in the foul sewer system. A method to detect I/I that is not commonly used in Sweden is DTS, Distributed Temperature Sensing. DTS is based on continuous measurements of temperature over a predetermined distance in the sewer system. The I/I is detected as temperature differences in the temperature data that is registered in the sewer system. The measurements often take place over a couple of weeks or months in the sewer system. The aim of this project was to review previous studies where DTS was used to detect I/I in foul sewers.  Data from a wastewater treatment plant in Umeå together with meteorological data were analysed to be able to visualize the problem of I/I and then suggest how DTS can be applied in Sweden. Both automated and visual analyses was performed to find if there were any relationships between wastewater temperature, wastewater flow and precipitation.   The outcome was that it is possible to apply DTS in the foul sewages to detect I/I. DTS seemed to be able to detect I/I in all types of sewage material, however it is dependent on that the I/I temperature differs from the temperature of the foul sewage water. It is an expensive technique but if it is meant to be used many times to analyse bigger areas it can be worth the costs. If larger areas are to be investigated, the costs for DTS and current methods are approximately the same.  At the wastewater treatment plant in Umeå, a slight relationship between wastewater temperature, wastewater flow and precipitation could be detected. The degree of dilution was calculated to 1,34 which means that about 25% of the sewage water is I/I. The conclusion from this was that I/I exists in the foul sewers in Umeå. The leakage points could not be located with this analysis. DTS could be a possible method to detect the leakage points of I/I in foul sewers. Unlike smoke tests, colouring and video-inspection of the sewers, DTS might be able to detect smaller leakage points. / Tillskottsvatten är ett vanligt problem i spillvattenledningsnätet. DTS, Distributed Temperature Sensing är en metod som inte är vanlig i Sverige för kontroll av spillvattenledningar. Tekniken bygger på kontinuerliga temperaturmätningar under en tidsperiod över en förutbestämd sträcka och registrerar temperaturavvikelser som kan uppstå i samband med inläckage av tillskottsvatten. Syftet med projektet var att granska tidigare utförda studier med DTS för att ta reda på hur tekniken kan användas för att lokalisera inläckage i spillvattenledningar. För att vidare illustrera problematiken med tillskottsvatten i spillvattennätet samt föreslå hur DTS kan appliceras i Sverige genomfördes en analys av mätdata på inkommande vatten till reningsverket på Ön, Umeå. Både visuella och automatiserade analyser genomfördes där tolkningar gjordes utifrån mätdata från reningsverket tillsammans med nederbörds- och lufttemperaturdata. En regressionsanalys genomfördes som automatiserad analys för att undersöka eventuella samband mellan spillvattentemperatur, spillvattenflöde och nederbörd. Projektet inleddes med en litteraturstudie där det utreddes hur DTS fungerar teoretiskt och praktiskt. Litteraturstudien visade att DTS är praktiskt möjligt att applicera i spillvattenledningsnätet för att leta inläckagepunkter för tillskottsvatten. Inläckage kan registreras som ökningar eller sänkningar i spillvattentemperaturen beroende på lufttemperaturen. Den är inte beroende av material på ledningarna men däremot är DTS beroende av att tillskottsvattnet är av annan temperatur än spillvattnet. Det är en dyr teknik men kan vara värt investeringskostnaderna om mätningar tänkt ske många gånger under längre perioder. Vid kontroll av större områden med hjälp av röktest kombinerat med färgning av vatten och filmning är kostnaderna ungefär de samma. Utifrån mätdatan från reningsverket och nederbördsdatan från Umeå universitet kunde vissa samband påvisas mellan spillvattentemperatur, spillvattenflöde och nederbörd. Ett visst samband kunde även urskiljas mellan spillvattentemperatur och spillvattenflöde. Utspädningsgraden av spillvattnet beräknades till 1,34 vilket innebär att cirka 25% av vattnet i spillvattenledningarna är tillskottsvatten. Slutsatsen som kunde dras utifrån detta var att tillskottsvatten existerar i spillvattenledningsnätet som leder till reningsverket på Ön i Umeå. Däremot kunde inga slutsatser dras för att säga var inläckage av tillskottsvatten sker. DTS skulle kunna appliceras i ledningsnäten för att undersöka närmare var inläckagepunkterna är och tillskillnad från rökning, färgning av vatten och filmning som används idag kan DTS sannolikt upptäcka fler typer av inläckage.

This diploma thesis analyzes a structure of spot optical sensors with longitudinal grid and multiple Bragg grating and possibilities of spot optical sensors use and implementation in the industry. Basic principles of light propagation through optical environment are described in the introduction part, followed by description of phenomena in optical fibers and sensors. The distribution of fiber optic sensors and the use of optic fiber in spot mode is described further. The optical sensor system is designed on the basis of analysis with description of its construction at the end of this work. A significant part is devoted to the analysis of longitudinal structures in the fiber in response to multiple Bragg gratings, their subsequent manufacture and suggestion of use in sensors industry.

Research based on translation expertise, which is also sometimes referred to as translation competence, has been a growing area of investigation in translation studies. These studies have not only focused on how translation expertise may be conceptualised and defined, but also on how this expertise is acquired and developed by translators. One of the key observations that arise from an overview of current research in the field of translation expertise is the prevalence of process-oriented methodologies in the field, with product-oriented methodologies used comparatively infrequently. This study is based on the assumption that product-oriented methodologies, and specifically the corpus-based approach, may provide new insights into translation expertise. The study therefore sets out to address the lack of comprehensive and systematic corpus-based analyses of translation expertise. One of the foremost concerns of corpus-based translation studies has been the investigation of what is known as the features of translated language which are often categorised as: explicitation, simplification, normalisation and levelling-out. The main objective of this study is to investigate the hypothesis that the features of translated language can be taken as an index of translation expertise. The hypothesis is founded on the premise that if the features of translated language are considered to be the textual traces of translation strategies, then the different translation strategies associated with different levels of translation expertise will be reflected in different frequencies and distributions of these features of translated language in the work of experienced and inexperienced translators. The study therefore aimed to determine if there are significant differences in the frequency and distribution of the features of translated language in the work of experienced and inexperienced translators. As background to this main research question, the study also investigated a secondary hypothesis in which translated language demonstrates unique features that are the consequence of various aspects of the translation process. A custom-built comparable English corpus was used for the study, comprising three subcorpora: translations by experienced translators, translations by inexperienced translators, and non-translations. A selection of linguistic operationalization’s was chosen for each of the four features of translated language. The differences in the frequency and distribution of these linguistic operationalization’s in the three sub corpora were analysed by means of parametric or non-parametric ANOVA. The findings of the study provide some support for both hypotheses. In terms of the translation expertise hypothesis, some of the features of translated language demonstrate significantly different frequencies in the work of experienced translators compared to the work of inexperienced translators. It was found that experienced translators are less explicit in terms of: formal completeness, simplify less frequently because they use a more varied vocabulary, use longer sentences and have a lower readability index score on their translations, and use contractions more frequently, which signals that they normalise less than inexperienced translators. However, experienced translators also use neologisms and loanwords less frequently than inexperienced translators, which is suggestive of normalisation occurring more often in the work of experienced translators when it comes to lexical creativity. These linguistic differences are taken as indicative of the different translation strategies used by the two groups of translators. It is believed that the differences are primarily caused by variations in experienced and inexperienced translators‟ sensitivity to translation norms, their awareness of written language conventions, their language competence (which involves syntactic, morphological and vocabulary knowledge), and their sensitivity to register. Furthermore, it was also found that there are indeed significant differences between translated and non-translated language, which also provides support for the second hypothesis investigated in this study. Translators explicitate more frequently than non-translators in terms of formal completeness, tend to have a less extensive vocabulary, tend to raise the overall formality of their translations, and produce texts that are less creative and more conformist than non-translators‟ texts. However, statistical support is lacking for the hypothesis that translators explicitate more at the propositional level than original text producers do, as well as for the hypothesis that translators are inclined to use a more neutral middle register. / MA (Language Practice), North-West University, Vaal Triangle Campus, 2013