6,206 research outputs found

    A holistic approach to assessment of value of information (VOI) with fuzzy data and decision criteria.

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    The research presented in this thesis integrates theories and techniques from statistical analysis and artificial intelligence, to develop a more coherent, robust and complete methodology for assessing the value of acquiring new information in the context of the oil and gas industry. The classical methodology for value of information assessment has been used in the oil and gas industry since the 1960s, even though it is only recently that more applications have been published. It is commonly acknowledged that, due to the large number of data acquisition actions and the capital investment associated with it, the oil and gas industry is an ideal domain for developing and applying value of information assessments. In this research, three main gaps in the classical methodology for value of information are identified and addressed by integrating three existing techniques from other domains. Firstly, the research identifies that the technique design of experiments can be used in value of information for providing a holistic assessment of the complete set of uncertain parameters, selecting the ones that have the most impact on the value of the project and supporting the selection of the data acquisition actions for evaluation. Secondly, the fuzziness of the data is captured through membership functions and the expected utility value of each financial parameter is estimated using the probability of the states conditioned to the membership functions - in the classical methodology, this is conditioned to crisp values of the data. Thirdly, a fuzzy inference system is developed for making the value of information assessment, capturing the decision-making human logic into the assessment process and integrating several financial parameters into one. The proposed methodology is applied to a case study describing a value of information assessment in an oil field, where two alternatives for data acquisition are discussed. The case study shows how the three techniques can be integrated within the previous methodology, resulting in a more complete theory. It is observed that the technique or design of experiments provides a full identification of the input parameters affecting the value of the project, and allows a proper selection of the data acquisition actions. In the case study, it is concluded that, when the fuzziness of the data is included in the assessment, the value of the data decreases in comparison with the case where data are assumed to be crisp. This result means that the decision concerning the value of acquiring new data depends on whether the fuzzy nature of the data is included in the assessment, and on the difference between the project value with and without data acquisition. The fuzzy inference system developed for this case study successfully follows the logic of the decision maker and results in a straightforward system to aggregate decision criteria. Sensitivity analysis of the parameters of two different membership functions is made, reaching consistent results in both cases

    Propagating reaction fronts in moving fluids

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    La presente tesis tuvo como objetivo estudiar frentes de reacción modelados mediante la ecuación de Kuramoto-Sivashinsky sujetos a diferentes tipos de movimiento de fluido: flujo externo de Poiseuille, el cual es contrastado con el flujo de Couette, y flujo convectivo debido a la inestabilidad de Rayleigh-Taylor. En el primer caso, los frentes se propagan a favor o en contra de un flujo estacionario bidimensional entre dos placas paralelas que se conoce como flujo de Poiseuille. Para pequeñas distancias entre las placas, encontramos frentes estacionarios que pueden ser planos, simétricos o asimétricos, dependiendo de la separación de las placas y de la velocidad promedio del fluido externo. Adicionalmente, descubrimos que los frentes simétricos estables que se propagan en sentido opuesto al flujo simétrico externo se vuelven asimétricos al incrementar la rapidez del flujo externo. En el caso del flujo externo de Couette, el flujo es producido por el movimiento de dos placas paralelas en sentidos opuestos. Hallamos que la estabilidad y la forma de los frentes estacionarios dependen de la velocidad relativa entre las placas y de su separación. Estos parámetros desempeñan un papel importante, puesto que pueden convertir frentes inestables en estables. En el último caso, las inestabilidades en el frente producidas cuando un fluido más denso se encuentra encima de un fluido menos denso se conocen como inestabilidades de Rayleigh-Taylor y son causadas por la diferencia de densidades a través del frente bajo la acción de la gravedad. El frente describe la interfaz delgada que separa los fluidos de diferente densidad dentro de dos placas paralelas verticales; mientras que la convección causada por las fuerzas de flotación a través de la interfaz delgada determina el flujo debido a la inestabilidad de Rayleigh-Taylor. Para el estudio de los efectos del flujo externo sobre los frentes de reacción, primero obtuvimos los frentes y luego realizaremos un análisis de estabilidad lineal para determinar la estabilidad de los frentes bajo los tres tipos de movimiento del fluido. La forma de los frentes y sus respectivas regiones de estabilidad fueron contrastadas con los frentes en ausencia de flujo externo. Los resultados de la investigación fueron publicados en tres revistas internacionales arbitradas e indexadas: Physical Review E (2012), Chaos (2014), y European Physics Journal (2014). Adicionalmente, la tesis presenta resultados para frentes oscilantes y sus transiciones al caos debido a la interacción del frente de reacción con los flujos externos antes mencionados.Tesi

    Sensitivity analysis applied to fuzzy inference on the value of information in the oil and gas industry.

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    Value of information is a widely accepted methodology for evaluating the need to acquire new data in the oil and gas industry. In the conventional approach to estimating the value of information, the outcomes of a project assessment relate to the decision reached by following Boolean logic. However, human thinking is based on a more complex logic that includes the ability to process uncertainty. In value of information assessment, it is often desirable to make decisions based on multiple economic criteria which, if independently evaluated, may suggest opposite decisions. Artificial intelligence has been used successfully in several areas of knowledge, increasing and enhancing analytical capabilities. This paper aims at enriching the value of information methodology by integrating fuzzy logic into the decision-making process; this integration makes it possible to develop a human thinking assessment and coherently combine several economic criteria. To the authors’ knowledge, this is the first use of a fuzzy inference system in the specified knowledge domain. The methodology is successfully applied to a case study of an oil and gas subsurface assessment where the results of the standard and fuzzy methodologies are compared, leading to a more robust and complete evaluation. Sensitivity analysis is undertaken for several membership functions used in the case study to assess the impact that shifting, narrowing and stretching the membership relationship has on the value of information. The results of the sensitivity study show that, depending on the shifting, the membership functions lead to different decisions; additional sensitivities to the type of membership functions are investigated, including the functions’ parameters

    Fuzzy data analysis methodology for the assessment of value of information in the oil and gas industry.

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    To manage uncertainty in reservoir development projects, the Value of Information is one of the main factors on which the decision is based to determine whether it is necessary to acquire additional data. However, subsurface data is not always precise and is characterized by a certain level of fuzziness. In this paper, a model is formulated to assess the Value of Information in the oil and gas industry in cases where the data proposed to be acquired is imprecise. The methodology is based on the use of fuzzy data modelling and analysis aimed at providing decision support for oil field developers. An oilfield from North Africa is used as a case study to show how the methodology works. This work shows how the analysis can be utilized to reach financial decisions on the necessity of additional data acquisition

    A holistic approach to assessment of value of information (VOI) with fuzzy data and decision criteria.

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    Classical decision and value of information theories have been applied in the oil and gas industry from the 1960s with partial success. In this research, we identify that the classical theory of value of information has weaknesses related with optimal data acquisition selection, data fuzziness and fuzzy decision criteria and we propose a modification in the theory to fill the gaps found. The research presented in this paper integrates theories and techniques from statistical analysis and artificial intelligence to develop a more coherent, robust and complete methodology for assessing the value of acquiring new information in the context of the oil and gas industry. The proposed methodology is applied to a case study describing a value of information assessment in an oil field where two alternatives for data acquisition are discussed. It is shown that: i) the technique of design of experiments provides a full identification of the input parameters affecting the value of the project and allows a proper selection of the data acquisition actions, ii) when the fuzziness of the data is included in the assessment, the value of the data decreases compared with the case where data are assumed to be crisp; this result means that the decision concerning the value of acquiring new data depends on whether the fuzzy nature of the data is included in the assessment and on the difference between the project value with and without data acquisition, iii) the fuzzy inference system developed for this case study successfully follows the logic of the decision-maker and results in a straightforward system to aggregate decision criteria

    Dynamics in Times of Ionizing Radiation and Rainfalls in Tropical Region of Brazil

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    Low energy gamma rays and rainfalls were monitored each minute in the region around São José dos Campos, (230:10`S, 450:53`W) in Brazil, from March 7th to June 28th in 2017. In this period, it was possible to see the dynamic process that occurs between the presence of ionizing radiation (gamma rays) of low energy and the variation of rain intensity in (mm) / min in the same region. During this period, 12 major peaks of radiation intensity corresponding to 12 rains of high and low intensities were observed. This positive rainfall / radiation correlation is very noticeable in the tropical region of Brazil, which is certainly due to the presence of the decay of 238U uranium into radium 226Ra and arriving at the 222Rn radon with α emission particles and low energy gamma radiation. Therefore, the rain interferes in the presence of the local exhalation of the radon gas, causing the washing of this gas in the low atmosphere, increasing the intensity of radiation measured momentarily in that location. This work shows this dynamic measured in this interval in the year 2017, where there was rainy and dry weather in the place

    Dynamical complexity of discrete time regulatory networks

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    Genetic regulatory networks are usually modeled by systems of coupled differential equations and by finite state models, better known as logical networks, are also used. In this paper we consider a class of models of regulatory networks which present both discrete and continuous aspects. Our models consist of a network of units, whose states are quantified by a continuous real variable. The state of each unit in the network evolves according to a contractive transformation chosen from a finite collection of possible transformations, according to a rule which depends on the state of the neighboring units. As a first approximation to the complete description of the dynamics of this networks we focus on a global characteristic, the dynamical complexity, related to the proliferation of distinguishable temporal behaviors. In this work we give explicit conditions under which explicit relations between the topological structure of the regulatory network, and the growth rate of the dynamical complexity can be established. We illustrate our results by means of some biologically motivated examples.Comment: 28 pages, 4 figure

    Propuesta de mantenimiento productivo total (TPM) para mejorar la productividad de la empresa Lubriseng E.I.R.L Talara 2020

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    El presente trabajo de investigación titulado "Propuesta de mantenimiento productivo total (TPM) para mejorar la productividad de la empresa Lubriseng EIRL Talara 2020", es de tipo aplicado porque con toda la teoría que se obtuvo sobre el mantenimiento productivo total ayudó a incrementar la productividad en el área de mantenimiento automotriz de la empresa, esta investigación sugiere los aportes que pueden existir dentro de la sociedad para brindar una solución generadora de bienestar. Es Cuantitativo porque se utilizó la recolección de información o datos de forma cuántica, los cuales se representan mediante números mediante métodos o técnicas. Un diagnóstico de la situación actual de la empresa LUBRISENG E.I.R.L. Identificando lo siguiente: diagrama del diagnóstico del proceso de mantenimiento preventivo de los equipos de la empresa, la disponibilidad y confiabilidad de los equipos, la vida útil de los equipos, se determinó la metodología de mantenimiento productivo total a través del diagrama de Ishikawa, diagrama de Pareto, diagrama de diagnóstico del proceso de mantenimiento preventivo de vehículos con el fin de determinar la productividad mediante la recolección de información sobre el ingreso de vehículos que ingresaron a la empresa en los meses mencionados Donde se determinó la efectividad, a través de la información sobre mantenimientos preventivos de vehículos programados y ejecutados desde los meses de julio, agosto y septiembre. La eficiencia se determinó a través de la información programada de los tiempos útiles de mantenimiento preventivo del vehículo de los meses de julio, agosto y septiembre
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