Application of Computational Fluid Dynamics to Near-Wellbore Modeling of a Gas Well

Well completion plays a key role in the economically viable production of hydrocarbons from a reservoir. Therefore, it is of high importance for the production engineer to have as many tools available that aid in the successful design of a proper completion scheme, depending on the type of formation rock, reservoir fluid properties and forecasting of production rates. Because well completion jobs are expensive, most of the completed wells are usually expected to produce as much hydrocarbon and as fast as possible, in order to shorten the time of return of the investment. This research study focused on the evaluation of well performance at two common completion schemes: gravel pack and frac pack. Also, the effects of sand production on well productivity and its associated erosive effects on the wellbore, downhole and tubular equipment were also a motivation in considering the inclusion of a decoupled geomechanics models into the study. The geomechanics-hydrodynamics modeling was done using a computational fluid dynamics (CFD) approach to simulate a near-wellbore model, on which diverse physical processes interact simultaneously, such as nonlinear porous media flow (Forchheimer formulation), turbulence kinetic energy dissipation, heterogeneous reservoir rock properties and particles transportation. In addition, this study considered a gas reservoir whose thermodynamic properties were modeled using the Soave-Redlich-Kwong equation of state. In general, this study is divided into: 1. Verification of a CFD simulation results against its corresponding analytical solution. 2. Analysis of well completion performance of each of the proposed completion schemes. 3. Effect of using Darcy’s law on the prediction of well completion performance. 4. Sand production and erosive damage analysis. The CFD approach used on this research delivered promising results, including pressure and velocity distribution in the near-wellbore model as well as three-dimensional flow patterns and effects of sanding on the wellbore integrity

Application of Pressure and Rate Transient Analyses to Stress-Sensitive Multi-Fractured Composite Systems and Compartmentalized Reservoirs

Pressure transient analysis (PTA) is one of the most robust and commonly interpretation tools available for reservoir characterization. Common applications of PTA include estimation of near-wellbore and reservoir properties, detection of reservoir limits and identification of depletion mechanisms. In addition, PTA allows the identification of sealing and leaky faults and the characterization of its properties, such as permeability and transmissibility hence direction of leakage within the fault. The purpose of this dissertation is to introduce the analytical solution for pressure-transient behavior for three novel reservoir models. First, we develop the analytical model of a multi-fracture horizontal well (MFHW) with pressure-dependent rock and fluid properties to study the impact of stress-dependent rock properties in composite unconventional systems. Second, we develop the analytical model for fluid-flow in a multi-well pad with three MFHWs in which wells can be interconnected through fracture hits. Lastly, we develop an analytical model of a compartmentalized reservoir with a segmenting fault in which fault permeability changes suddenly as a consequence of fault reactivation. Governing equations for fluid-flow are based on Darcy\u27s law. Pressure-dependent properties for the MFHW model are assumed to vary exponentially with local pressure-drawdown. Pressure-transient solution for each reservoir model is derived with the aid of advanced mathematical solution techniques, such as Laplace-Fourier transform and related numerical inversion, and iterative algorithms. Single-phase slightly compressible fluid-flow is considered for all reservoir models. Neither turbulence nor non-Darcy flow are considered in this work. Analytical solutions are presented as diagnostic plots and type curves. Analytical solutions were successfully validated against numerical simulation data. The resulting diagnostic plots and type-curves for well-test interpretation are presented and discussed for each case study. Various sensitivity analyses were carried out to examine the impact of several parameters of interest on pressure-transient behavior. In particular, we find that the effects of pressure-dependent fracture conductivity and stimulated reservoir properties, in conjunction, largely influence MFHW performance in stress-sensitivity formations. Likewise, we are able to detect and assess fracture hits by means of types-curves matching. Finally, we observe that fault reactivation can be detected on diagnostic plots as a sudden change in pressure-derivative response followed by a trend to attain late-time equilibrium

INTERSECTIONS OF ACTIVE MOBILITY: INTERDISCIPLINARY CONSTRUCTION OF PUBLIC SPACE ON THE UNIVERSITY CAMPUS

L'espai entre edificis ha estat assumit com a taula de treball del disseny urbà, però la llum guia prové del treball interdisciplinari que reuneix especialistes de l'arquitectura, les enginyeries o la psicologia ambiental (Steele, Luka y Guastavino, 2012). L'estudi de l'espai i la seva dialèctica no pot circumscriure's a cap disciplina en particular, sinó que necessita alimentar-se de visions i definicions complementàries, tot i que algunes vegades siguin necessàriament oposades. El present treball reconstrueix el procés dut a terme per un grup de professionals de diverses disciplines per a assolir l'objectiu comú de reconèixer el dret a l'espai (Leandro, 2009; Sorkin, 1992) de les persones que estudien, ensenyen o treballen al campus Rodrigo Facio de la Universidad de Costa Rica (UCR). Es fa un recompte de les dialèctiques que van donar origen al concepte i al pla UCR SALUDABLE, així com les lliçons apreses durant l'enriquidor procés de pensar l'espai des de diferents punts de vista.El espacio entre edificios ha sido asumido como mesa de trabajo del diseño urbano pero la luz guía proviene del trabajo interdisciplinario que conjunta especialistas de la arquitectura, ingenierías, psicología ambiental, etc. (Steele, Luka y Guastavino, 2012). El estudio del espacio y su dialéctica no puede ser acotado a alguna disciplina particular. Necesita nutrirse de visiones y definiciones complementarias aunque algunas veces necesariamente opuestas. El presente trabajo reconstruye el proceso llevado a cabo por un grupo de profesionales de distintas disciplinas para lograr el objetivo común de reconocer derecho al espacio (Leandro, 2009; Sorkin, 1992) de las personas que estudian, enseñan o trabajan en el campus Rodrigo Facio de la Universidad de Costa Rica (UCR). Se hace un recuento de las dialécticas que dieron origen, al concepto y plan de UCR SALUDABLE, así como las lecciones aprendidas en el rico proceso de pensar el espacio desde distintas ópticas.Space between buildings has been a traditional drawing desk for urban designers. That design is nurtured by collaborative insights from several areas as arquitecture, engineering, environmental psychology, and others (Steele, Luka y Guastavino, 2012). Space and its dialectics cannot be constrained to any particular discipline but nourished with different views, not always harmonious but sometimes divergent. This article elaborates on the practical experience developed by an interdisciplinary team on campus design at Universidad de Costa Rica. More than a discussion on traditional campus design, we analyse our common goal of recognizing the right to space for people studying, working, and teaching at Universidad de Costa Rica (Leandro, 2009; Sorkin, 1992). We discuss on the dialectics that gave way to the concept of HEALTHY UCR and lessons learned from the rich opportunity of thinking the space from different optics

Improved genetic algorithm for phase-balancing in three-phase distribution networks: A master-slave optimization approach

This paper addresses the phase-balancing problem in three-phase power grids with the radial configuration from the perspective of master–slave optimization. The master stage corresponds to an improved version of the Chu and Beasley genetic algorithm, which is based on the multi-point mutation operator and the generation of solutions using a Gaussian normal distribution based on the exploration and exploitation schemes of the vortex search algorithm. The master stage is entrusted with determining the configuration of the phases by using an integer codification. In the slave stage, a power flow for imbalanced distribution grids based on the three-phase version of the successive approximation method was used to determine the costs of daily energy losses. The objective of the optimization model is to minimize the annual operative costs of the network by considering the daily active and reactive power curves. Numerical results from a modified version of the IEEE 37-node test feeder demonstrate that it is possible to reduce the annual operative costs of the network by approximately 20% by using optimal load balancing. In addition, numerical results demonstrated that the improved version of the CBGA is at least three times faster than the classical CBGA, this was obtained in the peak load case for a test feeder composed of 15 nodes; also, the improved version of the CBGA was nineteen times faster than the vortex search algorithm. Other comparisons with the sine–cosine algorithm and the black hole optimizer confirmed the efficiency of the proposed optimization method regarding running time and objective function value

Synthesis, Structure, and Biological Assays of Novel Trifluoromethyldiazepine–Metal Complexes

A new series of CuII, NiII, CoII, and MnIII complexes have been synthesised from the (6Z)-6-(7-trifluoromethyl-1,2,3,4-tetrahydro-5H-1,4-diazepin-5-ylidene)cyclohexa-2,4-dien-1-one (HDZP) ligand. These complexes were characterised by elemental, spectroscopic (IR and UV-vis), and thermal analysis. The crystal structure of Cu-DZP was solved by X-ray diffraction methods. The complex crystallises in the monoclinic P21/c space group, with two molecules per unit cell. The crystal lattice is stabilised by different intra and intermolecular interactions. Hirshfeld surface analysis was employed to obtain additional information about interactions that are responsible for the crystal packing. Quantitative examination of the fingerprint plots indicated the dominant contribution of H⋯H and H⋯X (X = O, F) interactions in the crystal packing. In addition, C-H⋯chelate ring (CR) and C-H⋯π interactions are described in detail and evaluated using DFT calculations. The antibacterial properties and the mechanism of inhibition of the main bacterial resistant mechanism, the biofilm, of the metal complexes and free ligand were investigated. [Mn(DZP)3]·2H2O was the most active complex against the Pseudomonas aeruginosa biofilm formation with an inhibition of 40 %. However, none of the complexes inhibit more than 25 % of the Gram negative bacteria microbial development. The most meaningful result was the bactericidal effect of [Co(DZP)2(H2O)2]·2H2O against the Gram positive bacteria, Staphylococcus aureus, which inhibits the bacterial development and significantly reduces the biofilm formation at low concentration.Fil: Rocha, Mariana. Universidad Nacional de Tucumán; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto de Química del Noroeste. Universidad Nacional de Tucumán. Facultad de Bioquímica, Química y Farmacia. Instituto de Química del Noroeste; ArgentinaFil: Echeverría, Gustavo Alberto. Facultad de Ciencias Exactas, Universidad Nacional de la Plata; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Física La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Física La Plata; ArgentinaFil: Piro, Oscar Enrique. Facultad de Ciencias Exactas, Universidad Nacional de la Plata; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Física La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Física La Plata; ArgentinaFil: Jios, Jorge Luis. Facultad de Ciencias Exactas, Universidad Nacional de la Plata; ArgentinaFil: Molina, Rocío Daniela Inés. Universidad Nacional de Tucumán; Argentina. Universidad Nacional de Tucumán. Instituto de Biotecnología Farmacéutica y Alimentaria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto de Biotecnología Farmacéutica y Alimentaria; ArgentinaFil: Arena, Mario Eduardo. Universidad Nacional de Tucumán; Argentina. Universidad Nacional de Tucumán. Instituto de Biotecnología Farmacéutica y Alimentaria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto de Biotecnología Farmacéutica y Alimentaria; ArgentinaFil: Ulic, Sonia Elizabeth. Facultad de Ciencias Exactas, Universidad Nacional de la Plata; Argentina. Universidad Nacional de Luján; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Química Inorgánica "Dr. Pedro J. Aymonino". Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Centro de Química Inorgánica "Dr. Pedro J. Aymonino"; ArgentinaFil: Gil, Diego Mauricio. Universidad Nacional de Tucumán; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto de Química del Noroeste. Universidad Nacional de Tucumán. Facultad de Bioquímica, Química y Farmacia. Instituto de Química del Noroeste; Argentin

A study about the microstructure behaviour of coffee and chlorogenic acids during roasting a case study in “tecnoparque agroecológico yamboró”

Las variedades de café arábica (Coffea arabica L.) presentan excelente calidad con sabores suaves, aromas intensos y acidez agradable; cualidades dadas por la genética de la planta y los componentes químicos naturales del grano de café que varían según su producción, procesos en las fincas, almacenamiento, comercialización, tostión y preparación. El presente estudio se realizó con granos de café almendra variedad Colombia cultivada en el municipio de Pitalito (Huila), a partir del cual se observó una relación entre el contenido de ácidos clorogénicos totales determinado por espectroscopia UV y la microestructura del grano observada por Microscopia Electrónica de Barrido, y analizando los poros formados con respecto a dos tratamientos de tostión a los que fueron sometidos.The varieties of Arabica coffee (Coffea arabica L.) have excellent quality due to their soft flavors, intense aroma and pleasant acidity. These qualities are produced by the plant genetics and the natural chemical components of the coffee bean that vary according to their production, processing in farms, storage, marketing, roasting and preparation. This study was performed using Colombia variety almond coffee beans grown in Pitalito (Huila), from which a relationship between the content of total chlorogenic acids determined by a UV spectroscopy and the bean microstructure was observed; this relationship was remarked in an electron microscopy scanning. The pores formed by the two different roasting treatments they were put through were analyzed as well.na8 página

Energy Estimation of Cosmic Rays with the Engineering Radio Array of the Pierre Auger Observatory

The Auger Engineering Radio Array (AERA) is part of the Pierre Auger Observatory and is used to detect the radio emission of cosmic-ray air showers. These observations are compared to the data of the surface detector stations of the Observatory, which provide well-calibrated information on the cosmic-ray energies and arrival directions. The response of the radio stations in the 30 to 80 MHz regime has been thoroughly calibrated to enable the reconstruction of the incoming electric field. For the latter, the energy deposit per area is determined from the radio pulses at each observer position and is interpolated using a two-dimensional function that takes into account signal asymmetries due to interference between the geomagnetic and charge-excess emission components. The spatial integral over the signal distribution gives a direct measurement of the energy transferred from the primary cosmic ray into radio emission in the AERA frequency range. We measure 15.8 MeV of radiation energy for a 1 EeV air shower arriving perpendicularly to the geomagnetic field. This radiation energy -- corrected for geometrical effects -- is used as a cosmic-ray energy estimator. Performing an absolute energy calibration against the surface-detector information, we observe that this radio-energy estimator scales quadratically with the cosmic-ray energy as expected for coherent emission. We find an energy resolution of the radio reconstruction of 22% for the data set and 17% for a high-quality subset containing only events with at least five radio stations with signal.Comment: Replaced with published version. Added journal reference and DO

Measurement of the Radiation Energy in the Radio Signal of Extensive Air Showers as a Universal Estimator of Cosmic-Ray Energy

We measure the energy emitted by extensive air showers in the form of radio emission in the frequency range from 30 to 80 MHz. Exploiting the accurate energy scale of the Pierre Auger Observatory, we obtain a radiation energy of 15.8 \pm 0.7 (stat) \pm 6.7 (sys) MeV for cosmic rays with an energy of 1 EeV arriving perpendicularly to a geomagnetic field of 0.24 G, scaling quadratically with the cosmic-ray energy. A comparison with predictions from state-of-the-art first-principle calculations shows agreement with our measurement. The radiation energy provides direct access to the calorimetric energy in the electromagnetic cascade of extensive air showers. Comparison with our result thus allows the direct calibration of any cosmic-ray radio detector against the well-established energy scale of the Pierre Auger Observatory.Comment: Replaced with published version. Added journal reference and DOI. Supplemental material in the ancillary file