Acoustic and mechanical response of reservoir rocks under variable saturation and effective pressure

We investigate the acoustic and mechanical properties of a reservoir sandstone saturated by two immiscible hydrocarbon fluids, under different saturations and pressure conditions. The modeling of static and dynamic deformation processes in porous rocks saturated by immiscible fluids depends on many parameters such as, for instance, porosity, permeability, pore fluid, fluid saturation, fluid pressures, capillary pressure, and effective stress. We use a formulation based on an extension of Biot's theory, which allows us to compute the coefficients of the stress-strain relations and the equations of motion in terms of the properties of the single phases at the in situ conditions. The dry-rock moduli are obtained from laboratory measurements for variable confining pressures. We obtain the bulk compressibilities, the effective pressure, and the ultrasonic phase velocities and quality factors for different saturations and pore-fluid pressures ranging from normal to abnormally high values. The objective is to relate the seismic and ultrasonic velocity and attenuation to the microstructural properties and pressure conditions of the reservoir. The problem has an application in the field of seismic exploration for predicting pore-fluid pressures and saturation regimes

The role of agency in the emergence and development of social innovations in rural areas. Analysis of two cases of social farming in Italy and the Netherlands

Social innovation is considered a relevant concept to tackle societal challenges and needs in rural areas and to promote smart, inclusive and sustainable growth. The characterising sector of rural areas is agriculture; therefore, the focus of this paper is on social innovation in the field of social farming. Among the many factors leading to the emergence and development of social innovation, agency has been considered relevant in the literature on transformability and transformative social innovation as it is the ability to turn contextual difficulties into opportunities for social innovation and for inclusive growth. This paper proposes an evaluation framework to assess the different dimensions of agency by triangulating quantitative with qualitative data and by using indicators. This paper adopts a case study approach, analysing two cases of social farming in Italy and the Netherlands. The results show that the social innovation idea and the resilience of the agency are among the most relevant dimensions for the emergence and development of social innovations. Finally, this paper discusses the three most relevant factors for agency to lead to social innovation: idea and embeddedness of the agency, transformability of the context through agencys resilience, and agency as catalyst for empowerment

CAPILLARY IMBIBITION TECHNIQUES USED TO CHARACTERIZE THESTRUCTURAL CHANGES IN MICROCRYSTALLINE CELLULOSE DUE TO WET AND DRY PROCESS

In this work we study the change on the wettability and solid properties of microcrystalline cellulose (Avicel PH101)after it was wet and dried, through drop penetration experiments in slightly compacted porous beds. We perform these experiments with water and a silicone oil, (Polidimethilsyloxane–PDMS) and we determine a dimensionless parameter that takes into account all the water penetration factors, including wettability and swelling. We consider three different scenarios, original MCC, and after one and two wetting and drying cycles. For each case we study the particle size effects by considering two subset samples SiA)25<φ<75μm and SiB)75<φ<125μm. We were able to determine, as it was expected, that PDMS penetration dynamics is not affected by the wetting–drying cycles but water is. The penetration rate goes down after cellulose was wet. Finally, we discuss how these behavior may affect the different processes where microcrystalline cellulose is used

PULSATILE FLOW OF VISCOELASTIC FLUIDS IN TUBES

In this study, we present an experimental investigation of the flow structure changes in non-Newtonian fluids subjected to periodic variable fluxes inside rigid-walled tubes. We employ a liquid mixture composed of water and polyacrylamide to account for various rheological properties. We obtain the velocity fields for each experimental case using the Particle Image Velocimetry (PIV) technique and we analyze their variations based on different properties of the pulsatile input signal. Reynolds numbers between 200 and 350 are considered, with a 10 % variation in amplitude

Evaluating the Impact of an Integrated Urban Design of Transport Infrastructure and Public Space on Human Behavior and Environmental Quality: A Case Study in Beijing

Urban transport infrastructure can result in the physical, psychological and environmental separation of neighborhoods, public spaces and pedestrian networks, leading to negative impacts on citizens’ daily commutes, social activities and the quality of the ecosystem. An integrated design of transport infrastructure and public space is beneficial for mediating these negative impacts. In this paper, we propose an integrated methodology, which combines urban design, computational scenario evaluation and decision-making processes, based on a conceptual model of human and ecological needs-driven planning. To evaluate the impacts of the road network and public space design on individual outdoor activities, travel behavior and air pollution, an agent-based model is demonstrated. This model is then applied to a case study in Beijing, leading to hourly traffic volume maps and car-related air pollution heat maps of a baseline road network-public space design

The Effects of the Planned High-Speed Rail System on Travel Times and Spatial Development in the European Alps.

One of the direct effects of introducing high-speed railway lines is a significant reduction in travel times between major cities. This is particularly relevant in mountain areas. It not only makes cities more easily reachable with more sustainable transport systems, but can also encourage different travel behavior and reduce environmental pressures on sensitive areas. A comprehensive analysis of the spatiotemporal effects of the introduction of high-speed railways in the Alpine arc has not yet been developed. To help fill this gap, this study uses multidimensional scaling and the geographical information system to illustrate the time–space compression. This term indicates the erosion of spatial and temporal distances, resulted in the areas of the Alps directly affected by the new railway lines. Six trans-Alpine high-speed railway lines are analyzed, comparing current and projected travel times by train. A time-based map is created to show the time-space compression in every transversal direction, particularly on the French and the Austrian side of the Alps. Implications in terms of local accessibility are also analyzed, focusing on the Autonomous Province of Bolzano/Bozen-South Tyrol. Finally, the paper discusses the importance of time-based maps for the understanding of sociospatial dynamics and the possible implications for spatial development

La nuova geografia delle Alpi: le conseguenze delle nuove linee ferroviarie ad alta velocità sul territorio (peri)alpino

Le infrastrutture ferroviarie alpine si stanno innovando profondamente, come testimonia la recente inaugurazione della galleria di base del Gottardo. Attualmente sono attivi diversi cantieri; altri, che prevedono ingenti investimenti economici, sono in programma nei prossimi anni. Con queste opere, si intendono migliorare i collegamenti ferroviari tra il nord e il sud delle Alpi, rendendo il trasporto su rotaia competitivo con quello su strada e favorendo così uno shift modale verso forme di trasporto meno impattanti, quali appunto la ferrovia. Il libro analizza gli interventi transnazionali più importanti e li contestualizza all’interno di una più ampia politica dei trasporti, che non include soltanto misure di infrastrutturazione, ma prevede anche altre misure integrative, di cui vengono evidenziati i rischi e le sfide attese. Tale politica non si riferisce alle sole Alpi, ma si estende alle aree limitrofe, dove sono localizzate realtà urbane di ordine superiore. In riferimento alle nuove linee ferroviarie ad alta velocità, vengono valutati le variazioni dei tempi di percorrenza e di accessibilità e gli impatti indiretti prodotti a livello territoriale. Grazie a specifiche mappe (basate non solo sulla rappresentazione della distanza fisica, ma anche della distanza temporale), è possibile capire l’incidenza delle nuove infrastrutture ferroviarie sul territorio, dando luogo ad una vera e propria “nuova geografia” delle Alpi

Velocidades de ondas Scholte en sedimentos marinos: sensibilidad a las propiedades geoacústicas y petrofísicas

En este trabajo se propone la implementación de un flujo de trabajo basado en modelos de física de rocas para la estimación de las propiedades elásticas de las rocas sedimentarias poco consolidadas de la corteza oceánica, el ajuste de velocidades sónicas compresionales, la predicción de las velocidades de corte y el cálculo y análisis de las curvas de dispersión de velocidades de ondas Scholte Vsh asociadas (para el modo fundamental y el primer modo superior). Para ilustrar el procedimiento se utilizaron datos de dominio público correspondientes a dos pozos del programa IODP en el Golfo de Bengala (océano Índico). Para la calibración del modelo se utilizan las mediciones de velocidad sónica compresional, densidad, porosidad, fracciones mineralógicas y espesores de la secuencia sedimentaria, además de las propiedades físicas del basamento basáltico, del agua de mar y su profundidad. A partir del modelo calibrado realizamos diversos análisis de sensibilidad de las velocidades de ondas Scholte y sus curvas de dispersión, en un rango de frecuencias que abarca las ondas sismológicas, el ruido sísmico y la sísmica de exploración, variando las propiedades geoacústicas y petrofísicas de las diferentes capas. La sensibilidad de Vsh ante cambios en la velocidad de onda S, como se espera, es mucho más marcada en comparación a la de onda P, teniendo correlación directa con ambas para el rango de frecuencias analizado. Con respecto a la porosidad, observamos alta sensibilidad de Vsh para ambos modos, exhibiendo correlación inversa entre ambas magnitudes. Del presente análisis se establece la factibilidad de invertir a partir de velocidades de ondas Scholte no sólo velocidades de corte y espesores (aplicaciones ya conocidas), sino también información petrofísica de interés para la caracterización del fondo marino.Facultad de Ciencias Astronómicas y Geofísica