Enhanced oil recovery by means of alkali injection. Behavior of the SARA fractions

Abstract

The presence of an alkali such as sodium hydroxide (NaOH) within a process of enhanced recovery of crude oil having certain acidity allows the formation of surfactants with the ability of enhancing the separation of the crude oil from the reservoir rock where it is adsorbed due to a change of wettability. This work focused on studying the effect of NaOH on the enhanced recovery, in terms of the SARA composition, of two different API gravity crude oils (38.5 and 24.1°) having different total acid number. The results showed the existence of acid components with high and low reactivity to NaOH in the crude oil, where the first group is responsible of the in-situ synthesis of the surfactant. Moreover, it was found that the utilization of the alkali improved the recovery of the SARA fractions for each crude oil, especially for the 24.1°API crude oil for which the recovery resulted twice or three times higher to the evaluated for the 38.5°API crude oil. Additionally, it was found that a minimum of 0.2?wt% of NaOH reduced up to 4 times the value of the interfacial tension between the crude oil and the brine, regardless of the type of crude oil.     

Physicochemical,thermal and sorption properties of nutritionally differentiated flours and starches

The aims of this work were to analyze physicochemical and thermal properties of ahipa and cassava flours and starches and to determine their water sorption isotherms and thermodynamic properties. Both flours are naturally gluten-free products, obtained by relatively simple procedures (grating or slicing). Ahipa flour gelatinized at lower temperature than cassava, indicating a better aptitude for cooking. Gelatinization temperatures of flours were higher than those of their starches. Water holding capacity of ahipa flours was significantly higher than those of cassava, leading the slicing process the highest values. Sorption isotherms were determined at 10, 20 and 30 °C. Experimental data were satisfactorily fitted using different mathematical models. Thermodynamic parameters associated with water adsorption process were calculated from GAB model, as well as the monolayer water content. All samples could be considered as products with an acceptable stability.     

Quantifying water quality and flow in multi-branched urban estuaries for a rainfall event with mass balance method

In this study, field observations were conducted after a heavy rainfall event in the Sumida and Shakujii rivers in Tokyo, Japan. The flow dynamics and fluxes of salt, suspended sediment (SS), and dissolved oxygen (DO) were investigated with the mass balance method. The fractions of fresh water and saltwater in seaward and landward flows were separated. The maximum salt flux in the Shakujii River was 53.8 kg/s during the flood tide, and those in the Sumida River were 680.3 kg/s at the upstream station and 703.7 kg/s at the downstream station. The trends of SS and DO fluxes were similar in both rivers. In the Shakujii River, the highest SS (3.1 kg/s) and DO (0.4 kg/s) fluxes appeared during the flood tide after rainfall. In the Sumida River, the maximum SS fluxes (6.1 and 6.3 kg/s at the upstream and downstream stations, respectively) and DO fluxes (1.15 and 1.21 kg/s at the upstream and downstream stations, respectively) appeared during the ebb tide. The mass balance method was used to estimate discharge, salinity, SS concentration, and DO concentration at a station with missing data. The results show that the estimated salinity and SS concentration had a significant correlation with the on-site observations, with correlation coefficients (R) of 0.950 and 0.835, respectively, but not for DO concentration (R = 0.638). The disparity between the computed and measured data may be explained by the differences in velocity, salinity, topography, sedimentation, and the presence of organic matter. The analysis based on the advective salt transport components found a lower salt flux per unit width in the Shakujii River (0.36 kg/(m·s)) in comparison with that in the Sumida River (2.88 kg/(m·s)). This indicates a higher probability for salt retention in the Shakujii River.     

Linking Contradictions and Laws of Engineering System Evolution within the TRIZ Framework

Tools and methods developed during the era of quality and optimization have shown their limitations and become inappropriate in the context of the requirements of innovation. Nowadays the need to rebuild design practices in enterprises is strongly felt both in terms of human skills and methodological expertise. In part, a way to face the innovation era's difficulties has been provided through the theory of inventive problem solving. This theory represents a significant breakthrough in driving problem statement and solving in a direction that is expressed through the idea that technical systems are driven by objective laws. A second postulate concerns the notion of contradiction, but so far only few contributions have addressed the relations between laws and contradictions. This paper, through a qualitative approach, presents a solution to this limitation and proposes a possible use of laws within the choice of the appropriate conflicting pair, prior to the use of any TRIZ solving techniques. Tests to observe the impact of the proposed approach were conducted in a French engineering ‘grande école’ during three semesters with 180 engineers. The contribution of this paper is twofold. On the one hand, there is a theoretical contribution to the theory of inventive problem solving. In addition, the proposed method offers especially TRIZ practitioners new ways for problem understanding and problem formulation.     

Achieving the Sustainable Development Goals: improving water services in cities affected by extreme weather events

Abstract

This article discusses how key risks from extreme weather events might affect progress towards meeting Sustainable Development Goals 6 and 11 in cities in developing countries. It outlines the magnitude of the existing shortfall in safe water and sanitation services, and how climate change will exacerbate existing problems. It argues that the performance of many governments thus far has lacked urgency and purpose. Unless governments in particular become more committed, with redoubled effort, the goals are unlikely to be achieved.