Development and application of advanced thermodynamic molecular description for complex reservoir fluids containing carbon dioxide and brines

This thesis contains a study of the thermodynamic properties of complex reservoir fluids. The focus of this work is the development of an equation of state and molecular models to describe the phase behaviour of the different components of the reservoir fluids that may be encountered in the context of CO2 injection into geological formations suitable for storage, e.g., saline aquifers or depleted hydrocarbon reservoirs, together with that of mixtures of these components that may be encountered. The major constituents of these reservoir fluids are the injected gas (CO2, which may contain some impurities), alkanes and various other hydrocarbons from natural gas or crude oil, water and salts. The first task is to ensure that the method selected (the SAFT-VR Mie equation of state) to model those fluids can provide an accurate description of the simplest of the fluids encountered, CO2 and hydrocarbons. A crucial aspect of this concerns a detailed examination of the procedure for searching the highly degenerate model-parameter space to obtain the best models for each fluid. The suitability of the method is also assessed by studying other simple fluids, as a means to test the range of validity of the models developed. Once the method has been validated for a wide range of relatively simple fluids, the next step is to study more-complex fluids including, in particular, water. Water is ubiquitous in the systems of interest but is a notoriously difficult fluid to model accurately using simple models of the sort that are tractable for use in the context of equation-of-state modelling. The provision of a good model of water underpins a large part of the work and is accomplished only as a result of further development of the theory upon which the equation of state is based, involving not only its statistical-mechanical foundation but also lengthy numerical procedures to isolate the most physically reasonable application of the theory. Bearing in mind its simplicity, the resulting model for water, within the context of the refined theory, provides for a remarkably good representation of the thermodynamic properties of water and forms a highlight of the thesis. The remaining part of the work is the development of a framework in which to treat the ionic components of reservoir fluids. Following the implementation of a standard method to treat electrolyte solutions, the main goal of the thesis is achieved with the modelling of the phase equilibria of CO2-brine systems, demonstrating that the proposed method is a suitable tool for the study of complex reservoir fluids containing carbon dioxide and brines.Open Acces

Application of the SAFT-γ Mie group contribution equation of state to fluids of relevance to the oil and gas industry

Calculated data for all the figures presented in publication

Patrick Boucheron, Stéphane Gioanni (dir.), La Mémoire d’Ambroise de Milan. Usages politiques d’une autorité patristique en Italie (ve-xviiie siècle)

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Patrick Boucheron, Stéphane Gioanni (dir.), La Mémoire d’Ambroise de Milan. Usages politiques d’une autorité patristique en Italie (ve-xviiie siècle)

La patristique chrétienne occidentale a longtemps été uniquement l’objet de l’histoire de la théologie et des doctrines. Depuis quelques années, des travaux commencent à étudier la dimension sociale, politique et culturelle des figures patristiques dans les sociétés européennes aux époques médiévale et moderne. Ce volume en fait partie, en centrant son propos sur les représentations et les usages d’Ambroise à Milan dans la péninsule italienne entre le ve et le xviiie siècle, et apporte un ens..

Chapter Nicholas Trevet : le théologien anglais qui parlait à l’oreille des Italiens

The commentaries composed by the English theologian Nicholas Trevet at the beginning of the fourteenth century not only bear witness to his connections with Santa Maria Novella. They also testify to the importance of his contribution to the transfer of knowledge about Antiquity and the rebirth of antiquarianism in the Italian peninsula. This essay argues that Trevet’s Scholastic commentaries, presented as an expositio, met the need that Italian intellectuals had of a fuller understanding of classic literature, pagan mythology and Roman history

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The successful commercialisation of organic Rankine cycle (ORC) systems across a range of power outputs and heat-source temperatures demands step-changes in both improved thermodynamic performance and reduced investment costs. The former can be achieved through high-performance components and optimised system architectures operating with novel working-fluids, whilst the latter requires careful component-technology selection, economies of scale, learning curves and a proper selection of materials and cycle configurations. In this context, thermoeconomic optimisation of the whole power-system should be completed aimed at maximising profitability. This paper couples the computer-aided molecular design (CAMD) of the working-fluid with ORC thermodynamic models, including recuperated and other alternative (e.g., partial evaporation or trilateral) cycles, and a thermoeconomic system assessment. The developed CAMD-ORC framework integrates an advanced molecular-based group-contribution equation of state, SAFT-γ Mie, with a thermodynamic description of the system, and is capable of simultaneously optimising the working-fluid structure, and the thermodynamic system. The advantage of the proposed CAMD-ORC methodology is that it removes subjective and pre-emptive screening criteria that would otherwise exist in conventional working-fluid selection studies. The framework is used to optimise hydrocarbon working-fluids for three different heat sources (150, 250 and 350 °C, each with mcp = 4.2 kW/K). In each case, the optimal combination of working-fluid and ORC system architecture is identified, and system investment costs are evaluated through component sizing models. It is observed that optimal working fluids that minimise the specific investment cost (SIC) are not the same as those that maximise power output. For the three heat sources the optimal working-fluids that minimise the SIC are isobutane, 2-pentene and 2-heptene, with SICs of 4.03, 2.22 and 1.84 £/W respectively