F. Montel

A simple correlation to evaluate binary interaction parameters of the Peng-Robinson equation of state: binary light hydrocarbon systems

Abstract Gao, G., Daridon, J.-L., Saint-Guirons, H., Xans, P. and Montel, F. 1992. A simple correlation to evaluate binary interaction parameters of the Peng-Robinson equation of state: binary light hydrocarbon systems. Fluid Phase Equilibria , 74:85-93 A simple correlation to evaluate binary interaction parameters k ij of the Peng-Robinson equation of state for light hydrocarbons mixtures is proposed, as a function only of critical temperature and compressibility factor. The method yields results with an accuracy bordering on that obtained with methods requiring specific adjustments for each binary mixture coefficient k ij .

Phase boundary measurement on a methane + decane + multi-paraffins system

Abstract Phase boundaries between homogeneous liquid phase and two-phase regions, both liquid-vapour and liquid-solid, and the phase boundary between the two-phase liquid - vapour region and the three-phase liquid - vapour - solid region were experimentally determined under pressure on the system methane + decane + heavy fraction using a full visibility sapphire cell. Measurements were performed on different mixtures made up of 90% of the binary mixture methane + decane (with a molar fraction of methane of about 50 %) and 10 % of a heavy fraction composed of various distributions of heavy normal paraffins centered around C 22 . The liquid-solid phase transition was investigated up to 45 MPa and fluid phase boundary was studied in the temperature domain from 293 K to 423 K.

Phase equilibria needs for petroleum exploration and production industry

Abstract Thermodynamic models are increasingly used to predict reservoir fluid behaviour, at all levels of exploration and production. However, their application in oil industry sectors is very different. As for exploration, modelling is based upon an uncertain composition, generated by a kinetic model or obtained by a heuristic approach. As for reservoir engineering, the access to fluid samples enables a stricter approach, with a series of problems specific to the following sequence: sampling XXX measurements and analysis XXX data processing XXX modelling. The results obtained from punctual samples shall then be extended to the whole reservoir. This is the subject of the fluid synthesis approach with a recent additional contribution from irreversible process thermodynamics, to take gravitation and thermal forces into account. Industrial problems are numerous at each step of the process and thus require the attention of scientists. Oil and gas surface processing is not dealt with. It is actually the domain best studied by thermodynamics specialists.

Fundamental statements about thermal diffusion for a multicomponent mixture in a porous medium

Abstract In a nonisothermal multicomponent system, there is a transport of matter by temperature gradients : this phenomenon is called thermal diffusion. Based on the thermodynamics of irreversible processes, this work : - provides a rigorous background to the study of the influence of gravity on the compositional variations with depth in hydrocarbon reservoirs, - proves that the theories of Haase (1969) and Kempers (1989) on “thermal diffusion” lie in the ideal case of “static thermal diffusion” : the coupling (thermodiffusion) coefficients are here equal to equilibrium quantities such as enthalpy or entropy, - states that in reality, the coupling coefficients do not reduce to pure thermostatic quantities : they are related to the microscopic motion of individual molecules, so that a kinetic theory is needed, - shows that, in a porous medium, the coupling coefficients should also depend on the characteristics of the medium.

Speed of sound in binary mixtures as a function of temperature and pressure

Abstract Ye S., Lagourette B., Alliez J., Saint-Guirons H., Xans P. and Montel F., 1992. Speed of sound in binary mixtures as a function of temperature and pressure. Fluid Phase Equilibria, 74:177-202. This paper reports experimental speed of sound measurements made at different pressures and temperatures for moderately (n-C6-n-C16) or markedly (C1-n-C16, CO2-n-C16) asymmetric binary mixtures at various concentrations. The results of comparative numerical tests of calculated speed of sound values, using six equations of state, are then reported. These tests used internal mixing rules (applicable to the specific coefficients of each equation of state) and external mixing rules (applicable to the critical coordinates of the components). The associations of equations of state and mixing rules which were found to be best able to describe the behaviour of the speed of sound in binary systems are demonstrated.

Petroleum characterization from ultrasonic measurement

Abstract Ultrasonic speed measurements have been performed under pressure on three reservoir fluids highly dissimilar in both composition and nature in order to identify the most appropriate equation of state — mixing rule combinations for predicting thermophysical properties of these fluids and also in order to examine the influence of the number of cuts and the mode of grouping on speed of sound calculation. The comparative analysis which was carried out between the sound speed measurements and the values generated by models, has pointed out that the predictions provided by the Lee–Kesler model are very satisfactory including at the highest pressure investigated (120 MPa). Moreover, the comparative study reveals no systematic degradation in reducing the description of the composition to a limited number of cuts.

Extension of the application of the Simha equation of state to the calculation of the density of n-alkanes-benzene and alkylbenzenes mixtures

Abstract In a previous article we proposed a method for evaluating interaction parameters between segments of n-alkane molecules (n-C 5 to n-C 24 ) in order to calculate the densities of these alkanes and their mixtures, in the liquid state, as a function of pressure and temperature, using the equation of state of Simha and Somcynsky. We have extended our previous method to mixtures of linear alkanes, alkylbenzenes and benzene. This paper first defines and evaluates all the parameters necessary for the description of interactions between the constituents of these different chemical families. The results of comparing experimental data (either obtained by ourselves or taken from the literature) with the calculated values obtained by the proposed method are then indicated. As in the case of n-alkane mixtures there is excellent agreement between these results. The average accuracy obtained was of the order of 0.25% over wide ranges of P and T .

Comparison with experimental data of ultrasound velocity in pure hydrocarbons calculated from equations of state

Abstract Ye S., Lagourette B., Alliez J., Saint-Guirons, H., Xans, P. and Montel, F., 1992. Comparison with experimental data of ultrasound velocity in pure hydrocarbons calculated from equations of state. Fluid Phase Equilibria , 74: 157-175. Compositional modelling of reservoir fluids constitutes an important activity in petroleum engineering, and this justifies the very considerable volume of research devoted to the development of equations of state. In this perspective, speed of sound measurement presents the advantage of making it possible to discriminate between thermodynamic models based on equations of state and mixing rules as a result of the high degree of reliability of the experimental data obtained. This paper compares the results of numerical comparisons between the experimental values for the speed of sound at different pressures and temperatures and the values calculated by means of six equations of state widely used in chemical engineering. The database used in these verifications includes values for the following pure substances: linear alkanes from n -C 3 to n -C 16 , benzene, toluene and cyclohexane.

Ultrasonic velocity in a hyperbaric reservoir fluid

This paper presents ultrasonic speed measurements in a hyperbaric reservoir fluid which is stored under 110 MPa and at 459.15 K. Comparisons between the data and the predictions of several equations of state, which are widely used in the petroleum industry, are also reported and discussed.

Accurate predictions for the production of vaporized water

The production of water vaporized in the gas phase is controlled by the local conditions around the wellbore. The pressure gradient applied to the formation creates a sharp increase of the molar water content in the hydrocarbon phase approaching the well; this leads to a drop in the pore water saturation around the wellbore. The extent of the dehydrated zone which is formed is the key controlling the bottom-hole content of vaporized water. The maximum water content in the hydrocarbon phase at a given pressure, temperature and salinity is corrected by capillarity or adsorption phenomena depending on the actual water saturation. Describing the mass transfer of the water between the hydrocarbon phases and the aqueous phase into the tubing gives a clear idea of vaporization effects on the formation of scales. Field example are presented for gas fields with temperatures ranging between 140{degrees}C and 180{degrees}C, where water vaporization effects are significant. Conditions for salt plugging in the tubing are predicted.