Laurent Avaullee

Thermodynamic modeling for petroleum fluids I. Equation of state and group contribution for the estimation of thermodynamic parameters of heavy hydrocarbons

A group contribution method is proposed for estimating the critical properties and acentric factors of paraffins, naphtenes and aromatics with emphasis on extrapolating to very heavy compounds. Group contributions for sulfurized compounds were added to improve further applications in petroleum engineering or in any other domain. From the experimental normal boiling point, critical temperatures were correlated with a 0.6% average deviation on a set of 268 data and critical pressures with a 2.6% deviation on a 222 data set. The normal boiling points can be estimated without any experimental values. With this method, it was possible to correlate the normal boiling points of 641 hydrocarbons and sulfurized compounds with a deviation of less than 0.9%. From these estimated values, a 1% deviation was obtained at the critical temperatures and 2.8% at the critical pressures. The acentric factors of 160 compounds were correlated with a 6.5% deviation. With the proposed method, experimental vapor pressures were predicted using the Peng-Robinson equation of state for 125 compounds with a deviation of less than 5%. The results are compared with those obtained using other methods.

A new algorithm for enhanced oil recovery calculations

In order to test some algorithms currently available for enhanced oil recovery processes, the evolution of the thermodynamic Minimum Miscibility Pressure (MMP) with respect to the enrichment level of the injection gas by a solvent has been studied. Limitations of classical algorithms are evidenced and an alternative algorithm is proposed.

Thermodynamic modeling for petroleum fluids II. Prediction of PVT properties of oils and gases by fitting one or two parameters to the saturation pressures of reservoir fluids

This paper is devoted to the description of a method for modelling heavy cuts, using either a T.B.ce:simple-para. distillation or an advanced chromatography analysis method. Two sorts of reservoir fluids are defined depending on the advancement of the geochemical catagenetic reactions occurring during the history of the petroleum deposit. Given the existence of differences due to the geochemical history of fluids, two different thermodynamic characterizations may be computed from any given analytical information. One is generally more suitable for use with condensate gases and the other is more appropriate for calculating the physical properties of crude oils. The method presented here involves tuning one or two parameters to one of several saturation pressures of the reservoir fluid. This approach was tested on a data base including more than 50 reservoir fluids. In most cases, the PVT properties predicted using the above method were highly satisfactory.

Thermodynamic modeling for petroleum fluid III. Reservoir fluid saturation pressures. A complete PVT property estimation. Application to swelling test

Abstract This paper is the third one in a series in which a new strategy for modeling heavy petroleum cuts is proposed, with which the PVT properties of gas condensate and crude oils can be completely predicted using a classical one-fluid model with a cubic equation of state. In the second paper in this series, a new method of characterizing petroleum cuts was described. In was concluded that it was necessary to have at least one experimental saturation pressure in order to be able to calculate the PVT properties of a reservoir fluid with a good degree of accuracy. The third paper focuses on the development of a method which can be used to estimate the upper saturation pressure of reservoir fluids at about 100°C. The parameters used in the model were based on correlations involving more than 70 experimental saturation pressures. The method described in this paper, along with the characterization procedure described in the previous paper, makes it possible to completely calculate the PVT properties of a given reservoir fluid. Comparisons are made with other calculation methods described in the literature, and results obtained during gas injection experiments (swelling tests) are discussed.

A new approach in correlating the oil thermodynamic properties

A new compositional model is proposed to improve the prediction of phase behavior and physical properties of oil reservoir effluents. This work is based on a very classical and easy-to-handle cubic equation of state (EoS) coupled with a performing group contribution method devoted to the estimation of binary interaction parameters. The proposed model is compared to other published methods on the basis of laboratory data on real fluids, including pressure/volume/temperature (PVT) measurements and slim tube experiments. The method developed in this work shows enhanced results on a large range of pressure and temperature.