Реферат: Wax appearance temperature (WAT) is critically important parameter characterized crude oil and other oil products (wax solution, fuels, bitumen, asphalt binders). The determination of WAT and other parameters at high pressure under such as gases: nitrogen, natural gas, and CO2, is essential to the development of the application of EOR methods based on gas injection flooding. Most of the available methods for determining WAT work at atmospheric pressure, and the study at high pressure in situ requires their significant modification. The FTIR spectroscopy method is quite widely used to study n-alkanes and phase transitions in their mixtures. However, there is no information on the use of the high-pressure FTIR spectroscopy for measuring WAT and phase transformations. At the same time, a variation of the method of ATR-FTIR spectroscopy has proven itself well in the study of systems in the in situ mode at high gas pressure. In situ ATR-FTIR spectroscopy was first used to study a solution of wax in n-dodecane at various pressures of CO2, nitrogen, and temperatures. It has been established that the ATR-FTIR spectroscopy can be used to reliably determine of WAT in the presence of CO2 and nitrogen. To determine WAT at high pressure, using traditional calculation methods that are based on changes in the rocking mode band of CH2 groups. In addition, it was found that the temperature dependence of the peak intensity of the spectral band characteristic of CO2 dissolved in the system exhibits a characteristic break. This can serve as an additional indicator of WAT, which increases the accuracy of the measurements and the reliability of determining the temperature of the onset of paraffin crystallization. Using the presented method, it was confirmed that with an increase in gas pressure, the temperature of the onset of paraffin crystallization decreases. This agrees well with the literature data on thermodynamic modeling of the phase behavior of n-alkane mixtures and experimental studies of differential scanning calorimetry.

Библиографическая ссылка: Shalygin A.S. , Morozov E.V. , Martyanov O.N.
New ATR-FTIR Spectroscopy Approach for Determination of Wax Appearance Temperature at High-Pressure Gas Conditions
V International Workshop «Thermal Methods for Enhanced Oil Recovery: Laboratory Testing, Simulation and Oilfields Applications» 03-05 Nov 2022