Characterization of crude oil and its fractions by fourier transform infrared (ftir) spectroscopy analysis
AssigneeSaudi Arabian Oil Company
InventorsOmer Refa Koseoglu, Adnan Al-Hajji, Amer A. Al-Tuwailib
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Abstract
A system and a method are provided for calculating the cetane number, pour point, cloud point, aniline point, aromaticity, and/or octane number of a gas oil or naphtha fraction of a crude oil from the density and Fourier transform infrared spectroscopy (FTIR) of a sample of the crude oil, without first distilling the crude oil into the gas oil or naphtha fraction.
Claims22
A system for evaluating a crude oil sample and calculating at least one indicative property of a naphtha or gas oil fraction of the crude oil sample without first distilling said naphtha or gas oil fraction, wherein the at least one indicative property is selected from cetane number, pour point, cloud point, aniline point, aromaticity, and octane number, the system comprising:
- a non-volatile memory device that stores calculation modules and data, wherein the calculation modules include at least a first calculation module and a second calculation module, and wherein the data includes density of the crude oil sample and Fourier transform infrared spectroscopy data derived by an analysis of the crude oil sample by a Fourier transform infrared spectrophotometer, wherein the spectroscopic data is indicative of transmittance values at predetermined increments between a predetermined range for the crude oil sample;
- and
- a processor coupled to the non-volatile memory;
- wherein the first calculation module, upon being executed by the processor, retrieves the Fourier transform infrared spectroscopy data from the non-volatile memory, that calculates a crude oil Fourier transform infrared spectroscopy index value of the fraction from the transmittance values of the spectroscopy data, and that transfers the calculated Fourier transform infrared spectroscopy index into the non-volatile memory;
- and
- wherein the second calculation module, upon being executed by the processor, calculates the at least one indicative property for the fraction of the crude oil from a two-variable polynomial equation with predetermined constant coefficients developed using linear regression techniques, and stores the at least one indicative property into the non-volatile memory device;
- wherein the two variables of the two-variable polynomial equation are the Fourier transform infrared spectroscopy index and the density of the crude oil sample.
A method for evaluating a crude oil sample and calculating at least one indicative property of a naphtha or gas oil fraction of the crude oil sample without first distilling said naphtha or gas oil fraction, wherein the at least one indicative property is selected from cetane number, pour point, cloud point, aniline point, aromaticity, and octane number, the method comprising;
- receiving the density of the crude oil sample and storing it into non-volatile memory of a computer;
- receiving Fourier transform infrared spectroscopic data derived by an analysis of the crude oil sample by a spectrophotometer, wherein the spectroscopic data is indicative of transmittance values at predetermined increments between a predetermined range for the oil sample, and storing the spectroscopic data into the non-volatile memory;
- using a processor of the computer that is coupled to the non-volatile memory to calculate a crude oil Fourier transform infrared spectroscopy index value of fraction from the transmittance values;
- and
- using the processor to calculate and record into the non-volatile memory the at least one indicative property for the naphtha or gas oil fraction of the crude oil from a two-variable polynomial equation with predetermined constant coefficients developed using linear regression techniques;
- wherein the two variables of the two-variable polynomial equation are the Fourier transform infrared spectroscopy index and the density of the crude oil sample.
Dependencies are inferred from the claim text.