Characterization of crude oil and its fractions by thermogravimetric analysis

A system for evaluating a crude oil sample and calculates an indicative property of a gas oil or naphtha fraction of the crude oil sample without first distilling said gas oil or naphtha fraction, the system comprising:

• a thermogravimetric analyzer;
• a non-volatile memory device that stores calculation modules and data, the data including density of the crude oil sample and TGA data from an analysis of the crude oil sample as determined by the thermogravimetric analyzer;
• a processor coupled to the non-volatile memory;
• a first calculation module that retrieves the TGA data from the non-volatile memory device, calculates a crude oil thermogravimetric analysis index from a weighted mean of mass loss percentage versus heating temperature as indicated by the TGA data, and transfers the calculated crude oil thermogravimetric analysis index into the non-volatile memory;
• and
• a second calculation module that calculates the indicative property for the gas oil or naphtha fraction of the crude oil from a two-variable polynomial equation with predetermined constant coefficients developed using linear regression techniques, and that stores the indicative property into the non-volatile memory device;
• wherein the two variables of the two-variable polynomial equation are the crude oil thermogravimetric analysis index and the density of the crude oil sample.