Method to determine API gravity of sulfur-rich marine oils using aromatic compound chemistry

Abstract

A method of determining an API gravity of a crude oil includes obtaining a reservoir sample containing the crude oil, separating an aromatic fraction from the reservoir sample, analyzing the aromatic fraction using a gas chromatography mass spectrometry (GC-MS) instrument, determining peak areas and a ratio of 4-methyldibenzothiophene and 1-methyldibenzothiophene, and determining the API gravity of the crude oil in the reservoir sample using an empirical correlation between API gravity and the ratio of 4-methyldibenzothiophene to 1-methyldibenzothiophene. A method of determining productivity of a region of a reservoir includes determining an API gravity of a crude oil in the sample from the region of the reservoir using an empirical correlation between API gravity and the ratio of 4-methyldibenzothiophene to 1-methyldibenzothiophene, and based on the API gravity of the sample, determining the productivity of the region of the reservoir.

Dependencies are inferred from the claim text.