IDENTIFICATION AND CLASSIFICATION OF HEAVY CRUDE OILS FROM THE WESTERN FLANK OF THE MIDDLE MAGDALENA VALLEY, COLOMBIA USING COMPOSITIONAL PARAMETERS MEASURED BY FT-ICR-MS

A set of crude oils from three fields in the Middle Magdalena Valley basin in Colombia (Abarco, Jazmin and Girasol) were classified using detailed geochemical techniques such as ultra-high resolution mass spectrometry based on the composition of NSO compounds. Twelve wellhead crude oil samples were analyzed by petroleomics (FT-ICR-MS) combining atmospheric pressure photo-ionization in positive mode (APPI (+)), and electrospray ionization in negative mode (ESI (-))

The relative abundances of different oxygen, sulfur and nitrogen compounds were obtained, as well as the Double Bond Equivalent (DBE) distributions. Considering representative saturation values and trends in DBE's, as well as the geographical distribution of the samples, coefficients of variation (CV) were determined in fourteen relative abundances and DBE distributions. For ESI (-), the classes N and O2 had low CV values for the samples of the Jazmin field, as well as for the ratios DBE 15/12 and DBE 9/12 of the class N. This allows identifying and classifying the oils of this field according these particular compositional relationships.

On the other hand, the ratio DBE 10/12 of the class S detected by APPI (+) show that the lowest CV values for the samples of the Girasol field, as well as the ratios DBE 5/12, DBE 9/12 and DBE 10/12 of the class N. In this way, such parameters allow discriminating the crude oils from the Girasol field.

Finally, the oils from Abarco field present the lowest CV values for the relative abundance of class S in APPI (+) and in the ratios DBE 13/12 of class N detected by ESI (-). The rest of the parameters do not seem to allow the identification of the crudes of this field, since the dispersion of the data is high, which coincides with the high variation in properties such as the viscosity and density.