Chemical Aspects of Onshore Crude Oils from the Carmopolis Field, Sergipe-Alagoas Basin, Brazil: A Case Study on the Industrial Process for Water-Oil Separation

摘要

The importance of the Carmopolis field in Brazil for the exploration of onshore crude oil dates back to 1963. Currently still in operation, this is a major field, serving as a model for enhanced oil recovery tests. In this field, the differences in the physicochemical characteristics have awakened an interest in understanding the implications of the chemical composition of crude oils. Four blends of crude oil from this field were characterized using the SARA (saturates, aromatics, resins and asphaltenes) method and advanced methods such as energy dispersive X-ray fluorescence spectroscopy (EDX), laser desorption/ionization mass spectrometry (LDI-MS), infrared (IR), ultraviolet (UV), and thermogravimetric (TG) analysis. Of the four blends investigated, CEOL3 had the greatest affinity for water. The results for the SARA analysis did not reveal significant differences between the blends. The analysis of CEOL3 asphaltenes by IR spectroscopy revealed greater O-H stretching associated with water, and the TG indicated a more advanced state of thermal evolution compared with the other samples investigated in this study. Similarly, according to the EDX analysis, this oil sample had a greater affinity with produced water. Also, based on the UV analysis, the asphaltenes present in CEOL3 were of higher molecular mass compared with the other samples. Finally, the LDI-MS analysis of the blends showed a higher content of naphthenic acids and carbazoles in the CEOL3 sample which, together with the asphaltene content, is related to the stabilization of emulsions.