Cores, drill-cuttings, and oil samples from the Sergipe-Alagoas basin were studied in detail to characterize and evaluate the source rocks of the area and correlate the oil with the probable source-rocks.

The content of organic matter was determined by conventional Leco analyses. The types of organic matter in each sample were determined qualitatively by visual microscopic examination. The thermal maturity was ascertained by light hydrocarbons (C₁ to C₄) analyses, organic extract composition, character of the C₁₅₊ saturated hydrocarbons, thermal alteration index (TAI) and, in a few places, by measurements of vitrinite reflectance.

The results of the study indicate that source rocks are present in stratigraphic sections belonging to three depositional cycles: nonmarine, transitional (evaporitic), and marine. Source rocks from each cycle yield oils of distinct character. Three oil systems were distinguished: (1) Barra de Itiuba/Serraria, (2) Carmopolis, and (3) Calumbi.

The source rocks of the Sergipe-Alagoas basin are of good quality but the total volume of hydrocarbons that might be expelled is probably not very large, since the source beds are relatively thin and probably discontinuous.

This study also indicates that entrapped hydrocarbons of the Sergipe-Alagoas basin have migrated short distances.

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