Organic matter in the oil and the residues after M. A. B. (Methanol-Acetone-Benzene) extraction of source-rocks, which were collected by drilling production tests from various nonmarine depositional layers in Qianan and Nongan area belonging to Jilin oilfield, were analyzed by Curie-point pyrolysis gas chromatography (pyrolysis-GC), elemental analysis, and infrared spectroscopy (IR). Genetic source studies have been performed on the basis of the correlation between the distribution of pyrolysates from kerogen and oils collected in various areas and depositional formations.
The results in this study indicated oil-source rock correlations as follows:
Samples from Nongan area: The n-alkanes distribution patterns in pyrolysates of the oils produced in K₁q⁴ formation were similar to those of the residues from the Jurassic K₁qn¹ source rocks. This fact indicates that K₁q⁴ oils had been generated from the Jurassic source rocks. This result is consistent with the conclusion of previous studies.
Samples from Qianan area: Although previous works concluded that the K₁q⁴ oils have genetic relationship whth K₁qn¹ formation source rocks, the n-alkanes distribution partterns in pyrolysates of K₁q⁴ oil were quite different from those of the residues prepared from K₁qn¹ source rocks. This result suggests that K₁q⁴ is not the source formation of the oils from K₁qn¹ and that another source formation forK₁q⁴ reservoir exists.