Abstract:
Gas chromatography(GC) and gas chromatography-mass spectrometry(GC-MS) are used to analyze the organic matter sources, sedimentary environment and thermal evolution degree of source rocks. The results show that the distribution of n-alkanes(m/z85) of source rocks from Hongshuizhuang Formation is dominated by front peak type unimodel. The main peak carbon is mostly nC
18, indicating the organic source is mainly lower organism. The tricyclic terpenes show a normal distribution with C
20 or C
23 as the main peak, and the ratio of C
24-tetracyclic diterpenes/C
26 tricyclic terpenes is 0.35-1.38, averagely 0.65, indicating that there is input of lower organism in Hongshuizhuang Formation. The steranes show the dominant C
27 sterane L-shape distribution, suggesting that the source of hydrocarbon generation material be lower aquatic organism. The Pr/Ph ratio is 0.16-0.85, with obvious phytane predominance, indicating a strong reducing environment and partially reducing environment. The gammacerane index(Ga/C
30H) is 0.06-0.66, averagely 0.21, reflecting the source rocks were formed in brackish water environment. The Sterane C
29-αββ/(αββ+ααα) is 0.26-0.46, averagely 0.42, showing the source rocks are mostly in the mature stage.