ANALYSIS OF EPISODIC POOL FORMATION IN DONGLING AREA, THE SONGLIAO BASIN

Primary organic inclusions in diagenetic minerals are widely used to determine the time of oil reservoir formation, oil expulsion, migration as well as hydrocarbon maturity. It is effective to indicate the timing and phases of hydrocarbons by integrating the analyses of the homogenization temperature and compositions of organic inclusions in diagenetic minerals with detailed modelling of paleotemperature and time-temperature burial history. As a case study, the authors examined the homogenization temperature and composition of organic inclusions in Dongling area, the Songliao Basin. The pool-forming history of reservoirs in this area we reconstructed by modelling burial and thermal history and analyzing homogenization temperature. The results indicated that there were at least three episodes of hydrocarbon pool formation and migration in the Early Cretaceous, occurring at about 85.8, 78.6 and 66 Ma respectively. The further compositional analysis of organic inclusions by Raman laser spectrum microprobe was consistent with the results from homogenization temperature analysis. Organic inclusion abundance and organic component content were lower, and the area underwent structure destruction in the late stages. These are unfavorable for present-day petroleum exploration.