Abstract:

Based on the analysis of the geological conditions of hydrocarbon accumulation in the southern Songliao basin，the present fluid potential of Gaotaizi reservoir is calculated and the palaeo-fluid potential is recovered with the hydrocarbon accumulation dynamics systematic research as the core. The results show that the palaeo-present fluid potential of Gaotaizi reservoir is always high in the belt of Daan depression-Changling depression. The high-fluid potential belt constitutes the first-order separation trough in the southern Songliao basin. The fluid potential contours are simple to the west of the separation trough and complex to the east. Based on fluid potential field,1-2 allogenetic（authigenic）open hydrocarbon accumulation dynamic systems are divided in the west of the central separation trough，and 2-3 allogenetic（authigenic）opening (semi-closed) systems are divided in the east. Each hydrocarbon accumulation dynamic system constitutes a relatively independent of the aggregation unit. Applying the hydrocarbon accumulation dynamic system analysis results, combined with tectonic sedimentary evolution and reservoir fluid inclusion studies, the hydrocarbon charging and accumulation in the Gaotaizi reservoir is characterized.The various traps developed in the slope and near-depression uplift are conducive to the formation of various types of oil and gas reservoirs,because of their large fluid potential gradient.

Key words: the southern Songliao basin, Gaotaizi reservoir, hydrocarbon accumulation dynamics, fluid potential, hydrocarbon accumulation dynamic system, petroleum gas