THE COUPING RELATIONSHIP BETWEEN FLUID INCLUSIONS & HYDROCARBON FILLING OF TRIASSIC RESERVOIRS IN LUNAN UPLIFT OF TARIM BASIN

Lunnan uplift is the most abundant marine oil and gas complex petroliferous area in Tarim Basin. Industrial oil and gas flows have been found from Ordovician to Cretaceous, and all of them originate from the Middle-Upper Ordovician marine source rocks. Due to many structural tectonic cycles and active tectonic movement in the Tarim Basin resulted in the lateral differential distribution of oil and gas in large area and multiple vertical oil-bearing layers with complex and diverse oil and gas properties.. The Triassic oil and gas reservoir in Lunnan area of oil and gas properties，phase diversity，different regions of the pool-forming time differences. The same homogeneous temperature can correspond to two or more buried depths in a multi cycle superimposed basin. To reduce this multiplicity, In this study petrological observation, fluorescence spectra and fluid inclusion planes analysis were carried out on 63 samples in the study area. The homogenization temperature and trapping pressure of fluid inclusions were used to determine the age of hydrocarbon accumulation. Based on the determination of homogenization temperature of oil inclusions and their corresponding brine inclusions, bubble filling degree and oil composition of oil inclusions, the minimum capture pressure of oil inclusions was restored by PVTsim thermodynamic simulation software. The results show that the yellow-green fluorescence and blue-green fluorescence oil inclusions have similar fluorescence spectra and little difference in homogenization temperature, indicating that the two kinds of fluorescence oil inclusions do not reflect the existence of two stages of oil and gas filling in this area in the conventional sense, but that the early filling oil and gas was transformed by the late dry gas invasion. The reservoir forming period of the Lunnan Triassic clastic rock reservoir is the Himalayan period (13.8~4.9Ma).