Detailed analysis of fluid inclusions and its application in accumulation history research on Silurian reservoirs in Tazhong area, Tarim Basin

Based on the analysis of fluid inclusions including homogenization temperature, fluorescence spectroscopy, FT-IR spectroscopy, total scanning fluorescence spectroscopy (TSF) and GC-MS, the complicated accumulation process of Tazhong Silurian reservoirs was studied. The results show that three different types of hydrocarbon inclusions are developed in Tazhong Silurian reservoirs. The reservoirs have experienced three periods of hydrocarbon accumulation process. In the first period, the crude oil sourced from middle-lower Cambrian source rocks is accumulated in late Devonian and then damaged by tectonic uplift and erosion at the end of Devonian, forming the residual black bitumen. In the second period, the oil sourced from the middle-upper Ordovician source rocks is accumulated in late Permain. In the third period, the light oil & gas early accumulated in deeper reservoirs and mainly sourced from the middle-lower Cambrian source rocks is adjusted and migrated up through faults and then accumulated again in Silurian reservoirs in the Himalayan period. The current oil & gas accumulation in Silurian reservoirs is mainly a mixture of oil & gas accumulated in the second and third period.