The Lower Paleozoic marine carbonate reservoirs in Tazhong83-Tazhong16 wellblock in Tazhong uplift within Tarim Basin have multiple oil/gas-bearing horizons

great differences in hydrocarbon properties and complicated oil/gas-water contact.On the basis of current hydrocarbon reservoir characteristics in the study area

in conjunction with the hydrocarbon accumulation process in Tazhong uplift

we analyzed the genetic mechanism of "the Himalayan gas invasion's decisive influence on current nature and distribution of hydrocarbon reservoirs" from the viewpoint of dynamic hydrocarbon migration

and drew three conclusions: (1) Hydrocarbon pools in the same horizon but different areas show the characteristics of "gas at both ends and oil in the middle" due to the existence of multiple faults connected with gas sources; (2) Hydrocarbon pools in the same area but at different horizons show the characteristics that "pure gas change progressively into condensate gas and finally into oil from bottom to top due to the limited gas charge along faults connected with gas sources and the heterogeneity of carbonate reservoirs; (3) Hydrocarbon pools in the same horizon and same area show abrupt change of oil/gas-water contact due to the local structural configuration and the existence of tight barriers.It is believed that the faults connected with gas source and unconformities that serve as the dominant hydrocarbon migration pathways control the direction of hydrocarbon migration

while the local structure configuration and tight barriers confine the extent of hydrocarbon migration.They both are the major factors controlling the nature of hydrocarbon reservoirs and the oil/gas-water contact.It is estimated that the deeper the exploration targets are and the closer they are to the faults connected with gas sources

the more favorable they are to gas exploration.