Abstract: This paper studies the stratigraphic sequence of bioclastic limestone section of Bachu formation of Carboniferous in Bachu area of Tarim basin, based on which studies the bioclastic limestone reservoir characteristics and its distribution with core analysis data. Also, using fluid-inclusion analysis technique, this paper studies the hydrocarbon charging and accumulation history and its main controlling factors in this area. It is shown that this reservoir is characterized by grainstone and dolomite in lithology, pore, pore-fracture and fracture in reservoir space type, as well as main factors affecting the reservoir petrophysical property such as sedimentation, diagenesis and tectonic process. The most favorable reservoir could be distributed along and nearby Wellblock Mai-6 to Mai-4 in western Bachu area. The reservoir type is anticlinal reservoir and fractured reservoir, the former is dominant. There exist at least two periods of hydrocarbon charging and accumulation (Late Hercynian and Late Himalayan movements). The reservoir quality, tectonic evolution, fault and trap are the important factors controlling the hydrocarbon accumulation in this area.

Key words: Tarim basin, Buchu uplift, Carboniferous, carbonate rock, reservoir, hydrocarbon accumulation, main controlling factor