Abstract: The volcanic rock reservoirs commonly occurred in domestic oil-gas exploration are significant complement of sandstone and carbonate reservoirs. According to the comprehensive information of geology, drill sample, well logging and seism, etc., the intrusive body of diabase in the area of Lin-9-Lin-3 in central uplift of Huimin sag is identified, its distribution pattern is found out and the condition of the diabase reservoir formation is analyzed in detail. The result shows that the formation and distribution of the diabase body are controlled by the occurrence of Linshang fault zone; the quality of diabase reservoir is improved during the active period of the fault. The fault zone acts as main pathway for oil-gas migrating into the volcanic reservoirs during the period of hydrocarbon accumulation and plays an important part in sealing the oil-gas reservoir during the ending period of active fault.

Key words: Huimin sag, uplift, diabase, reservoir, fault zone