关键词: 海拉尔盆地, 巴彦呼舒凹陷, 油气藏, 石油地质特征, 成藏条件, 油气勘探

Abstract: By applying theories and methods of basin analysis, sequence stratigraphy and reservoir-forming system, the reservoir-forming conditions of oil and gas are synthetically analyzed in Bayanhushu Sag,Hailaer Basin. Bayanhushu Sag is complex superimposed sag with several sub-sags, its structural framework is featured by zonary distribution in E-W direction and blocking distribution in N-S direction. Strata in Bayanhushu Sag can be divided into 3 first-order sequences, among which is further divided into 4 second-order sequences during faulted-depression period. Nantun Formation's shale, deposited in deep lacustrine facies and half-deep lacustrine faices of transgression system tract, has rich and favorable organic matter and large oil-generating potential, and is main source rocks in the sag. Sandstone and conglomerate reservoirs mainly exist in the sag. Nantun Formation, the main oil-bearing reservoir, has moderate porosity and medium-low permeability. Trap types in the sag include structural trap, lithologic trap and so on. According to previous exploration result, there are immature-low mature oil reservoirs as well as mature oil reservoirs in the sag, with a large exploratory potential. The types of oil reservoirs include structural, lithologic reservoirs and so on. Result of integrated evaluation shows that Haerdalang structural belt of centrol Bayanhushu Sag is favorable field for oil-gas migration and accumulation, and will be an important target region to realize the exploration breakthrough in Bayanhushu Sag.

Key words: Hailaer Basin, Bayanhushu Sag, oil-gas reservoir, petroleum geological feature, reservoir-forming condition, oil-gas exploration