海拉尔盆地巴彦呼舒凹陷油气成藏条件

应用盆地分析、层序地层学以及成藏系统等理论和方法，对海拉尔盆地巴彦呼舒凹陷油气成藏条件进行了综合分析。结果表明，该凹陷是一个叠加的复合凹陷，具有东西分带、南北分块的构造格局;其地层可划分为3个一级层序，其中断陷期可进一步划分为4个二级层序;南屯组水进体系域的深湖—半深湖相泥岩有机质丰度高，母质类型好，生油潜力大，是凹陷的主要烃源岩;储层以砂岩和砂砾岩为主，主要含油储层南屯组为中孔中低渗储层；圈闭类型有构造、岩性等4大类。该凹陷中既有低熟—未熟油藏分布，也广泛分布着成熟油藏，勘探潜力巨大，其中凹陷中部的哈尔达郎等构造带是最有利的油气运聚成藏区带，是实现巴彦呼舒凹陷勘探突破的重要地区。

Reservoir-forming conditions in Bayanhushu Sag of Hailaer Basin

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 struetural 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.