海拉尔盆地贝尔凹陷油气成藏模式与有利勘探方向

贝尔凹陷是海拉尔盆地富油凹陷之一,油气资源丰富,受多期构造运动改造,油气成藏条件复杂。研究表明,贝尔凹陷经历了"早、中、晚"三期成盆及南屯组末、伊敏组末两期改造的构造演化过程。每期"成盆与改造"对油气成藏起着关键性作用。有效烃源岩控制了油气分布范围;纵向上发育三套储盖组合。南屯组自生自储型组合为主要勘探层系;发育缓坡反向断阶带、复式箕状断陷间的断裂隆起带及保存条件好的小深洼槽三种成藏模式。油气成藏主控因素及富集规律的认识明确了贝西斜坡带南部、苏德尔特构造带南部及贝东洼槽群为下步重点勘探方向。

Hydrocarbon accumulation models and favorable exploration targets in Beier depression,Hailaer Basin

Beier depression is one of the most promising oil-bearing areas in Hailaer Basin with abundance of oil and gas resources.However,the reservoir forming conditions were complicated due to multi-period tectonic structural transformation.Researches suggested that Beier depression had experienced three-phases in basin formation,and two-period tectonic transformations （by end of the Nantun Formation and by end of Yimin Formation）,which played key roles in the process of hydrocarbon accumulation.The source rocks controlled the distribution of oil and gas.Vertically,there were three sets of reservoir-seal assemblages,while Nantun Formation,with its inherent hydrocarbon generation and accumulation conditions,was the major formation for exploration.There were three hydrocarbon accumulation models,the gently sloping antithetic fault bench,the uplift zone between duplex halfgraben fault depressions,and small deep sub-sags which provided good preservation conditions.Understandings on the controlling factors and rules of hydrocarbon accumulation provided favorable exploration targets of the south of Beixi slape belt the south of Sudeerte structural belt and sags of Beidong zone.