准噶尔大型叠合盆地油气富集规律

Oil/gas Enrichment of Large Superimposed Basin in Junggar Basin

准噶尔盆地是我国油气资源增长的热点地区之一,具有典型的叠合盆地“多源多期多类型次生成藏”的油气聚集特征。通过应用叠合盆地研究中的关键技术,首次系统解剖了盆地的油气富集规律,提出盆地历史上发育了三期前陆盆地,其演化具有不同的油气地质意义。盆地叠合样式控制了油气的富集:①油气沿继承延变型的古隆起构造凸起部位聚集;②断裂对油气聚集的穿越式改造扩大了油气分布范围,增加了含油层系分布,造成了不同油气的混生成藏,同时也使油气分布特征复杂化;③不整合的间断变革使得其上的底砾岩和下面的风化壳是油气运移的良好通道;④早白垩世早期最大湖泛面控制下的储盖组合是中浅层岩性地层油气藏发育的重要层系。

Junggar Basin is one of key regions of petroleum resources increase in China, and is characterized by oil/gas accumulation of 'multi-source, multi-stage and multi-type secondary reservoir formation'.Through the study for key techniques of superimposed basin, it is put forwardthat the law of oil/gas enrichment in the basin,and three stages foreland basins developed in the basin evolution history ,giving the differentsignificance in petroleum geologic evolution. Basin superimposed style controls the law of oil/gas enrichment: (1)Oil/gas accumulated atpositive position of inheriting and extending plaeo-uplift;(2)Fault cut and reconstructed petroleum accumulation, as a result, the scope ofpetroleum distribution was enlarged, and the number of oil-bearing beds was increased, which resulted in oil/gas mixed-generating of differentsources and made the features of oil/gas distribution complicated;(3)Due to the interrupted change of unconformity, the bottom conglomerateover the unconformity and the weathering crust under the unconformity became the favorable pathways of oil/gas migration;(4) The reservoir-cap rock combination, controlled by early Cretaceous maximum lake flooding surface, might be important litho-stratum oil/gas reservoirsdeveloped in medium-shallow strata of the basin.