大巴山前陆盆地形成及演化与油气勘探潜力分析

根据野外地质调查、地震资料解释以及大量岩心分析化验等资料,探讨了大巴山前陆盆地的形成及演化,分析了油气勘探潜力。研究结果表明,大巴山前陆盆地形成始于燕山中幕,盆地演化经历了J₁-J₂¹陆内坳陷湖盆阶段、J₂²-J₃前陆盆地阶段、K₁N盆地萎缩阶段以及喜马拉雅期最终定型阶段。大安寨段和凉高山组两套优质烃源岩的有机质丰度高,有机质类型以Ⅱ₁型和Ⅱ₂型为主。侏罗系发育大安寨段、凉高山组自生自储型和下沙溪庙组下生上储型3套生储盖组合。有利勘探区带包括大巴山前冲断带、川北凹陷带和川中低隆起带。

Analysis on tectonic evolution and exploration potential in Dabashan foreland basin

On the basis of outcrop survey,seismic interpretation and a lot of coring data,the evolution and exploration potential of Dabashan foreland basin were analyzed. This foreland basin was formed in the mid-Yanshan cycle and underwent four stages including J₁—J¹₂depression stage, J²₂—J₃ foreland basin stage, K₁-N basin shrunk and final deformation of thrust-folded end in Himalayan period. In this basin, two sets of high-quality resource rocks developed in the Daanzhai Formation and Lianggaoshan Formation have high abundance of organic matters which mainly contain Ⅱ₁ type and Ⅱ₂ type kerogen. The favorable assemblages of source-reservoir-cap rocks in Jurassic include self-generated and self-reservoir type Daanzhai Formation and Lianggaoshan Formation as well as lower-generated and upper-reservoir typelower Shaximiao Formation. The favorable plays include the thrust belt in Dabashan area,sag in the north Sichuan province and uplift in the central Sichuan province.