柴达木盆地北缘含油气系统与油气勘探方向

柴达木盆地北缘侏罗系含油气系统具有巨厚的下侏罗统湖相泥岩和中侏罗统煤系地层。烃源岩有机质丰度高,有机质类型主要为Ⅱ-Ⅲ型,生烃期集中在喜山运动中晚期(E₃-N₁ )。本地区既有中生代古隆起,又有新生代构造运动形成的一系列构造圈闭(褶皱)和油气运移通道(断层),在侏罗系和第三系具有多套储盖组合。本区预测油气资源量达 10×108t,而探明油气储量仅为预测量的 3%,具有巨大的勘探潜力。冷湖一号至五号 (冷湖构造带西段 )勘探区带、南八仙-大红沟古隆起勘探区带及赛什腾山前勘探区带是今后柴达木盆地北缘最现实的三大有利勘探区带。

Strategy of Hydrocarbon Exploration in the Petroleum System of the Northern Qaidam Basin

Lower-Middle fresh lacustrine shale and coalmeasures with huge thickness have been found in the petroleum system of the northern Qaidam basin. These source rocks are characterized by high abundance of organic matter with mainly type Ⅱ-Ⅲ. The major oil and gas generation stage of the Jurassic source rocks is between theMiddle-Late episodes of the HimalayaMovement ( E₃ -2N₁ ). At that time, the existingMesozoic paleo-up lifts and the Cenozic folds and faults, which served as oilmigration routes and traps, greatly promoted the oil reservoir formation. In addition, multiple reservoir-cap compositions are confirmed in both the Jurassic and Tertiary strata. The estimated reserves of oil and gas are up to 1 billion ton of oil equivalent in the studied area. However, only about 3% of them have been found so far. Great potential for further hydrocarbon exp loration remains in this area. Three p referential targets for future hydrocarbon exp loration are selected, i. e. Lenghu No. 1 to No. 5 Trap, Nanbaxian2Dahonggou paleo up lift and the front of Saishiteng mountain