藏北地区中上侏罗统接奴群沉积特征及油气远景

西藏北部改则－班戈地区出露的中上侏罗统接奴群是残余弧后盆地的滨浅海相陆缘碎屑沉积，具有完整的水进－水退沉积旋回。主要沉积相类型有碎屑浅海、高能滨岸、陆源碎屑潮坪、碳酸盐合地、扇三角洲等，向南部冈底期－念青唐古拉岛弧方向超覆，向北部羌塘板片与广阔碳酸盐台地相的佣钦错群过渡。接奴群是该区最有潜力的油气勘探目的层。广阔的浅海相泥页岩为主要的烃源岩，早期滨岸相粗碎屑岩是主要的潜在储集岩，有可能形成的油气藏类型包括超覆岩性油气藏和构造油气藏。

Sedimentary Features and Petroleum Geological Significance of the Jienu Group in Northern Tibet

The middle upper Jurassic Jienu Group,distributed widely along Gerze Baingoin area of northern Xizang, is terrigenous deposit of remnant retroarc basin with a complete transgressive regressive cycle. Its sedimentary types include such facies as open shallow sea, tidal flat ,carbonate platform,and fan delta facies. The Jienu Group overlaps toward the Gangdise Nyainqentanglha Arc,and is gradually transitional northward into wide carbonate platform facies of the Yongqincuo Group. The Jienu Group has great potential for oil and gas. Widespread mudstone of shallow sea facies is mainly hydrocarbon source rock; coarse clastic rock of littoral facies is potential reservoir rock; Hydrocarbon reservoirs likely to be found include the overlying lithologic oil reservoir and the structural oil reservoir.