柴西乌南-绿草滩地区古近系下干柴沟组下段储盖组合与勘探潜力

Reservoir-seal associations and hydrocarbon potential of the lower member of the Palaeogene Xiaganchaigou Formation in the Wunan-Lucaotan region,western Qaidam Basin,Qinghai

运用层序地层学的理论和方法,综合钻井、测井和三维地震资料,在柴西乌南-绿草滩地区古近系下干柴沟组下段识别出两个层序界面,将其划分为1个长期基准面旋回(三级层序)LSC1和4个中期基准面旋回(四级层序)MSC1、MSC2、MSC3和MSC4。在等时地层格架约束下,详细分析了研究区储集层、盖层及储盖组合的发育规律与基准面旋回的内在联系,指出本区古近系下干柴沟组下段具有较大的油气勘探潜力。

The lower member of the Palaeogene Xiaganchaigou Formation in the Wunan-Lucaotan region, western Qaidam Basin, Qinghai comprises two sequence boundaries including one long-term base-level cycle （third-order sequence ） LSC1 and four medium-term base-level cycles （fourth-order sequence） MSC1, MSC2, MSC3 and MSC4 on the basis of cores, well logs and three-dimensional seismic data. The study of the reservoir-seal associations shows that the lower member of the Xiaganchaigou Formation may be highly prospective for hydrocarbon exploration. The favourable reservoir rocks consist of distributary channel sandstones and channel-mouth bar sandstones on the braided delta front in MSC3, where the composite tectonic-lithologic oil pools and lithologic oil pools are hosted.