鄂尔多斯盆地南部晚古生代沉积特征与天然气勘探潜力

Late Paleozoic sedimentary systems and gas potential in the south Ordos Basin

鄂尔多斯盆地南部地区是目前天然气勘探和研究程度较低的地区。在详细研究野外露头与钻井剖面的基础上,通过岩石学、沉积学分析以及古构造恢复等研究,阐明了晚古生代鄂尔多斯盆地南部地区有4个主要物源方向。指出该区太原组是一套以潮坪—潟湖—障壁岛—碳酸盐台地沉积为主的障壁海岸沉积,山西组沉积以曲流河、三角洲相为特征,下石盒子组发育辫状河、三角洲和湖泊相。鄂尔多斯盆地南部上古生界具有良好的烃源条件以及储盖组合,勘探潜力巨大。

The degree of natural gas exploration is lower in the south Ordos Basin, and there are poor understandings to geological conditions of gas reservoir forming and exploration potential in the area. Based on the analysis of field observations and well-data, four main provenances have been identified by means of lithologic properties, sedimentation analysis and paleo-structure reconstruction, etc. Taiyuan Formation belongs to a barrier shoreline system with the facies sequence of tide flat lagoon-barrler-carbonate platform. Shanxi Formation is a meandering river delta system, and Lower Shihezi Formation is a braid river-delta system. The gas exploration potential is great with high quality source rocks and good combinations of reservoir and cap rocks.