Quantitative Evolution of Paleostructure at the Bottom of the Yanchang Formation in the Ordos Basin and Its Petroleum Geological Significance
In order to quantify and define the features of the bottom concave and convex structure of the Yanchang Formation in several key sedimentary periods,four stratigraphic units,namely Chang 10～Chang 8,Chang 7,Chang 6～Chang 4+5 and Chang 3～Chang 1,were divided by basin simulation technology based on a large number of drilling data in Ordos Basin.The paleo structural features of the bottom of the lake basin in the Yanchang period at the end of the sedimentary period of each stratigraphic unit were quantitatively investigated.The results show that at the end of the sedimentary period of Chang 8,the structural elevation of the bottom surface of the formation is"high in the east and low in the west,high in the south and low in the north",and the structural contour of the main lake basin is below-600 m.At the end of the sedimentary period of Chang 7 Formation,the paleo geomorphology was"high in the south and low in the north".The main lake basin is mainly distributed in the north of the basin,and the structural elevation is below-1 150 m.At the end of the sedimentary period of Chang 4+5,the depression area is distributed in the northwest area of the basin,and the difference between the distribution range and the structural elevation becomes smaller,about 200 m.At the end of Chang 1 Deposition,the overall structural pattern of the bottom of the basin shows a paleogeomorphic feature of"high in the east and low in the west",and the elevation difference of the concave-convex structure of the bottom of the basin is 300～400 m.The structural features of gentle slope on the bottom of each sedimentation period are favorable areas for reservoir distribution.
concave-convex paleostructure on the ground floormain lake basin migrationreservoir distributionOrdos Basin
万方数据
维普
