Palaeogeomorphology restoration of Majiagou formation in southern Baota area of Yan'an gas field and its geological significance for oil and gas exploration
Karst paleogeomorphology is one of the factors affecting the distribution and development of karst reservoirs in weathering crust.Restoring karst paleogeomorphology is very important for guiding oil and gas explora-tion.Based on logging,mud logging and core data,the mesomorphic stratigraphic framework of the Majiagou Formation in the south of Baota in Yan'an gas field is established,and the mesomorphic stratigraphic interface at the top of Benxi formation and the top of Mawu 5 are used as the datum plane to restore the characteristics of the top of Lower Paleozoic,and the reconstruction of the top surface of Majiagou Formation in the study area is carried out.The results show that the study area can be divided into three secondary geomorphic units,highland,slope and basin and secondary geomorphic units,such as highland,platform terrace mound,erosion gully,basin and trench.The top surface of the Majiagou formation in the study area is of high in the middle,low in the east and west,high in the south,and low in the north.The central and southern Yuanlongsi-Yaodian-Nanniwan areas are karst highlands,the southwestern Ansai-Zaoyuan and the eastern Liangjiahe-Liujiahe areas are karst slopes,and the Guanzhuang,Linzhen,and Louping areas are karst basins.According to the relationship between paleogeomorphic units and reservoir development,the erosion gully unit in the karst slope is conducive to the formation of reservoirs and is a relatively favorable area for natural gas exploration.This research can enrich the theory of oil and gas ac-cumulation and is of great significance to the subsequent development of karst reservoirs.
Yan'an gas fieldMajiagou formationpaleogeomorphology restorationkarst reservoirgelogical significance
NETL
NSTL
万方数据
