Study On The Faults And Denudation In Jizhong Oil-rich Sag

After many years of exploration and development, Jizhong oil-rich sag is still rich in oil and gas resources. Based on the latest logging, drilling and seismic data, the author studied the characteristics of faults in Langgu sag, Baxian sag and Raoyang sag in terms of level and geometric combination features of faults, then studied the distribution characteristics of unconformity styles in three sags above, and then restored eroded thickness by using unconformity surfaces.Langgu sag is in the north of Jizhong oil-rich sag, and its development is controlled by Daxing fault and Hexiwu fault, two first-grade faults. In the sag there are parallel unconformity, truncated unconformity, overlapping unconformity and folded unconformity, which are controlled by faults of all grades. The distribution of erosion thickness in late Es4 is corresponding to the tectonic movement intensity at the same time. In Es3, the strongest denudation happened in Hexiwu structural belt, and in Es2, with the enhancement of Hexiwu East fault activity, denudation mainly happened in the east of the sag.Controlled by Niudong fault, there are multi-phase unconformities in Baxian sag. In Es2, debudation mainly happened in Chaheji-Gaojiabao structural belt, and the eroded thickness of this area was as much as 700 m. During the sedimentary period of Dongying Formation, the strongest erosion happened in Chaheji-Gaojiabao anticline structural belt, followed by Taishan structural belt and Changfengzhen-Wenan structural belt.Raoyang sag connects with Baxian sag, and there are also many kinds of unconformities in it. In Es4, the denudation of this sag mainly happened in areas such as Gaoyang-Boye structural belt, with the max eroded thickness of 700 m. In Es2, the whole sag was widely eroded, and in Renqiu structural belt and Gaoyang-Boye structural belt, the eroded thickness was as much as 1000 m. During the sedimentary period of Dongying Formation, the eroded thickness of the south was larger than that of the north, and the east larger than the west.By analyzing and summarizing, it can be concluded that the whole Jizhong depression experienced the strongest erosion in Es2 and the eroded thickness reached its maximum.