Using The Gravity And Magnetic Data To Study The Pre-cenozoic Basin Structure In The Bohai Sea

Oil is an important resource.The lack of oil will restrict the development of economy and menace the safe of national defense badly.Therefore,it is significative to find new frontiers of oil exploration to increase oil and gas reserves.The Pre-Cenozoic residual basin in China Sea area worthy of studying is one of the new frontiers of oil exploration.The Bohai sea,as a part of China continental shelf sea,has been explored from 1950s.It is successful to drill the first hole named H1 in 1966,which got 35.2t oil per day from the Minghuazhen Group of Pliocene.The exploration of the Bohai sea got great achievement and contributed to the development of economy.But the research of the Bohai sea does not finish.Now,the main targets in the Bohai sea area are almost focusing on tertiary stratum,and there is few research in the Pre-Cenozoic stratum.Because the Pre-Cenozoic residual basin is deep,long historic and reconstructed intensively by later tectonic movement,it is expensive and difficult to explore.It is one of the effective methods to research the Bohai sea by carring out the study of synthetical geology and geophysics.This thesis take the Pre-Cenozoic residual stratum as the reserch object and "The region restricts the local and the deep restricts the shallow" as the guiding ideology,and synthesized the data of shipborne gravity,aeromagnetic and typical seismic section,especially the data of high precision airborne gravity.This thesis used the method of Parker to calculate the depth of magnetic and gravity basement and plotted out the distribution of the Pre-Cenozoic residual stratum,based on the collection,statistic and analysis of petrophysics.This thesis abstracted the fracture of basement and the distribution of magmatic rock by field data processing and provided reference for the Pre-Cenozoic oil exploration.This thesis selected two sections across the Huanghekou depression,and used the magnetic and gravity interpretation system to calculate sections.The result of the sections accorded with that of the plane.Based on the research upward,this thesis plotted out the perspective area of the Pre-Cenozoic.