THE INVERSION STRUCTURE ZONE AND RESERVOIR HISTORY OF THE JX1-1 AREA IN LIAODONGWAN DEPRESSION,OFFSHORE BOHAI BAY BASIN

Based on a large number of high-resolution 3D reflection seismic data,combined with methods of the balanced profile simulation,Easy% Ro simulation and basin modeling the like,the deformation characteristics and source rock maturity evolution of inversion structures of the study area are quantitatively studied and discussed,and the relationship between the inversion structure activities and reservoir history is analyzed.The research results show that the JX1-1 inversion structure zone has experienced a large-scale twisting pressure inversion effect since the Cenozoic,during the deposition of 1st and 2nd member of Oligocene Dongying Formation(since 30.3 Ma~23.3 Ma),resulting in the shortening of the basin in the NW-SE direction by 2.74 km,and the amount of eroded strata of the Dongying Formation is about 780 m and 2.73% of the basin shortening rate.The maturity evolution of organic matter of the JX1-1 inversion structure zone of Liaoning sag also shows that the source rocks are the formation of inversion structures before being mature hydrocarbon generation and expulsion,and the main source rock reaches the hydrocarbon generation and expulsion peak period dating back to 5.1 Ma.The basin modeling results show that inversion structure effect causes two-stage filling of the JX1-1 field.The first stage of filling is from 31 Ma to 24.6 Ma ago,and the second stage of filling is 9.2 Ma ago.