RESERVOIR FORMING CHARACTERISTICS AND GEOLOGIC RISK EVALUATION OF THE BURIED HILL TRAPS IN THE JIYANG DEPRESSION OF THE BOHAIWAN BASIN

There are mainly three types of the buried hill traps in the Jiyang Depression of the Bohai wan Basin.They are fault block,hammock and internal types of buried hill trap with different reservoir forming chacteristics.Different geologic conditions play a different role on the buried hill trap reservoir forming.When five evaluation conditions and weight coefficient of each gelogical element were researched,the difference and the actual features of Jiyang depression should be fully reflected.Hierarchical evaluation criteria may be established by applying the methods of drilling success ratio hierarchy,cumulative probability curve and geologic analysis for the geological elements of the trap.The application presents that the established evaluation methods and criteria for the geologic risk in a buried hill trap can reflect the geological characteristics and actual exploration situation of the exploration area.