Abstract: At present,there are 119 drilled wells in north block of Baolang oilfield,with basically imperfect well pattern and greatly improved well control degree.As the understandings on geological structure and reservoir characteristics have been deepened,bigger changes have been taken place in reserves calculation and the reservoir reserves need to be reevaluated.Combined with reserves recalculation of north block of Baolang oilfield,the research on new understandings of the block reservoir characteristics,reserves parameters changes and their effects on reserves have been carried out.