The SEC standard revised in2010 definitely puts forward a new mode to estimate the newly discovered reserves by utilizing reliable techniques instead of the traditional mode that is based on the well-control extent and testing result.Based on the PetroChina's estimation practice for more than ten years,four types of reliable techniques frequently used by domestic oil companies to broaden the estimation scope of the proved reserves were summarized,i.e.to determine a hydrocarbon-water contact with pressure sy...