Abstract: The SEC standard revised in 2010 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 system, to determine the biggest oil/gas supply radius with well testing, to forecast a sand thickness with seismic technology and to interpret pay intervals with logging. Meanwhile, the basic requests for various techniques applied to the marketing reserves estimation and the number of successful cases provided compulsorily were summarized in order to meet the prerequisites of "reliable techniques", such as "consistency", "repeatability", "evidence with statistic significance" and "increasable future reserves". Therefore, an intensive understanding on relevant requirements of the SEC standard for reliable techniques is of great directive significance in the marketing reserves estimation of various domestic petroleum companies.