Purpose and approach of the reserve estimation Since the three largest petroleum companies of China were successively listed in AMEX from the year 2000,the proved reserve owned by these companies have to be estimated annually under the SEC guidelines since the listed company will make its future development Purpose and approach of the reserve estimation Since the three largest petroleum companies of China were successfully listed in AMEX from the year 2000, the proof reserve owned by these companies have to be estimated period under the SEC guidelines since the listed company will make its future development