Control Value of Corrosion Rate for Tubing and Casing of Injection-production Well in CO₂ Flooding Oilfield

Corrosion control is the key technology of CO2 drive,the measure of adding some corrosion inhibitor into the tubing and casing of ordinary carbon steels (J-55,N-80,etc.) was used to control CO2 corrosion in tubing and casing for CO2 drive oilfield.0.076 mm/a is taken as the control value of corrosion rate in China according to the standard named as “Recommended Index and Analysis Method of Water Quality Injected in Clastic Rock Reservoirs”.And there is no unified standard abroad.From the point of view about test environment,corrosion source and corrosion environment,using 0.076 mm/a as the control value of corrosion rate for material selection is unreasonable.Under the most dangerous conditions,the average corrosion rate allowed during life cycle calculated by the strength of tubing and casing is reasonable for material selection.There is no need to set an average standard corrosion rate for corrosive environment in CO2 drive oil field as measurement index for optimization and evaluation of corrosion inhibitors.