The Technique of CO2 Anticorrosive in Daqing's Deep Gas Well

Abstract

Abstract The oil tubes and casings' corrosion had been researched under high pressure, high temperature in the Daqing's deep gas well regions. This paper analyzed CO2 corrosion environment's feature and principle in the lab and on the deep gas well field to grasp the CO2 corrosion rules and develop optimizing evaluation for the various casing pipes and corrosion inhibitors in the deep gas well, had been finished optimizing the completion pipe string design and technique to be most reasonable economical. These techniques supported the anticorrosive scheme design for various CO2 deep gas wells, established the reasonable productivity and provided the integrated various economic rational CO2 anticorrosive technologies for the development of the Daqing's deep gas well regions. All the drilled gas well which had the industrial natural gas in the Daqing's deep gas well regions were high temperature, high pressure characteristics, there were 41.3% gas well was serious corrosion which the CO2 partial pressure was more than 0.2MPa. At the beginning of exploratory development, mostly materials of gas wells' oil tubes and casing pipes were made of the common carbon steel, the CO2 corrosion was very serious on these oil tubes and casing pipes. Although the exploitation oil tubes and casing pipes were made of 13Cr alloy steels can obtain the better anticorrosive effect but the cost of these tubes and casing' price was very high which cost was 5 ~ 6 times to the ordinary carbon steel casing pipes. Use lower investment price with the anticorrosive infection to invent and create a corrosion inhibitor control technique of economic rationality and auxiliary project.