Multi-round CO2 Viscosity-reducing Oil Production Technology without Pulling out Downhole Pipe Column

Abstract

Carbon dioxide injection can improve the recovery rate of heavy oil and reduce the viscosity of heavy oil as well as reduce carbon emissions. However the downhole tubular material is very easy to react electrochemically with CO₂ under high temperature and humid environment after CO₂ injection, which causes strong corrosion to the downhole tubulars. For directional wells, it will further aggravate the tubular bias wear and cause a significant shortening of the pumping inspection cycle. Moreover production will decrease after a period of time CO₂ throughput and re-injection of CO₂ will be required. In this paper, we have developed a multi-round carbon injection and heavy oil production technology without moving the tubing column. Also the supporting tools match the technology is optimized and improved to achieve the goal of extending the operation cycle and saving cost.