An experimental study on CO2 injection in buried hill reservoirs was conducted.A 35 MPa,CC level wellhead,Y441 high-temperature and high-pressure gas sealing packer,and BGT3 type airtight buckle oil pipe were selected for high-temperature and deep liquid CO2 injection.The mechanism of CO2 corrosion was clarified through indoor experiments,and the upper casing was protected by employing a packer to seal and replacing the annulus with protective fluid.The formulation of the corrosion inhibitor for the annulus protection fluid is designed as HZ-4.The reliability of the gas injection pipe string was verified through experiments.The cumulative injection of 13 000 tons of liquid CO2 corresponds to the oil increase of more than 800 t in the oil well stage,which shows that the buried hill reservoir of Wumishan has good injectivity and the conditions for large-scale CO2 storage.It also proves the feasibility of CO2 flooding to improve oil recovery,which is of great significance for the buried hill reservoir to carry out large-scale carbon storage and carbon flooding and help China achieve carbon peaking and carbon neutrality.
关键词
碳埋存/碳驱油/注气管柱/套管防腐
Key words
carbon storage/carbon flooding/gas injection pipe string/corrosion protection of casing
万方数据