Abstract: Well selection standards for CO2 huff and puff in Etongxin block in Shengli oilfield are determined based on prediction of minimum irascibility pressure of crude oil and CQ2, adaptability study and the preliminary field experiment results. Injection rate is calculated by using gas state equation and laboratory experiment results; operation parameters are optimized; and economic evaluation is performed on technological effects. Eighteen operations have been carried out in 16 wells achieving a success rate of 82. 8%, a cumulative incremental oil production of 20,972 tons and an input - output ratio of 1 -6. 01. This technology can enhance oil recovery of small fault block reservoirs to some extent