Experimental Study on EOR Performance of Natural Gas Injection in Tight Oil Reservoirs

Gas injection is an effective enhanced oil recovery method in tight oil reservoirs. In the case of tight oil fields with sufficient natural gas supply, natural gas injection can significantly reduce the cost of operation, leading economic benefit. Natural gas flooding might be a promising EOR method for tight oil development. Based on the material and reservoir condition of a tight formation in Changqing Oilfield, this study conducted a series of natural gas injection experiments to evaluate the feasibility of natural gas injection after water flooding and analysed the influence of gas injection rate to EOR performance. Experiment results shows that natural gas injection can recover 20.8% more oil after water flooding. Sensitivity analyses indicates that natural gas injection had a higher oil recovery with low injection rate.