Abstract: Aimed at the benefits decline and production shortfall of the heavy oil reservoirs, the research of the gas injection methods for heavy oil reservoirs is conducted. From the analysis of the viscosity-temperature and rheological characteristics of heavy oil, the oil displacement mechanism and problems by steam drive process for heavy oil reservoirs are investigated. According to the theoretical analysis and the experimental results, the feasibility on exploitation of heavy oil reservoirs by high temperature compound gas drive utilizing N2, CO2 and steam properties is studied in detail. The results indicate that the high temperature compound gas drive with N2 and CO2 is better than steam drive, showing much higher crude oil recovery.

Key words: heavy oil, non-Newtonian fluid, steam drive, N2, CO2