Study On Flue Gas Assisted SAGD To Improve Development Efficiency Of Heavy Oil

After 10 years'scientific research, pilot project of SAGD(steam assisted gravity drainage) technique transferred from later stage of huff and puff technique achieved success in 2005, both of the two techniques mentioned above are being used for developing semi-deep and deep ultra-heavy oil in Liaohe Oilfield. Now SAGD technique is experiencing popularization stage into industrialization. There is huge top water in Guangtao Formation, Du84 Block in Liaohe Oilfield. As steam chamber rises in vertical direction during the process of SAGD, the heat of steam will soften bitumen shell under top water. Finally, top water will intrude into the steam chamber, which leads to the collapse of steam chamber and failure of SAGD. Research on methods, which can improve the condition of steam chamber and prolong the lifetime of SAGD is quite necessary for IOR in wind-down process of SAGD.Solubility of flue gas in ultra-heavy oil is researched by laboratory experiment. The results indicate that solubility of flue gas improves along with pressure, volume factor at saturation pressure improves and density of mixture decreases along with solubility of flue gas. At the range of experiment temperatures, solubility of flue gas in ultra-heavy oil and volume factor are both quite small. After soluble of flue gas, viscosity of ultra-heavy oil decreases, and viscosity reducing ratio is nearly linearly improved. According to basic parameters of ultra-heavy oil and results of swelling test, fluid phase behavior was matched, which can provide believable parameters for simulation. The simulation model of flue gas assisted SAGD was created according to the basic geological data, property data of compositions, and conventional SAGD simulation model. For conventional SAGD technique, development effectiveness of former development manner was forecasted, feasibility of steam or steam/flue gas injector alternative injection is analyzed. For flue gas assisted SAGD technique, feasibility of steam/flue gas co-injection was analysed, steam/flue gas ratio and total amount were optimized. Simulation results indicate alternative injection is useful in improving expand condition of steam chamber and prolonging lifetime of SAGD. With the popularization of SAGD, flue gas assisted SAGD has a very bright future in application.