Research On Infiltrating Mechanism Of The Steam-Assisted Gravity Drainage

Steam-Assisted Gravity Drainage has increasingly come under people's attention as an advanced technology of producing extra-heavy oils. It's very important to study the steam assisted gravity drainage (SAGD)technology which is a very effective method in developing heavy crude oil reservoirs, especially extra heavy oil reservoirs.This article studies the SAGD technology in two ways .One is the theoretical research and the other is numerical simulation. Theoretical researches begin with the basic theory of SAGD, illustrate the oil displacement power, well spacing pattern, exploit characteristic. Then found the mathematical model for dual horizontal wells SAGD on the basis of Butler theory, and get the analytical solution, also study how does the viscosity-temperature characteristic of oil,and velocity of steam-oil interface influence the oil production rate. At the same time , found the mathematical model of vertical-horizontal wells SAGD and verify the validity of the model by comparison with the actual production data.In the other way , taking an example of dual horizontal wells, the numerical models are created to study the behavior of the oil saturation, pressure and temperature in the process of SAGD, then analyze the develop-process of steam chamber and flow method of the liquid. And then study the exploit effects under different geological parameters, such as net pay thickness,porosity and oil saturation and so on; then obtain the result how the geological parameters affect SAGD progress. And then study the 4th period in the process of SAGD which is divided into four periods. Optimize the location of wells and injection-production parameters. At last,numerical prediction results are contrasted to theoretical calculation results and actual production data, the results indicate that they get good matched, which verify the validity and credibility of the analytical results.and the feasibility of SAGD applying to exploit extra heavy oil reservoirs.This paper study the infiltrating fluid mechanism of SAGD through both the mathematical approach and the numerical simulation,and lays the theoretical foundation for oil displacement theory and practical application in SAGD.