Study On Proper Combustion Type Of Combustion Assisted Gravity Drainage

technological advantage and potential, In-Situ Combustion(ISC) is an important thermal recovery method. The early pilot study usually got failed due to insufficient knowledge of the ISC displacement mechanism and improper project design. Recently ISC becomes highly valued along with its thorough understanding. Combustion Assisted Gravity Drainage(CAGD) is a new trend of ISC, combining with the high efficiency of ISC, high oil production rate of horizontal wells and gravity drainage.In this paper, mechanism of CAGD and three development forms are summarized. Main physical and chemical phenomena are analyzed, meanwhile chemical reactions taking place in the process are described, finally mathematical model of CAGD is established. Numerical solution of the model is carried out with the discretization method after analyzing the definite condition. Features of CAGD are considered. Gas injection scheme of a concrete block is devised after analyzing the feasibility of CAGD. It's found that gas injection with low velocity is superior in which oxygen breaking through the wellbore of horizontal well can be avoided. In traditional ISC, gas injection combining with water can effectively recover the heat stuck in the burned zone, thus improving the production effect. Impact of water injection on CAGD is analyzed by means of numerical simulation, finding that water injection can't obviously improve the recovery results. This is due to short distance displacement of the process, and the mobilized oil zone is the main mechanism of the drainage process. Dry combustion is recommended in the scheme. CAGD surmount fatal defects of ISC, having widely practical future.