重質油の原位置燃焼に関わる燃焼反応モデルの修正による数値シミュレーションの安定化

抄録

In-Situ Combustion (ISC) is the oldest thermal oil recovery method, however, only four projects have been carried out in the world, because controls of combustion front and oil production are extremely difficult compared with steam injection. Recently, the toe to heel air injection (THAI) method is expected to have several advantages on combustion control, oil recovery ratio, costs of production and water treatment compared with steam injection methods, such as SAGD method using horizontal wells. THAI method also uses a horizontal producer that controls the combustion front and downward gravity oil flow to the producer. To promote THAI method, the reliable kinetic chemical model on ISC process has been required for field scale simulations.

Chen et al. (2014) carried the history matching using the kinetic model for the combustion tube tests. However they didn't show good matching with the measurement results, since their model was not proper to simulate chemical reactions of Coke generation from Asphaltenes. In this study, the classification of four oil components, Saturates, Aromatics, Resins and Asphaltenes (SARA), were applied to construct ISC modeling. A new pseudo component called as “Partial Oxygenated Asphaltenes (POA)” has been proposed based on measurement results of a thermal gravity analysis (TGA) and the batch reactor test by revising the Chen et al.'s model. The present model using 11 chemical reactions including POA has been confirmed to show a reasonable matching with the TGA result that POA mass increased in air with O₂ absorption under 200°C and decreased above 200°C with thermal cracking of Asphaltenes. To reduce computational time, 5 chemical reactions were screened from original 11 reactions. In addition, the model of 5 reactions was successfully applied to the field scale simulation by THAI method with reducing frequency factors in the kinetic reactions to eliminate the influence of grid-block size.