Engenharia

Combustão In Situ: Experimentos e Simulações Numéricas
Ribeiro G. B. Jr., Unicamp; Trevisan O. V., Unicamp

Abstract As the world reserves of light oil steadily decreases, heavy oil and tar sands resources may turn into the future source of energy. In situ combustion (ISC) is a promising recovery technique for this type of hydrocarbon, otherwise difficult to produce. Combustion tube laboratory experiments and numerical simulations are essential for the design of field projects. This paper reports both aspects of an ISC study carried out with a 12.8 ºAPI crude from a field candidate to a pilot project in Brazil. The experimental tests were performed in a combustion tube of 100 cm in length and 6.9 cm internal diameter filled with sand graded at 60-80 mesh. Plain air injection was injected at a rate of 3 SLPM and the production pressure was set at 10 bar. Results from the tests show that clay plays a key role on fuel deposition. Also, important combustion parameters like fuel consumption, air requirement, air-fuel ratio, atomic H/C ratio, oxygen utilization were obtained. Values are favorable to the implementation of the in-situ combustion pilot project planned for the field. The numerical study was developed using a commercial simulator. The aim was to analyze the process in the lab scale, the physical model corresponding to the combustion tube used. The fluid model was adjusted by a commercial software to a total of 7 components; heavy oil, light oil, CO2, O2, N2, H2O and coke. The combustion process considers 4 oxidation reactions. The numerical results were history matched to the data derived from the experiment. The important findings in this part o the study were the influences of each variable on the overall ISC process. Besides, it was concluded that the fluid model and the reaction model are key in the history matching task.

Resumo Como as reservas mundiais de óleo leve estão decrescendo continuamente, campos de óleos pesados podem se tornar uma fonte