Experimental Study On In-situ Combustion Of Brazilian Heavy Oil

The present work refers to an experimental study on oil recovery by in-situ combustion. A specific apparatus holding a combustion tube of 100 cm in length and 6.9 cm internal diameter was designed and constructed for the study. Experimental tests were performed with a heavy oil of 12.8°API from a Brazilian onshore field. Plain air was injected at a constant rate of 3 SLPM, while the production pressure was set at 10 bar. The main purpose of this study was to survey the influence of clay content in the reservoir rock with initial oil saturations ranging from 25 to 50%. The results indicate that the in-situ combustion method is technically applicable to the rock-fluid system tested. Moreover, the tests were useful in providing the proper range of parameters for the oxidation reactions to occur. Clay has proved to play a key role on fuel deposition and, consequently, on propagation of the combustion front. In a clean sandpack medium, the combustion front was not self-sustained, while in presence of clay, in amount ranging from 4.5 to 10.0% mass fraction, sustainable combustion reactions were achieved. Front peak temperatures were recorded in the range of 457-501 °C, and for oil recovery factors were greater than 84%. From the set of data collected during the tests, results show combustion front velocities to span between 14.1 to 18.3 cm/h. Worth mentioning, upgradings of 3.2° to 8.4° API were observed in the produced oil. The basic combustion parameters - fuel consumption, air requirement, air-fuel ratio, atomic H/C ratio, oxygen utilization - obtained during the experiments are favorable to the implementation of in-situ combustion and shall be used as a guide to the pilot project planned for the field. Copyright 2009, Society of Petroleum Engineers.2674684Bagci, S., Estimation of Combustion Zone Thickness during In Situ Combustion Processes (1998) Energy & Fuels, 12, pp. 1153-1160Castanier, L.M., Baena, C.J., Holt, R.J., Brigham, W.E., Tavares, C., In Situ Combustion with Metallic Additives, SPE 23708, 1992Farouq Ali, S.M., Heavy Oil - evermore mobile (2002) Journal of Petroleum Science & EngineeringGreaves, M., Xia, T.X., Turta, A.T., Ayasse, C., (2000) Recent Laboratory Results of THAI and Its Comparison with Other IOR Processes, , SPE 59334Greaves, M., Young, T.J., El-Usta, S., Rathbone, R.R., Ren, S.R., Xia, T.X., Air Injection into Light and Medium Oil Reservoirs: Combustion Tube Studies on West of Shetlands Clair Oil and Light Australian Oil (2000) Trans IChemE, 78 (PART A)He, B., Chen, Q., Castanier, L.M., Kovscek, A.R., (2005) Improved In-Situ Combustion Performance With Metallic Additives, , SPE 93901Mamora, D.D., (1993) Kinetics of in situ combustion, , Stanford UniversityMoore, R.G., Laureshen, C.J., Belgrave, J.D.M, Ursenbach, M.G., Mehta, S.A., In-Situ Combustion: New Ideas for an Old Process, Presented at the 11 th Annual Canadian Heavy Oil and Oil Sands Symposium. Calgary, Alberta, Canada, 1994Pereira, A.N., Estudo termoanalitico e cinetico das reações de oxi-combustão de óleo pesado, (2008), Master dissertation, Faculdade de Engenharia Mecanica, UnicampRamirez-Garnica, M.A., Mamora, D.D., Nares, H.R., Schacht-Hernandez, P., Mohammad, A.A., Cabrera-Reyes, M.C., (2007) Increase Heavy-Oil Production in Combustion Tube Experiments Through the Use of Catalyst, , SPE 107946Rodriguez, J.R., Experimental and Analytical Study to Model Temperature Profiles and Stoichiometry in Oxigen-Enriched In-Situ Combustion, (2004), Ph.D. dissertation, Texas A&M UniversitySarathi, P.S., (1999) In-Situ Combustion Handbook - Principles and Practices, , BDM Petroleum Technologies, OklahomaXia, T.X., Greaves, M., (2001) Downhole Upgrading Athabasca Tar Sand Bitumen Using THAI - SARA Analysis, , SPE 6969