Asphaltene precipitation onsets for light and heavy oils in Argentina

PADRO JUAN MANUEL; SMAL, CLARA; CISMONDI, MARTIN

New York

Conferencia; PetroPhase2020 (Virtual) The 21st International Conference on Petroleum Phase Behavior and Fouling; 2021

PetroPhase

Asphaltenes constitute the most polar and heavy fraction of crude oils, being insoluble in alkanes like n-Heptane, but soluble in Toluene or other aromatics. Their precipitation from reservoir fluids often creates problems of different type in the oil & gas industry, including formation damage with reduction of conductivity in the reservoir, flow assurance problems in tubing and surface facilities or flow lines, and even fouling in refineries, due to blending of crudes of different type, which can also cause asphaltene destabilization. In order to be able to take the right decisions regarding prevention and mitigation of these problems, it is important to know not only the asphaltene content but also -and more important- their tendency to precipitate. This can be mainly expressed through onsets, which are saturation points where precipitation starts, due to changes in pressure, temperature or composition [1].This work presents preliminary results for the determination of asphaltene precipitation onsets for different dead oils from Argentina, by dilution in n-pentane or n-heptane. The experimental work was based on the ?indirect method? as described in recent publications [2,3]. This method, which is a combination of gravimetric and spectroscopy techniques, is proposed for obtaining the detection of asphaltene precipitation along the dilution process. Detection of the onset for asphaltene precipitation depends on the aging time of the samples, kind of oil, precipitating agent and temperature. Time-dependency is related to the minimum particle size separated by the centrifugation process. The adaptation of the default recommendations to light or heavy oils are discussed, as well as options for pre-processing of oils with different contents of emulsified water. To our knowledge, this is the first time that this type of methodology has been applied to Argentinian oils. References[1] F. M. Vargas, M. Tavakkoli, ASPHALTENE DEPOSITION: Fundamentals, Prediction, Prevention, and Remediation, CRC Press, 2018.[2] M. Tavakkoli, M. R. Grimes, X. Liu, C. K. Garcia, S. C. Correa, Q. J. Cox, F. M. Vargas, Energy Fuels, 29 (2015), 2890-2900.[3] M. Tavakkoli, A. Chen, C. Sung, K. M. Kidder, J. Jin Lee, S. M. Alhassan, F. M. Vargas, Energy Fuels, 30 (2016), 3676-3686.