(355f) Asphaltene Aggregation and Deposition in Porous Micromodel

Authors: 
Lin, Y. J., Rice University
Biswal, S. L., Rice University
He, P., Rice University
Tavakkoli, M., Rice University
Ji, S. Y., Rice University
Chai, J., University of Huddersfield
Goharzadeh, A., The Petroleum Institute
Vargas, F., Rice University
Fatt, Y. Y., The Petroleum Institute

Asphaltene deposition is a common cause of flow assurance problems in wellbores and production equipment as well as near-wellbore regions in oil reservoirs. Therefore, understanding the mechanism by which asphaltenes deposit onto solid surfaces is highly desirable. Here we present our results for visualizing real time asphaltene deposition from model oil w/ and w/o commercial waxes (C18, C32) as well as dispersants (inhibitor X and Y from the Middle East, 4-hexyl-, 4-octyl-, and 4-dodecylphenol) using microfluidic devices. In particular, we consider porous-media micromodel designs to represent various flow conditions typical of that found in the near well-bore regions of oil flow processes. Deposition rate and patterns with micron-sized circular posts for 0.5 wt% model oil will be discussed with the properties of aggregates, including the radius of gyration and fractal dimensions. Also, four stages of deposition have been found and investigated in the pore scale and with qualitatively macroscopic total collector efficiency. A permeability reduction model is also proposed for this system. By understanding the nature and the mechanisms of asphaltene deposition, we increase our ability to design cost effective mitigation strategies that includes the development of a new generation of asphaltene deposition inhibitors and improved methods for prevention and treatment of this problem.