(125a) Probing Asphaltene Deposition Using Microfluidic Devices

Asphaltene deposition is a common cause of significant flow assurance problems in wellbores and production equipment as well as near-wellbore regions in oil reservoirs. Therefore, a better understanding of the mechanism by which asphaltenes deposit onto solid surfaces is highly desirable. Here we proposed a novel methodology for probing asphaltene deposition using microfluidic devices that model porous media. A variety of factors influencing asphaltene deposition will be investigated, including fluid flow pattern, asphaltene polydispersity, and solvent effects. Real time visualization of asphaltene deposition in microfluidic channels is realized. First, this micromodel is well characterized with known properties of flow in the oilfield. Second, the model system of pure C5+ asphaltenes in toluene with a known asphaltene instantaneous onset concentration is used to eliminate the disturbance from unknown components in crude oil. Coupled with the indirect method and images of aggregates, precipitation and aggregation effects are discussed with deposition rate by varying the injection ratio of n-heptane in the porous media both in the pore scale (visualization) and macroscopically qualitatively (collector efficiency). 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.