Modeling of asphaltene and other heavy organic depositions

Abstract Well-head production of petroleum can be significantly affected by flocculation, deposition, and plugging of asphaltene, paraffin/wax, and/or diamondoid inside the well. The economic implications of such a formation damage are tremendous. In this paper a comprehensive mechanism and predictive model for such compounds in oil wells is presented. This model is based on the macromolecular theory of polydisperse polymer and colloidal solutions, kinetics of aggregation, electrokinetic transport phenomena, and phase behavior of multicomponent mixtures. One question of interest in the oil industry is “when” and “how much” heavy organics will flocculate out under certain conditions. Since a petroleum crude generally consists of a mixture of light and heavy hydrocarbons and heavy organics it may be necessary to look at this problem from a more fundamental point of view than it has been the practice in the past. In this paper the author presents the cause-and-effect mechanisms of such depositions and introduces mathematical models to be used for preventive measures in various cases of petroleum production, transportation, and processing. With the application of the proposed model a number of predictive case studies are made. It is shown that with proper planning in the production scheme, consideration of the characteristics of the producing petroleum, injection fluid, well casing, and the reservoir it is possible to choose a formation-damage-free production scheme.