Heavy organic deposition (asphaltenes, waxes, hydrates, etc.) on the wall of oil pipelines is often regarded as a serious problem due to technical and economic implications. Because the asphaltene deposition causes an effective reduction of the cross section of the pipes, it is important to study the effect of this reduction on the most important hydrodynamic parameters of a well, such as pressure drops, flow regimes, and inflow performance behavior, just to mention a few. To address the role of reductions to the flow of hydrocarbons in vertical pipe systems, we present a compositional flow model that accounts for reductions to the flow of a produced hydrocarbon mixture. In this work, we study producing wells ("A" and "B") located in southeast of Mexico. In the case of well A, we show the results of an asphaltene deposition simulation and the total pressure drop as a function of time along the pipeline, while for well B, we show the results obtained for the total pressure drop as a function of the different artificial reductions along the well.