Quantitative Characterization of Heavy Oil Threshold Pressure Gradient in Porous Media

Abstract A large number of laboratory physical experiments and oilfield production practices show that the flow of heavy oil in porous media no longer follows Darcy's law, but needs to overcome a certain threshold pressure gradient (TPG), which determines the difficulty of heavy oil flow, directly affects the development effect of heavy oil reservoirs, and has important engineering significance. However, the current quantitative characterization methods of TPG of heavy oil have limitations. In this paper, the TPG of heavy oil is measured through experiments, and its influencing factors are comprehensively analyzed. Finally, a new quantitative characterization is proposed. The results show that when the viscosity and permeability are the same, the TPG of heavy oil is not necessarily the same; The TPG of heavy oil increases with the increase of asphaltene content or resin content, and decreases with the increase of aromatics content, saturates content, permeability or temperature. The TPG of heavy oil can be scientifically characterized by the above factors, and ordered according to influence from high to low: temperature, permeability, asphaltene content, saturates content, aromatics content, and resin content. The accurate characterization of the TPG of heavy oil has great significance for the development evaluation, remaining oil characterization and enhanced oil recovery of heavy oil reservoirs.