Numerical simulation of paraffin wax deposition in waxy crude oil reservoir with cold water flooding

The waxy crude oil translates single-phase liquid into two-phase solid-liquid due to paraffin wax deposition, as the temperature of injection water is below wax appearance temperature. The precipitating paraffin wax in the pores affects oil production due to reduction of porosity and permeability. In this paper, a numerical simulation model was established by establishing porous physical model with irreducible water and waxy crude oil under original reservoir condition, introducing a phase transformation equation and combining the mathematical model of a two-phase oil-water seepage field. Several typical characteristics of cooling damage were obtained. The worst cooling damage is not at the injection well wall, but it gradually moves to deep reservoir as injection time increases, while the damage degree gradually increases. The damage degree of injection well wall does not increase with increase in injection time, but remains constant. The magnitude and scope of the cooling damage gradually increases and its fluctuation characteristics clearly increases.