Evaluation of synthesized polymeric additives as paraffin inhibitors for wax dissolution in the petroleum reservoir rock

Abstract

Abstract Precipitation of paraffin in petroleum reservoir rock can be a challenge to oil productivity for oil and gas industries. Paraffins exist in equilibrium with the crude oil under normal reservoir temperature and pressure. During the flow of crude oil through the petroleum formation, the proportion of lighter ends in crude oil underwent variation on account of localized pressure fluctuations. It led to reduction in solubility of heavy molecular weight hydrocarbons and they precipitate in the form of wax in the pores of reservoir rock. In this paper, wax deposition from crude oil was investigated using an experimental set up. The crude oil was characterized as medium heavy and waxy crude oil. Two paraffin inhibitors were synthesized in laboratory based on amination reaction of maleic anhydride with unsaturated amines. The monomer formed underwent free radical polymerization at 75 °C. The synthesized inhibitor was doped in crude oil to check wax dissolution through pores as compared to commercial paraffin inhibitors. In addition, the core was aged with crude oil for 15 days and alteration in its wettability was evaluated through changes in contact angle hysteresis with paraffin dissolution. It was found that synthesized paraffin inhibitors showed higher contact angle hysteresis as compared to commercial paraffin inhibitors, indicating excellent solubilisation of wax deposit in the pores of core.