Research on Wax Formation Influencing Factors and Selection of Wax Cleaning Agents in De Block of Changqing Oilfield

Summary

Based on the understanding of the wax deposition mechanism and influencing factors in the Chang 8 reservoir of Changqing Oilfield, we evaluate and optimize the performance of wax removal and prevention agents in this study. Our research results show that the De Block generally contains higher saturated hydrocarbons, while the relative content of asphaltene and resin decreases. There is a synergistic effect between corrosion and wax deposition, with corrosion products accelerating wax deposition. All crude-oil samples from the De Block feature a microcrystalline wax content exceeding 50%, with high wax viscosity, making it difficult to effectively remove with conventional methods. Inorganic salt deposition changes the fluid flow velocity distribution, promoting the easier precipitation and adhesion of wax components in crude oil on pipe walls or equipment surfaces. Among the evaluated and screened wax removal agents, Agents 1–4 demonstrated high wax removal efficiency, meeting the requirement of SY/T6300-2009 (efficiency > 0.016 g/min), whereas wax removal agents based on corrosion inhibitors showed virtually no wax removal effect. The optimal concentration of the wax removal agent was found to be 1%, and the best formulation was a 1:3 mixture of Wax Removal Agent 1 and Wax Removal Agent 2.