Simulating Paraffin Wax Deposit Removal: A Numerical Study of SGN Application

Offshore oil exploration encounters numerous challenges, the formation of paraffin wax deposits ranks among them. The Nitrogen Generating System (SGN) emerges as a hybrid technique, utilizing a thermochemical reaction with nitrogen salts to generate heat and facilitate the melting of paraffin wax deposit. Given the substantial heat release during this reaction, a meticulous approach is imperative to prevent potential damage to the oil pipeline. This study focuses on the numerical simulation of an SGN application, addressing the heat conduction problem, by solving a transient two-dimensional heat conduction model with phase change and chemical reaction. Approximately 70% of paraffin deposit was removed after 3 hours of SGN application. After 5 hours of SGN simulation, with a pH level of 4 and initial concentration of 2 mol/l, a liquid fraction of paraffin wax of 0.9 was observed. This result is consistent with other studies, such as thermal washing and active electrical heating techniques. The dynamic behavior of the liquid fraction obtained in simulation also aligns with previous works, showing a nonlinear and decreasing rate of melted paraffin wax. The SGN simulation identified a phenomenon called “heat spike”, in which the chemical reactants are quickly consumed, leading to a sudden temperature increasing. This effect is significantly influenced by the pH level and initial concentration. The findings offer valuable insight into the efficacy of the SGN technique in mitigating paraffin-related issues, highlighting the importance of precise control over reaction variables for optimal results.