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A Promising Flow Assurance Application of Superparamagnetic Nanoparticle Heating for Wax Removal in Offshore Pipeline and Production Tubing: Mechanism and Simulation


 Wax deposition is an intractable flow assurance challenge for the petroleum industry. For wax remediation, varieties of approaches have been proposed and mechanical pigging ranks among the most widely used ones. To lower the risk of pig stalling and improve the cleaning efficacy in pigging, this work uses superparamagnetic nanoparticle (SPM-NP) heating to soften the wax layer. It involves installing a magnetic field induction coil on conventional pig and coating a nanopaint on the inner wall of the pipe. The SPM-NP pigging system is actually a combination of mechanical pigging and thermal management. The yield stress of the prepared wax samples was experimentally determined to be binomially correlated to temperature. The COMSOL software was used to simulate the temperature field. A methodology to estimate the wax resistive force in pigging was proposed. It was found that the SPM-NP pigging system decreases wax resistive force by up to 20–40% in the given cases, which effectively lowers the risk of pig stalling accident. Multiple factors affecting wax resistive force were also investigated. Compared with wax melting formula, the softening approach dramatically slashes the required current intensity to a realizable level for field pigging operations. It could be a promising alternative for conventional pigging in wax remediation and hydrate prevention for offshore pipelines and production tubings.