In situ probing of wax precipitation of waxy oil using oblique-incidence reflectivity difference at open bulk surface

Abstract

Considering the negative effects of wax precipitation during petroleum transportation on flow assurance and profit loss, in this study, oblique-incidence reflectivity difference (OIRD) analysis is demonstrated to be a powerful tool for the in situ analysis of wax precipitation. Based on the hybrid detection of waxy oil and natural cooling, we develop a detailed wax precipitation model for waxy oil and demonstrate that it can be used to predict actual precipitation features, which are amenable to experimental validation. The curve trend of the OIRD detection exactly reveals the wax formation process, including nucleation, growth, and crystallization. The efficiency of this technique is proven by the fact that the OIRD signals provide the detailed characteristics of the wax precipitation, which include not only the wax appearance temperature (WAT) but also the rate of change of the crystallization process. The advantage of distinguishing between the different stages of the complex wax crystallization process with time and amplitude is demonstrated.