Experimental Investigation and Deposition Model of Barium Sulfate Scale Deposition in Pipelines

Abstract

Abstract Seawater injection, a widely adopted secondary recovery technique in offshore oilfields for enhancing oil recovery, introduces a significant challenge during production – the emergence of barium sulfate scaling issues in pipelines. This issue arises due to the ionic incompatibility between barium-rich formation water and sulfate-rich seawater. Acknowledging the paramount importance of comprehending barium sulfate scale deposition kinetics, this study undertakes dynamic flow experiments to craft a novel deposition kinetics model for the accurate prediction of barium sulfate deposition in pipelines. Using a dynamic flow apparatus, comprehensive investigations were conducted into scale deposition within pipelines under varying temperatures and concentrations, which involved the co-injection of formation brines into reaction tubing. After the injection, an analysis of pipeline dissection was performed to examine the barium sulfate deposition profile along the pipeline. Addressing the intricacies of ion advection, diffusion, reaction, and alterations in pipe geometries simultaneously, a holistic approach was achieved by solving fully coupled fluid flow and reactive solute transport equations. The evolution of reactions on the pipeline's surface was computed using the level set method. The precipitation process of the pipeline was simulated across diverse flow field and response reaction kinetics, culminating in the determination of the reaction rate (K) based on changes in the pipeline's geometric shape. In instances of slow kinetics (Damköhler number <1), nucleation and crystal growth exhibited a more uniform distribution from the pipeline wall. Conversely, for faster kinetics (Damköhler number >1), deposition rates peaked at the pipeline inlet. In such cases, deposition predominantly occurred near the entrance, resulting in a rapid pressure loss.