From Lab to Field: An Approach for Effective Scale Inhibitor Recommendations in High-CO2 Cases - Lessons from Buzios Field

Abstract This paper introduces a comprehensive methodology designed to overcome the challenges of replicating oilfield scale conditions in laboratory settings, particularly for evaluating the performance of scale inhibitors in high-CO2 scenarios, with a focus on the pre-salt region. The study involves adapting Tube Blocking Tests (TBT) to accurately simulate field conditions where CO2 concentrations exceed the capacity of cationic and anionic brines under atmospheric pressure. The core of the methodology lies in modifying the TBT equipment by replacing conventional HPLC pumps with syringe pumps for carbonated brine injection and fine-tuning pH levels to closely mimic field conditions. Simulations using Multiscale flash calculation software were employed to estimate chemical equilibrium and pH ranges within the modified setup. This approach was applied to various scenarios in the Buzios field, including squeeze, subsea, and topside applications. Three calcium-tolerant inhibitors, each tailored to a specific application, were evaluated under both conventional and modified configurations to determine their minimum inhibitor concentrations (MIC). Results demonstrated that the modified TBT equipment configuration provided high repeatability and reproducibility, essential for the reliable qualification of scale inhibitors. Importantly, pH was shown to significantly influence inhibitor performance; for example, inhibitors deemed ineffective in the conventional setup proved effective in the modified configuration, eliminating the need for alternative chemical solutions. By enabling a more accurate replication of field conditions in high-CO2 scenarios, this methodology supports better chemical product qualification and reduces costs by preventing inhibitor overdosing. This work makes a valuable contribution to the field by emphasizing the critical role of replicating water chemistry in laboratory tests for the effective selection of scale inhibitors.