Understanding and Optimizing the Impedance-Based Microfluidic “Tube Blocking Test” for Boosting the Testing Capacity of Scale Inhibitors

Inorganic salt deposition has a significant impact on industrial workflows, ranging from reducing heat exchanger efficiency to causing pipeline clogging on offshore oil platforms. To mitigate the damage caused by scaling, the most common approach is the use of scale inhibitors, whose efficiency is assessed through tests in a procedure known as the tube blocking test (TBT). Although it is a well-implemented technique, the TBT method requires benchtop equipment, limiting its use on offshore platforms. To overcome this challenge and improve sensitivity, electrochemical sensors are emerging as a promising solution for scaling detection. Furthermore, some oilfield scaling conditions, when replicated in the laboratory environment, take a long time to develop─such as in brines with low scaling potential─significantly increasing the scaling time (ts). In this context, this work aims at the comprehensive investigation and validation of an impedance-based device (TBTimp), in addition to its optimization, evaluating the effects caused by changes in its fluid dynamics, as well as increasing the throughput of antiscaling products, based on the reduction of ts. The device was challenged under different temperatures (61 to 130 °C), pressure (285 to 1000 psi), and salinity conditions, and validated in conventional TBT equipment, demonstrating its versatility and applicability. Furthermore, the scaling kinetics were investigated through the impedance measurements, enabling an understanding of the operating principles and the time-function relationship between scale formation and Z of the TBTimp. For the optimization stage, modifications were made to the mixing capillary (counter electrode, CE), PEEK connection, and test capillary (working electrode, WE) to optimize ts. A reduction of up to 79% in ts was achieved, maintaining the method’s effectiveness in determining the minimum inhibitory concentration (MIC) of the evaluated product.