Microfluidics – A New Tool to Differentiate Chemistry for Fracs – Functional Frac Performance Vs Reservoir Performance

Abstract Unconventional reservoirs play an important role in the global energy supply nowadays due to recent advancements in hydraulic fracturing. It has been reported that the selection of completion chemicals has a significant impact on oil and gas production due to fluid incompatibility and polymer-induced formation damage. To optimize oil and gas production, flowback efficiency, and fracturing fluid-induced permeability damage, different completion fluid packages were evaluated using microfluidics. Two microfluidics chips were designed to evaluate regain conductivity and flowback efficiency in this work. The regain conductivity chips, representing proppant-packed fractured zones, were designed with two different fracture depths. The flowback chips consist of a high permeability zone and nanoscale channels to simulate fluid characteristics and transport in fractures, matrix, and their interface. Time-lapse microscopic images and videos of the chips were recorded during testing and the oil production was quantified using an automated images analysis platform. Microfluidic experiments were conducted using filtered produced water and oil samples collected from the field. In microfluidics experiments, friction reducers with similar flow loop performance, or functional frac performance were chosen and compared on the regain conductivity and flowback tests. The results of the regain conductivity tests showed that the regain conductivity of the best performing group was 25% higher than the worst performing group. The flowback tests demonstrated significantly higher oil production rates and total oil flowback volume, about 50%, in the best performing group compared to the worst one. This study introduces novel selection criteria for the design of completion fluid packages, aiming to optimize oil production in unconventional reservoirs. The pore-scale optical access of microfluidics enables a better understanding of formation damage and oil recovery mechanisms. Additionally, this microfluidic approach offers significant reductions in testing cost and time while providing improved reproducibility compared to traditional testing methods.