Perlite-modified micromax-based drilling fluids: improved filtration control and rheological performance

Abstract In high-density water-based drilling fluids, optimizing filtration behavior, filter cake characteristics, and rheological properties is essential for efficient and safe drilling operations. This study investigates the impact of perlite addition on these critical properties using three mud formulations with varying densities. Filtration tests were conducted using filter paper and ceramic disks, while rheological properties were evaluated using industry-standard models. Results revealed that increasing mud density leads to higher filtration volumes and thicker filter cakes, which potentially compromises wellbore stability and increasing the risk of pipe sticking. However, the incorporation of perlite significantly enhanced performance by reducing both filtration volume and filter cake thickness across all densities. Rheological models’ assessments illustrated that the perlite had minimal impact on plastic viscosity (PV) and yield point (YP), but a notable improvement in gel strength behavior, indicating better management of cuttings and entrapped air in drilling operations. Among the tested rheological models, the Herschel-Bulkley models offered the closest fluid behavior to the experimental data without and with the perlite addition. These findings highlight perlite’s potential as a valuable additive for enhancing water-based drilling fluids, enhancing operational efficiency and minimizing drilling complications. This study demonstrates perlite effectiveness as a primary additive in Micromax-weighted fluids, extending the operational density range and offering a practical, low-cost solution for HPHT conditions.