Enhancing Filter Cake Sealing in Ilmenite-Based Drilling Fluids Using Perlite: Performance Across Varied Densities and Filtration Media

In the realm of drilling operations, formulating drilling fluid is substantial for efficient and successful wellbore construction. This study delves into the effectiveness of perlite as a primary filtration additive in water-based mud formulations, particularly in addressing challenges associated with varied ilmenite mud densities. Experimental investigations were conducted using samples with incremental ilmenite densities, ranging from 10 to 17.5 ppg, with and without adding perlite. Filtration tests were conducted by using filter paper, ceramic disk, and core samples. Assessment of drilling fluid properties, including rheological measurements and filtration behavior, was conducted to evaluate the mud formulation performance under different conditions. The study identified a critical density threshold exceeding 15 ppg, where significant issues such as elevated filtration volume and thick filter cakes emerged, indicating stability concerns. The addition of perlite reduced the filtration volume by up to 71% and the filter cake thickness by 52% at higher densities. While perlite did not entirely prevent formation damage, it minimized core permeability reduction by up to 70% and porosity decline by 51%. Additionally, perlite exhibited some capability in enhancing the drilling mud viscosity and rheological properties, contributing to improved cutting carrying capacity and hole-cleaning processes. Perlite proved to be an effective additive in improving the filtration and rheological properties of water-based mud, addressing the critical challenges associated with high ilmenite mud densities. Its ability to reduce formation damage and solid invasion and enhance mud performance will reflect positively on other practical drilling parameters including the rate of penetration, wellbore stability, and efficient drilling operations.