Exploring the Synergistic Effects of Pumice and Fly Ash on Filtrate Loss Control in High-Density Water-Based Drilling Muds for Geothermal Wells

ABSTRACT: One of the key challenges confronting the geothermal industry is the excessive filtrate loss from drilling fluids into the formation, which hinders the successful drilling of geothermal wells. Conventional filtrate loss additives often exhibit limitations that make them less desirable for long-term use. This study investigates the synergistic effects of fly ash (F) and pumice powder (P) (well-known pozzolanic materials) on the sealing properties of high-density water-based drilling mud, offering a novel alternative to traditional filtration additives. The performance of the formulated muds was evaluated across a range of temperatures (100°F - 400°F) to simulate geothermal drilling conditions. Key parameters such as filtrate loss, filter cake thickness, and rheological behavior were carefully analyzed. The results indicated that the water-based mud containing a 75%/25% combination of pumice and fly ash exhibited superior performance in reducing filtrate loss, producing thinner filter cakes, and maintaining optimal rheology. XRF analysis revealed that pumice has a higher silica content than fly ash, contributing to its enhanced siliceous properties. The study demonstrates the potential of using a binary mix of pumice and fly ash as a cost-effective and environmentally friendly alternative to conventional filtrate loss additives in geothermal drilling operations. The findings suggest that this novel approach could help mitigate filtrate loss challenges, reduce drilling costs, and enhance the efficiency of geothermal energy production.