Enhanced Filtercake Removal Technology for Improved Operational Flexibility

Abstract This paper introduces a new generation of filtercake removal fluids that overcome the limitations of conventional systems used in the oil industry. Current practices involve using delayed-reaction cleanup fluids to homogeneously remove drilling mud filtercake from extended laterals. These systems are however capable of only operating within a narrow time frame of less than 24 hours which poses challenges, especially at elevated temperatures. This paper aims to address this constraint by presenting a novel dual-phase filtercake removal fluid system capable of delaying reaction for several days. To achieve this goal, a comprehensive experimental program involving laboratory tests of the newly formulated emulsified filtercake removal fluid system was carried out at HPHT conditions. Specifically, the fluid was assessed for effectiveness in dissolving filtercake generated from water-based mud comprising of acid-soluble solids and polysaccharide polymers. The samples were subjected to varying soaking times ranging from 1 to 10 days. During this time, the samples were monitored for thermal stability via turbidity sensors, solubility, and measured their corrosivity on C-95 carbon steel metallurgy. Extensive experimentation yielded encouraging outcomes. Notably, the dual-phase filtercake removal fluid demonstrated remarkable thermal stability at temperatures up to 210°F for 8 days. Moreover, it successfully dissolved increasing amounts of the filtercake from 24% to 51% during the respective soaking intervals, showcasing its ability to gradually break down complex deposits over an expanded timeframe. Additionally, lab investigations revealed minimal corrosivity toward typical tubular metallurgies, thereby alleviating concerns about equipment integrity. Collectively, these positive findings suggest that our innovation holds considerable promise for improving operational efficiencies and reducing downtime associated with current filtercake removal methodologies. Unlike earlier approaches limited by short soaking times of no more than 24 hours, the proposed breakthrough formulation provides operators greater operational flexibility to conduct the necessary tasks in a safe manner. Thereby, potentially leading to increased resource recovery, reduced costs, and more streamlined workflows – all critical factors influencing project profitability and sustainability.