Abstract
Given the critical role of polyacrylamide-based Friction Reducers (FRs) in enhancing the efficiency of hydraulic fracturing, this paper aims to provide a comprehensive framework of best practices for evaluating and selecting FRs that account for varying frac fluid compositions, salinity levels, field equipment, logistics, and economic considerations with a focus on the main U.S based shale plays, Permian and Marcellus. High-viscosity friction reducers (HVFRs) are preferable over guar-based systems for applications requiring higher proppant loading due to their enhanced viscosity profiles and breakability to avoid hindering formation productivity by reducing regained conductivity. The paper also introduces a new generation of FRs developed through systematic formulation optimization to withstand extreme frac conditions.
The evaluation process for FRs employs several industry-standard laboratory methods, including flow loop tests, rheometers’ viscosity measurements, and advanced rheology modeling. Specialized tests such as iron stress and shear resistance assessments simulate real-world conditions. The focus is on understanding FR performance in high Total Dissolved Solids (TDS) conditions, particularly those with high divalent concentrations. This study examines the impact of lateral well lengths exceeding four miles, necessitating new FR chemistries and evaluation techniques.
The findings indicate that conventional anionic copolymer FRs significantly underperform in harsh brine conditions, a common condition in many shale plays. This poor performance highlights the need to optimize FR chemistry based on specific brine composition and proppant loading requirements. Both cationic FRs and highly optimized anionic FRs demonstrate superior performance in extremely high salinity conditions, providing viable alternatives. Shear resistance tests reveal that specifically designed FRs can withstand multiple high-shear cycles, indicating their robustness for deployment deep into the toe of the well. Selection from various FR forms—powder, emulsion, or slurry—depends on logistics, site equipment, and operator preferences. Understanding how FR performs in challenging environments ensures more efficient and reliable hydraulic fracturing operations.
This paper provides novel insights into the formulation and application of FRs under extreme conditions, addressing the challenges posed by high TDS and extended lateral well lengths. This paper also provides practical guidance for optimizing FR-based completion fluids by defining critical TDS levels and cation types that require changes in FR chemistry and dosage. The data presented can help operators enhance FR performance and effectively compare and qualify FRs based on their optimal application range and economic efficiency. This comprehensive approach aims to assist operators and field personnel in making informed decisions to improve hydraulic fracturing outcomes.