Preparation and Performance Evaluation of High Temperature and Salt Resistant Fluid Loss Reducer for Water-Based Drilling Fluids
Aiming at the problem of performance degradation of water-based drilling fluids in deep and ultra-deep well drilling in high-temperature and high-salt environments,a new type of high-temperature and salt-resistant fluid loss agent was synthesized through free radical polymerization.The polymerization conditions were optimized by introducing 2-acrylamide-2-methylpropanesulfonic acid,acrylamide and sodium p-styrenesulfonate as monomers and using N,N'-methylenebisacrylamide as cross-linker.The research results showed that under the conditions of optimal monomer concentration 2.0 mol·L-1,optimal monomer ratio n(AMPS)∶n(AM)=4∶1 and optimal reaction temperature 80℃,the synthesized fluid loss reducer HTSR exhibited excellent performance.The filter loss reduction performance reached 75.2%and maintained a low filter loss(7.8 mL)under high temperature conditions of 200℃.In addition,the filter loss of HTSR in 8%NaCl solution was only 8.6 mL,showing good salt resistance.Thermogravimetric analysis results showed that HTSR had less mass loss before 270℃and had excellent thermal stability.Infrared spectrum analysis further confirmed the correctness of its chemical structure.This study provides new ideas for the design of fluid loss additives for water-based drilling fluids in high-temperature and high-salt environments,and is of great significance to improving the performance of drilling fluids for deep and ultra-deep well drilling.
Water-based drilling fluidFluid loss additiveHigh temperature resistanceSalt resistanceFluid loss reduction performance
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