Preparation of temperature-sensitive CMC-BENTONITE-NIPAM applied to deepwater drilling fluids

Abstract

ABSTRACT Chemically modified bentonite has greatly improved its performance due to its structural adjustability. In this study, the modification of bentonite was accomplished through the method of sodium intercalation adsorption. The temperature-sensitive modified bentonite was prepared by initially sodifying bentonite with sodium carbonate and sodium pyrophosphate, intercalating CMC into the interlayer structure of sodified bentonite, and adsorbing N-isopropyl acrylamide (NIPAM) on the surface of bentonite. Further, the deep-water bentonite drilling fluid system was prepared. The optimal sodification conditions were determined by the single-factor control variable method of expansion volume as a drug-bentonite ratio of sodium carbonate of 1:9 and an addition amount of sodium pyrophosphate of 0.5%. The ratio of sodified bentonite to CMC drug-bentonite is 30:1. The addition amount of NIPAM was determined to be 0.5 g through the orthogonal experiment method of two factors of temperature and viscosity. Meanwhile, the temperature-sensitive modification mechanism and performance changes were analyzed through microscopic characterization and performance testing. The results show that the modified bentonite can play a significant temperature regulation role within the temperature range of 60°C and above, and the prepared drilling fluid system has good rheological properties under the condition of temperature change.