Research of Na₂CO₃/C₁₂H₂₅SO₄Na modified bentonite on high dispersion performance

Abstract

The dispersion performance of drilling fluids at high temperatures has always been a bottleneck in the research. To improve the dispersion of drilling fluid at high temperature and pressure, the natural Ca-based bentonite was modified with Na₂CO₃ and SDBS (sodium dodecyl benzene sulfonate: C₁₂H₂₅SO₄Na) by microwave semi-dry method. The effects of the ratio of Na₂CO₃ to SDBS, radiation time, initial temperature and microwave power on the modification were investigated. In addition, the microstructure of the samples was obtained using infrared spectroscopy (FTIR) and scanning electron microscopy (SEM), and the results showed that Na₂CO₃/SDBS was successfully inserted into the bentonite. In addition, the dispersion performance of the modified bentonite was evaluated in this paper, and the gelling value of the modified bentonite was 525 ml/15 g with an apparent viscosity of 22.5 mPa·s. The modified bentonite was compared with drilling-grade Na-based bentonite. The fluid loss (FLHTHP) of modified bentonite at high temperature and pressure is only 8 mL, the mud productivity is up to 25.71 m³/t, and the kinetic plastic ratio of modified bentonite is 1.5. The modified bentonite has better dispersion performance at high temperature and pressure.

Keywords
Bentonite; Anionic surfactants; Dispersion; Drilling fluid; Modification