Thermoresponsive Bentonite for Water-Based Drilling Fluids

Abstract

As an important industrial material, bentonite has been widely applied in water-based drilling fluids to create mud cakes to protect boreholes. However, the common mud cake is porous, and it is difficult to reduce the filtration of a drilling fluid at high temperature. Therefore, this paper endowed bentonite with a thermo response via the insertion of N-isopropylacrylamide (NIPAM) monomers. The interaction between NIPAM monomers and bentonite was investigated via Fourier infrared spectroscopy (FTIR), isothermal adsorption, and X-ray diffraction (XRD) at various temperatures. The results demonstrate that chemical adsorption is involved in the adsorption process of NIPAM monomers on bentonite, and the adsorption of NIPAM monomers accords with the D–R model. With increasing temperature, more adsorption water was squeezed out of the composite when the temperature of the composite exceeded 70 °C. Based on the composite of NIPAM and bentonite, a mud cake was prepared using low-viscosity polyanionic cellulose (Lv-PAC) and initiator potassium peroxydisulfate (KPS). The change in the plugging of the mud cake was investigated via environmental scanning electron microscopy (ESEM), contact angle testing, filtration experiments, and linear expansion of the shale at various temperatures. In the plugging of the mud cake, a self-recovery behavior was observed with increasing temperature, and resistance was observed at 110 °C. The rheology of the drilling fluid was stable in the alterative temperature zone (70–110 °C). Based on the high resistance of the basic drilling fluid, a high-density drilling fluid (ρ = 2.0 g/cm3) was prepared with weighting materials with the objective of drilling high-temperature formations. By using a high-density drilling fluid, the hydration expansion of shale was reduced by half at 110 °C in comparison with common bentonite drilling fluid. In addition, the rheology of the high-density drilling fluid tended to be stable, and a self-recovery behavior was observed.

A Comparative Study on Color Stability of Anthocyanin Hybrid Pigments Derived from 1D and 2D Clay Minerals

“…FTIRs pectra of Kal, Mt, Hal, Sep, and the corresponding hybrid pigments are shown in Figure 2. The absorption bands at around 3700–3500 cm −1 and at ~3400 cm −1 were mainly ascribed to the stretching vibration of O-H groups belonging to Al(Fe,Mg)-OH and H 2 O (zeolitic H 2 O) [26,36,41,42,43], bound OH 2 [44], structural OH, and adsorbed water [31,45], respectively (Figure 2a). The bending vibration of H 2 O was located at around 1630 cm −1 .…”

An Investigation on the Function of Mud Cakes on the Inhibition of Low Molecular Inhibitor for Water-Based Drilling Fluids

“…Further, the BET (Bentonite) specific surface area and size of nano-silica particles were 150 m 2 /g and 7-40 nm, respectively. Apart from that, a popular 1,6-hexamethylenediamine (HMDA) inhibitor was added to inhibit the hydration of clay minerals [27], which was obtained from Sigma-Aldrich and was satisfied with chemical analysis.…”

“…Four drilling fluids, such as 1#, 3#, 5# and 7#, were prepared in this way. In contrast, each of the previous four drilling fluids was stirred with 3 wt% HMDA inhibitor for 2 h to inhibit the hydration of wellbores during drilling [27]. The other four drilling fluids, 2#, 4#, 6# and 8#, were prepared in this way.…”

Polymeric structure-forming agent for drilling muds

“…Essential assumption of the realized project is development of mud system that allows drilling whole depth of the borehole with only one mud without necessity of its change. First stage of the project consist of design of a base mud which permit its rheological properties adjustment to encountered geological conditions [1][2][3][4][5][6].…”