Polyamino Acid Grafted Modified Nano Biochar as an Environmentally Friendly Shale Inhibitor in Water-Based Drilling Fluid

Aiming at the problems of unsatisfactory inhibition effect and poor high temperature resistance of environmentally friendly shale inhibitors, polyamino acid grafted modified nano biochar shale inhibitor (JL-BC) was synthesized from arginine, lysine and nano biochar (BC) for the first time, which was non-toxic and easily degradable with a temperature resistance of 220 ℃. The inhibition performance and inhibition mechanism of JL-BC were evaluated and analyzed by a series of experiments. The results showed that JL-BC was more effective than potassium chloride (KCL) and polyether amine (PEA) in inhibiting the hydration swelling of sodium bentonite (Na-BT) and the hydration dispersion of shale cuttings at high temperatures. JL-BC could strongly adsorb and wrap on the surface of Na-BT, increase the particle size of Na-BT, neutralize the negative charge on the surface of Na-BT, and reduce the absolute value of zeta potential of Na-BT. In addition, the EC50 of luminescent bacteria of JL-BC was 292,948 mg/L and the BOD5/CODcr was 32.1%, indicating that it was non-toxic and easily degradable.