2.2.1. Preparation Method for Diutan Gum and Scleroglucan

At room temperature (25 °C), an appropriate amount of biopolymer concentrate was placed in a beaker, a small amount of simulated brine was added, and the solution was stirred at 1000 r/min for 10 min. The remaining simulated brine was added to finalize the solution and it was stirred for another 3 h until the biopolymer was sufficiently dissolved to obtain the biopolymer solution with the target mass concentration. The preparation water not mentioned in the test experiments was simulated brine with a total mineralization of 6 g/L.