As shown in Fig. 2, mud viscosity increased immediately
after addition of GLG. Moreover, mud viscosity
increased significantly after heating. For example, at
moderate shear rate (50/s), the base mud demonstrated a
viscosity of 42 cP. After adding GLG, mud viscosity
increased to 71 cP. After heating, mud viscosity jumped to
240 cP. This phenomenon agrees with previous finding:
GLG forms soft gel at elevated temperature (Kelco 2007).