3.15 A well is being drilled and a mud weight of 17.5 lbm/gal is predicted. Intermediate casing has just been set in 15 lbm/gal freshwater mud that has a solids content of 29%, a plastic viscosity of 32 cp, and a yield point of 20 lbf/100 ft2 (measured at 120F). What treatment is recommended upon in- creasing the mud weight to 17.5 lbm/gal?