4.50 It is desired to estimate the proper pump operating conditions and bit nozzle sizes for maximum jet im- pact force at 1,000-ft increments for an interval of the well between surface casing at 4,000 ft and in- termediate casing at 10,000 ft. The well plan calls for the following conditions. Mud Plastic Yield Depth Density Viscosity () Point (ft) (Ibm/gal) (lbf/100 sq ft) 5,000 6,000 7,000 8,000 9,000 10.0 25 10.0 10.0 11.0 12.0 25 25 30 5.0 5.0 5.0 6.0 8.0 35 Pump horsepower, hp Pump efficiency Maximum pump pressure, psig Minimum annular velocity, f/min Drillpipe, in. OD x in. ID Drill collars (7.5-in.-OD x 2.75-in.-ID), ft Hole size (washed out). in. Casing ID, in. Surface equipment equivalent to 140 ft of drillpipe 1,250 0.85 3,200 100 4.5x3.826 600 10.05 10.05