The mud logger places a sample of calcium carbide in the drillstring when a connection is made. The calcium carbide reacts with the mud to form acetylene gas. The acetylene is detected by a gas detector at the shale shaker after pumping 4,500 strokes. The drillstring is composed of 9,500 ft of 5- in., 19.5-lbm/ft drillpipe and 500 ft of drill collars having an ID of 2.875 in. The pump is a double- acting duplex pump with 6-in. liners, 2-in. rods, and 14-in. strokes and operates at a volumetric efficiency of 80%. a. Estimate the number of pump cycles required to move the gas from the surface to the bit, Answer: 1,400 cycles (neglects gas slip). b. Estimate the number of pump cycles required to move the gas from the bit to the shale shaker. Answer: 3,100 cycles. c. If the penetration rate of the bit is 20 ft/hr and the pump speed is 60 cycles/min., how many feet are drilled by the bit before formation gas expelled from the rock destroyed by the bit travels from the bit to the surface? Answer: 17.2 ft.