4. We are drilling at 10000 ft in a formation with 20% porosity, 30% water saturation and 70% gas saturation. The temperature is 640 R, and the mud density is 11 ppg. The gas gravity is .72. The drilling rate is 100 ft/hr with a 12 % inch bit. The circulation rate is 300 gpm. Formation water is 9.04 ppg, and formation rock density is 26 ppg. a. What is the mud density at the surface? Ppg b. What is the average density of the annular mud? c. At what rate (SCFD) will gas be liberated at the surface?

Fig: 1