1. If the average density of the sediments in the Gulf of Mexico is 2.17 gm/cc and the water depth at the wellsite is 4000 ft, what are the expected overburden, pore and effective pressures and temperature at the reservoir depth of 15,000 ft below sea bottom or depth below mudline?
2.What weight (lbs/gal) drilling mud would be required to balance the expected formation pressure at this depth?
3. Overpressure is commonly encountered when drilling in the Caspian Sea. Log measurements from a nearby well indicate that the average sediment density changes from 2.18 gm/cc to 2.35 gm/cc at a depth of 8000 ft below mud line. Log measurements also indicate that the thermal gradient is 1.80 oF/100 ft. The nearby well suffered a blowout and recorded formation pressures of 12,000 psi. The water depth at your location is 400 ft and bottom temperature is 17 oC. Your target depth is 15,000 ft. Calculate the overburden, pore and effective pressures and temperature you would expect. Calculate the required safe mud weight (lbs/gal) to prevent a blowout.