Drilling Operations Management
Assignment 2 (Due date: December 5, 2015)
Student ID Number = Name:
1. Galena (lead sulfide) may be used as a weighting material in place of barite. The
specific gravity of galena is 6.8. While drilling an explorational well at the depth of
13,000 ft, your team experienced a gas kick with an intensity of 3 ppg. 12 ppg mud
was in the hole at the time. The well was shut in with a pit gain of 20 bbls. The total
size of the mud system is 2,500 bbls, and the tanks are completely full after taking the
kick.
You decided to dump some mud before starting to add galena to increase the mud
weight to 15 ppg. Keep in mind that the kick will expand as it is circulated out of the
hole. Annular capacity is 0.1 bbls/ft. Use the driller¡s method and make any necessary
assumptions. (50 points)
(1) What is the minimum amount of mud in bbls that must be dumped prior to adding
the galena (to avoid any loss of galena due to the tank overflow) ?
(2) How much galena must be added in tons ?
(3) Use the market value and determine cost of galena?
2. There is a float valve in the drillstring. Please describe how you would go about
finding the true SIDPP. Include a sketch in your solution. (50 points)
3. A well is drilled at a vertical depth of 12,200 ft. 12 ppg mud is being circulated at 9
bbls/min when the well begins to flow. Over a 5-minute interval, there is a pit gain of
15 bbls. The well is closed in and the drillpipe pressure stabilizes at 400 psi. At that
time the casing pressure is 550 psi. The annular capacity is 0.0775 bbls/ft outside the
5-inch OD drillpipe, and 0.035 bbls/ft outside the 600 ft of 3-inch ID drill collars. The
drillpipe ID is 4.276 inches. Annular capacity inside the casing is also 0.0775 bbls/ft.
(50 points)
(1) What is the density of the kick material in ppg assuming the kick entered the
annulus as a single slug ?
(2) What is the density of the kick material in ppg assuming the kick mixed with the
mud pumped during the detection time ?
(3) What is the pressure in psig at the casing depth of 4,000 ft when the top of the
kick zone gets there, assuming that the driller¡s method is used ? Use the kick
density calculated in problem (2) above.
(4) What is the casing pressure in psig at the surface when the top of the kick zone
gets there, assuming that the driller¡s method is used ?
(5) What is the pressure in psig at the casing depth of 4,000 ft when the top of the
kick zone gets there, assuming that the engineer¡s methods is used ?
4. When circulating a kick out of the hole in floating drilling, the choke line is used
because the marine riser does not have sufficient pressure capability. However, this
can lead to excessive pressure drop in the choke line. To reduce this pressure drop it is
not unusual that both the choke and the kill lines are used in parallel for circulating
the kick out.
When the A+ Drilling Co. Rig #11 was handling this kind of a kick, the 4-inch ID choke
line was being used and the total frictional pressure drop in the choke line was 1,000 psi.
Part of the flow was diverted through the 3-inch ID kill line. What was the new pressure
drop when flow took place up both lines at the same time ? The pump rate did not
change. (50 points)