I'm having a really hard time coming up with the asnwers for these and I was wondering if any of you could help me out.
Thanks
1) A drillstring is composed of 12,000 ft of 51/2-in., 21.90-lbm/ft drillpipe and, 1,800 ft of drill
collars having an ID of 5-in. and an OD of 9.375-in. Compute the following items:
a.Capacity of the drillpipes in barrels.
b.Capacity of the drill collars inbarrel.
c. Number of pump cycles required to pump surface mud to the bit. The pump is a duplex double acting with 7.25-in. liners, 3.25-in. rods, 22-in. strokes, and operates at a volumetric efficiency of 85%.
d. Displacement of drillpipe in bbl/ft.
e. Displacement of drill collars in bbl/ft.
f. Loss in fluid level in the well if 10 stands of drillpipe are pulled without filling the
hole. The ID of the casing in the hole is 10.772in., the length of each pipe joint is 30 ft., and assume there are 3 joints per each stand.
g. Loss in fluid level in the well if 1 stand of drill collars are pulled without filling the hole. The ID of the casing in the hole is 10.772 in., the length of each collar joint is 30 ft., and assume there are 3 joints per each stand.
h. Change in the fluid level in the pit if the pit is 12 ft. wide and 20ft. long, assuming the hole is filled after pulling 10 stands of drillpipe.
i. Change in the fluid level of a 4*4ft. trip tank assuming the hole is filled from the trip tank after pulling 10 stands of drillpipe
2) The penetration rates using gas, foam, and mud in and area are 25 ft/hr, 15 ft/hr, and 10 ft/hr respectively. If gas is used, each water zone encountered must be sealed off. The cost of the plugging treatment is $1,500, and 12.5 hours of rig time are required to complete the sealing operation. The normal operating cost for air drilling is $125/hr. The use of foaming agents requires an additional $75/hr. The normal operating cost when using mud is $100/hr. Regardless of the drilling fluid used, the average bit cost is $900. The average bit life is 25 hours and the average trip time is 10 hours. Determine which drilling fluid yields the lowest cost if four water zones are encountered per 1,000 ft. drilled.
3)A 11.75 ppg freshwater mud has a solid content of 23 vol. %.
a.Calculate the volume fraction of API barite and low-specific- gravity solids in the mud.
b. Calculate the weight fraction of API barite and low-specific-gravity solids in the mud.
c. Calculate the API barite and low-specific-gravity solids content in pounds per barrel
4)The density of 650 bbl of 13.5 ppg mud must be increased to 15 ppg using API barite. In order to maintain an acceptable mud consistency, 1 gallon of water is added per sack of barite. The total mud volume is limited to 650 bbl. Calculate the volume of old
mud that should be discarded in bbl, the mass of required barite in lbm , and the volume of water (in bbl) that must be added to maintain the consistency.
5) t is desired to increase the density of a Class C cement to 15.5 ppg by adding
barite. Using the water requirement for class C cement and barite, compute the followings:
a.Weight of barite in lbm. that should be blended with each sack of cement.
b.The yield of slurry
c.“percent mix” of the slurry
6)A casing which has an OD of 11.75-in. and an ID of 10.772-in. is to be cemented at a depth
of 12,000 ft. A 40-ft shoe joint is used between the float collar and the guide shoe. Only 2,500 ft of the annulus is going to be cemented. Each sack of class H cement is mixed with 10.5 gal of water to which is added 25% CaCl2 (by weight of water). The hole is drilled with a 13 3/4in. bit. Compute the followings assuming an excess factor of 1.80:
a. Slurry density in ppg.
b. Yield of slurry
c. Slurry volume required for this cementing job
d. Number of sacks of cement required
Reply With Quote
Bookmarks