General Questions With Answers - 3 -

1. What is the difference betwen a counter balanced drum and a smooth drum? 

2. While circulating out a kick during first circulation of drillers method Pst ( DrillPipe Pressure) was held constant. After a while the pump speed was decreased while hold the same Pst by adjusting the choke. Explain what happens to the bottom hole pressure.

3. Which of the follwing threaded connections are the same as 4½ IF

a. 5 XH
b. NC38
c. 5DSL
d. NC50

4. If the string volume is greater than the open hole annular volume. Which kill method will give lower shoe pressures and why? (Explain your answer). What is the preferred kill method in these situations and why?

5. Which pressure is used for calculating pore pressure (casing pressure Pc or drill pipe pressure Pdp) and why?

6. When tripping out of hole using an accurate trip tank for keeping the hole full, will the amount of mud that is actually added to the hole be equal to, greater than or less than the volume of steel removed? (Explain your answer ).

7. To run casing you string up 12 lines instead of 10. Neglecting line weight, is the load on the derick the same, less or more?

8. In what phase of killing is Pchoke the highest? What effect will kill mud have on this highest pressure?

9. Annular volume is less than the string volume. Which method : Drillers method or Weight and Wait method will give the highest Pchoke pressures.


1. The drum surface is either smooth or grooved. A counterbalance drum has a grooving pattern which allows spooling of the wire to be controlled and prevents deformation of the wire. a smooth drum has not got this spooling control and needs one full layer of wire to prevent any force on the wire clamp in the drum.

2. If you decrease the pump speed and keep the pressure constant you will have to close the choke to do so. If you close the choke you will increase the BHP.

3. 4 1/2 IF = 5 1/2 DSL = 5 XH = NC 50

4. None. Both Drillers and Wait and Weight Method will have the same shoe pressure if the drillstring volume is larger than the open hole volume. The Kill mud is not yet in the annulus to reduce the shoe pressure when using the Wait and Weight method.

5. Pdp is used, because the Pann has an influx in the hole with an unknown density.

6. It should be theoretically be the same volume. However there will be mud which will cling on the inside of the pipebody. This will make the volume of mud to be added to the system slightly larger.

7. Static Derrick load  with 10 lines = (N+2)/N = (10+2)/10 = 1.2 x Hook load

With 12 lines, The Static Derrick load = (N+2)/N = (12+2)/12 = 1.1667 x Hook load

Therefore the load is less with 12 lines than 10 lines

8. The highest pressure during a gas kick is when the gas reaches the choke. The kill mud reduces the choke pressure because of the extra hydraustatic head in the annulus.

9. Both methods will give the same Pchoke. The heavier kill mud has not reached the annulus and the influx is already out of the hole.

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