Introduction to Underbalanced Drilling


1. During underbalanced drilling, the hydrostatic pressure of the drilling fluid column in the wellbore is _ the formation pressure.

A .less than
B .more than
C .equal to

2. Which of the following is NOT one of the potential benefits of underbalanced drilling?

A .Reduced formation damage
B .Increased penetration rate
C .Increase in reserves
D .Increased bit life
E .Reduced lost circulation

3. Coiled tubing systems are commonly used in underbalanced drilling operations.

A .True
B .False

4. What type of drilling fluid was used in the early applications of underbalanced drilling?

A .Foam
B .Nitrogen
C .Carbon dioxide
D .Compressed air

5. Which of these is NOT a typical fluid density used in underbalanced drilling?

A .0.9 pounds per gallon
B .2.5 pounds per gallon
C .4.5 pounds per gallon
D .10 pounds per gallon

6. It is possible to obtain underbalanced conditions with conventional drilling liquids.

A .True
B .False

7. The speed of a pressure wave through a static fluid column is equal to

A .the speed of light in the same medium.
B .the speed of electromagnetic propagation in the same medium.
C .the speed of sound in the same medium.

8. Under what condition would you prefer the ECD technique over the choke-pressure control method?

A .Casing is set down to bottomhole.
B .Casing is set at a shallower depth.

9. What is the relationship between circulation rate and ECD?

A .The greater the flow resistance, the lower the ECD.
B .The greater the flow resistance, the higher the ECD.
C .There is no relationship.

10. Which of the following is NOT among the primary types of fluids used in underbalanced drilling operations?

A .Gaseous
B .Liquid
C .Plasma
D .Two-phase

11. Gas-to-liquid volume at standard conditions is a measure known as

A .Quality
B .Ratio
C .Specific volume
D .Specific density

12. It is possible to generate nitrogen supplies for underbalanced drilling by extracting the N2 from the air stream.

A .True
B .False

13. What type of drilling fluid system has a gas-to-liquid ratio of 200?

A .Gasified liquid
B .Foam
C .Mist

14. Which phase has a continuous structure within foam?

A .Solid
B .Gas
C .Liquid

15. A parasite string is a separate flow path that is run inside the casing.

A .True
B .False

16. Since there is no filter cake around the wellbore, the chance of differential sticking is minimized in underbalanced drilling.

A .True
B .False

17. Underbalanced drilling also minimizes the risk of blowout, fire or explosions.

A .True
B .False

18. Which of the following type of fluid is more complicated to model?

A .Incompressible
B .Slightly compressible
C .Fully compressible

19. A decrease in the bottom hole pressure typically causes:

A .no change in penetration rate.
B .lower penetration rates.
C .higher penetration rates.

20. What is the detrimental effect of mud ring formation?

A .Hole stability problems
B .Downhole fires
C .Differential sticking
D .A, B and C

Previous page 1 2 3 4

Related Articles

Leave a Reply

Your email address will not be published. Required fields are marked *

Back to top button