Foam Drilling | What is Foam Drilling?
Assessment
1. Which of the following is NOT a characteristic of foam?
A .Extremely high viscosity
B .Low density
C .Stability at high temperature ✔
D .Large lifting capacity
2. Which of the following bubble shape configurations minimizes the liquid volume required to form films between bubbles?
A .Spherical shape
B .Pentagonal dodecahedra (twelve-sided) shape ✔
C .Cylindrical shape
3. A seventy percent quality foam is composed of:
A .seventy percent liquid by volume
B .seventy percent gas by volume ✔
C .None of the above
4. It is possible to generate stable foams at high qualities of around 99 percent.
A .True ✔
B .False
5. The pressure within a gas bubble is __ proportional to its size.
A .directly
B .inversely ✔
6. What is the measure of foam stability?
A .Half-life ✔
B .Surface area
C .Specific gravity
D .None of the above
7. What is the most effective way of destroying high quality foams?
A .Ionic agents
B .Mechanically ✔
C .Iso-octanal alcohol
8. Which of the following statements is NOT true about how the formation fluid inflow would affect drilling foam properties?
A .Increases density
B .Reduces viscosity
C .Increases interfacial tension ✔
D .Reduces foam quality
9. The overall foam viscosity is independent of the foaming agent’s concentration.
A .True ✔
B .False
10. For stable foams most of the increase in lifting force occurs as the quality is increased beyond:
A .30 percent
B .50 percent
C .80 percent ✔
11. Under what conditions is the terminal velocity independent of the foam’s viscosity?
A .When the flow is laminar
B .When the flow is turbulent ✔
C .When the flow is transitional
12. Foam drilling typically requires more compression power compared to dry air drilling.
A .True
B .False ✔
13. The compressors used in foam drilling are typically ________ those used in dry air drilling.
A .larger than
B .smaller than ✔
C .same size as
14. What is the volumetric capacity of a typical portable foam drilling unit?
A .650 to 1,500 scf per minute ✔
B .2000 to 3500 scf per minute
C .3000 to 5000 scf per minute
15. Most surfactants used as foaming agents are bio-degradable.
A .True ✔
B .False
16. One way of destroying foam at the surface is by __ its pH.
A .increasing
B .reducing ✔
C .neutralizing
17. A dry foam takes longer to decay and requires more defoamer.
A .True
B .False ✔
18. Generally, most of the foam in the annulus collapses while making a connection.
A .True
B .False ✔
19. Which of the following is NOT a limitation of foam drilling?
A .Poor water lifting capacity ✔
B .Corrosion
C .Wellbore instability
D .Cost of consumables
E .Waste water disposal
20. Foams generated by ___________ completely eliminate the chances of downhole fire.
A .air
B .natural gas
C .hydrogen
D .inert gases ✔
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