NGWA GENERAL DRILLING EXAM (ACTUAL 2025/2026) STUDY
QUESTIONS AND VERIFIED CORRECT ANSWERS
Who is the most qualified person to design a well?
Hydrogeologist.
In proper well design...
... well screen intake velocity should be less than 1'/second
Reduced yield from a water-bearing formation can be caused
by...
... screen incrustation.
The diameter of a screen is not a critical factor in the specific
capacity. Double the diameter of a screen generally increases
the specific capacity by what percent?
7% to 10%.
When drilling in an unfamiliar area, the collection of samples...
... can enable the ground water professional to correlate
formations from one area to another.
, A well screen...
1. Is a filtering device.
2. Permits water to enter the well from the saturated aquifer.
3. Precent sediment from entering the well.
(T/F) Gravel-packed wells should be sealed at the top of the
gravel pack as well as in the annulus.
True.
(T/F) Dry cement may be mixed with water in the annulus to
form an acceptable surface seal.
False.
Pressure grouting requires that the grout must be...
... under sufficient pressure to drive it into the zone to be
grouted.
When only 40' of cement is required to grout the surface
casing, one can achieve a good seal by...
QUESTIONS AND VERIFIED CORRECT ANSWERS
Who is the most qualified person to design a well?
Hydrogeologist.
In proper well design...
... well screen intake velocity should be less than 1'/second
Reduced yield from a water-bearing formation can be caused
by...
... screen incrustation.
The diameter of a screen is not a critical factor in the specific
capacity. Double the diameter of a screen generally increases
the specific capacity by what percent?
7% to 10%.
When drilling in an unfamiliar area, the collection of samples...
... can enable the ground water professional to correlate
formations from one area to another.
, A well screen...
1. Is a filtering device.
2. Permits water to enter the well from the saturated aquifer.
3. Precent sediment from entering the well.
(T/F) Gravel-packed wells should be sealed at the top of the
gravel pack as well as in the annulus.
True.
(T/F) Dry cement may be mixed with water in the annulus to
form an acceptable surface seal.
False.
Pressure grouting requires that the grout must be...
... under sufficient pressure to drive it into the zone to be
grouted.
When only 40' of cement is required to grout the surface
casing, one can achieve a good seal by...
