CWD Risk Assessment & Management 2

Question 1

When drilling near an underground storage tank (UST), what is the PRIMARY risk assessment concern?

Accepted Answer

Potential cross-contamination of the aquifer

Answer

USTs can leak petroleum hydrocarbons that may contaminate the aquifer if drilling penetrates contaminated soil or connects pathways to groundwater.

Question 2

A driller notices unexpectedly high artesian pressure during well construction. What is the most critical immediate risk?

Accepted Answer

Uncontrolled blowout and potential borehole collapse

Answer

Uncontrolled artesian flow can cause blowout, borehole collapse, and flooding of the work area, posing serious safety and environmental hazards.

Question 3

Which document is essential for identifying subsurface hazards BEFORE drilling begins on a new site?

Accepted Answer

Driller's log from a nearby well

Answer

Nearby driller's logs reveal formation sequences, aquifer depths, and known hazards such as lost circulation zones or contaminated intervals.

Question 4

What risk does drilling through a confining layer (aquitard) pose if not properly managed?

Accepted Answer

Hydraulic connection between aquifers of different quality

Answer

Breaching a confining layer can allow poor-quality water from one aquifer to migrate into a better-quality aquifer, causing permanent contamination.

Question 5

Under OSHA regulations, what is the minimum safe distance workers must maintain from an unsupported borehole edge?

Accepted Answer

3 feet

Answer

OSHA requires workers to remain at least 3 feet from the edge of an unsupported excavation or borehole to prevent falls.

(CWD) Certified Well Driller Practice Test