Risk Assessment & Management Flashcards

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

Answer: Potential cross-contamination of the aquifer

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

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

Answer: Uncontrolled blowout and potential borehole collapse

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

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

Answer: Driller's log from a nearby well

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

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

Answer: Hydraulic connection between aquifers of different quality

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

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

Answer: 3 feet

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

Which hazard classification applies to a drilling site located within a 100-year floodplain?

Answer: High risk — well construction standards must address flood inundation

Drilling in a 100-year floodplain is high-risk because floodwaters can inundate and contaminate a newly constructed well, requiring elevated wellhead designs.

What is the purpose of a pre-task Job Hazard Analysis (JHA) on a drilling site?

Answer: To identify, evaluate, and control hazards before work begins

A JHA systematically identifies potential hazards for each task step and assigns controls to reduce or eliminate risk before work starts.