California CSLB C-57 Well Drilling Examination

Before mobilizing a drilling rig to a rural residential site, which source should a C-57 contractor consult first to determine minimum setback distances from septic systems and property lines?

• ABulletin 74-81 and 74-90 California Well Standards (DWR)
• BThe California Commercial Driver Handbook
• CFranklin Electric AIM Manual
• DCal/OSHA Title 8 Construction Safety Orders

When evaluating a potential drilling site, what is the primary reason for locating the well upslope and upgradient from existing septic systems?

• AGroundwater flows generally downgradient and could carry contaminants toward a well place…
• BIt reduces the total drilling depth required to reach water
• CIt allows easier access for the drilling rig on level ground
• DIt prevents surface runoff from flooding the wellhead during rain

A contractor is selecting a drilling method for a 400-foot well in consolidated rock with alternating hard and soft layers. Which method is most suitable?

• AAir rotary with down-the-hole hammer
• BBucket auger
• CJetting
• DBored well with hand auger

In a caving, boulder-rich alluvial formation, what is the principal advantage of cable tool drilling over rotary drilling?

• AIt advances the hole faster than air rotary in every formation
• BCasing can be driven down as the hole advances, holding back caving material and boulders
• CIt removes the need for a surface seal, because the driven casing seals the annulus
• DIt produces no cuttings, because percussion pulverizes the formation into the fluid

A contractor estimates the pitless adapter, well seal, and labor for a wellhead at $800 and bids the work with a 25% markup. The work actually costs $1,150. What is the result on this line item?

• ALoss of $150
• BProfit of $150
• CLoss of $350
• DProfit of $200

When estimating drilling cost per foot for a rotary well, which factor most directly affects the per-foot cost in addition to rig day rate?

• ARate of penetration and bit life
• BColor of the drilling fluid
• CBrand of the drilling rig engine
• DDistance to the equipment rental yard only

A well is specified to be drilled to 300 feet with 6-inch diameter steel casing. The drilling contractor charges $45 per foot for drilling and casing installation. What is the estimated drilling and casing cost?

• A$13,500
• B$1,350
• C$135,000
• D$45,000

Which casing material is most commonly selected for a domestic water well in corrosive coastal groundwater with high chlorides?

• APVC plastic casing with solvent-weld couplings
• BBlack steel casing
• CGalvanized steel casing
• DWood stave casing

When selecting a well screen slot size for a gravel-pack well, what should the slot opening be based on?

• AThe grain size distribution of the gravel pack and the formation sand
• BThe total well depth only
• CThe pump discharge diameter
• DThe drilling fluid viscosity

A contractor bids a 250-foot well at $85 per foot. Estimated direct cost is $70 per foot, and lost circulation adds $3,000 of unplanned cost. The bid carried no contingency. What is the result on the job?

• AProfit of $750
• BLoss of $750
• CProfit of $3,750
• DLoss of $3,000

In a well construction estimate, what does the term 'mobilization cost' refer to?

• AThe cost of moving the drill rig, support equipment, and crew to the job site before dril…
• BThe cost of the pump and drop pipe installation
• CThe cost of water quality laboratory testing
• DThe cost of the annular seal material

A geotechnical boring requires continuous sampling to 60 feet in stiff clay. Which sampling method is most appropriate?

• AStandard Penetration Test (SPT) split-spoon sampler
• BShelby tube thin-wall sampler only at specific depths
• CDrive barrel with a cone tip
• DWireline core barrel

What is the minimum annular space typically required around a well casing to properly place an annular seal under California Well Standards?

• AAt least 2 inches
• BAt least 6 inches
• CAt least 12 inches
• DAt least 24 inches

Which of the following is a key consideration when selecting the well diameter for a domestic water supply well?

• AThe pump diameter and required clearance for installation and cooling
• BThe property line setback distance
• CThe color of the casing material
• DThe drilling fluid pH

A 6-inch diameter well casing is installed to a depth of 200 feet. What is the approximate volume of water in the casing when full (1 cubic foot = 7.48 gallons)?

• AApproximately 293 gallons
• BApproximately 117 gallons
• CApproximately 1,470 gallons
• DApproximately 586 gallons

When planning an environmental monitoring well in a contaminated aquifer, what is the purpose of a bentonite seal placed above the screen interval?

• ATo prevent cross-contamination between different aquifer zones
• BTo increase the well yield
• CTo protect the PVC screen from corrosion
• DTo reduce the total drilling depth

Which document must a C-57 contractor file with the California Department of Water Resources after completing a water well?

• AA well completion report (DWR Form 188)
• BA Cal/OSHA incident report
• CA PSI exam fee receipt
• DA driver's license renewal form

A contractor needs to estimate gravel pack quantity for a well with 6-inch casing in a 12-inch borehole, screened from 100 to 200 feet. What is the annular volume to be filled (in cubic feet)?

• AApproximately 58.9 cubic feet
• BApproximately 78.5 cubic feet
• CApproximately 19.6 cubic feet
• DApproximately 117.8 cubic feet

During water well setup, what is the purpose of a conductor casing installed at the start of a rotary-drilled well?

• ATo stabilize the upper borehole and prevent surface material from collapsing into the hole
• BTo serve as the permanent production casing
• CTo replace the need for an annular seal
• DTo function as the well screen

What is the primary purpose of well development after drilling and before pump installation?

• ATo remove drilling fluid, fine particles, and formation damage near the well screen so wa…
• BTo deepen the well beyond the drilled depth
• CTo install the submersible pump
• DTo test the casing for structural strength

Which drilling fluid property is most critical to monitor during mud rotary drilling to prevent caving of the borehole walls?

• ADensity (mud weight) and viscosity
• BColor and odor
• CTemperature
• DpH only

When using direct mud rotary drilling, what happens if the drilling fluid circulation is interrupted for an extended period?

• ACuttings may settle and the borehole may collapse, trapping the drill string
• BThe drilling rate increases
• CThe borehole diameter enlarges uniformly
• DNo effect occurs as long as the rig is running

In cable tool drilling, how are cuttings removed from the borehole?

• ABy bailing with a sand pump or bailer at intervals
• BBy continuous air circulation
• CBy reverse-circulation pumping
• DCuttings are not produced in cable tool drilling

What is the purpose of a gravel pack (filter pack) installed around a well screen?

• ATo filter fine formation sand and stabilize the borehole around the screen
• BTo increase the total well depth
• CTo seal the annular space from surface water
• DTo lubricate the pump

What is the recommended minimum surface seal depth for a water well under California Well Standards in most areas?

• A20 feet below land surface
• B5 feet below land surface
• C50 feet below land surface
• D100 feet below land surface

Which method is used to place an annular seal in a well with a deep seal interval to ensure the seal fills from the bottom up without bridging?

• ATremie pipe placement of grout
• BPouring dry cement from the surface
• CDumping bentonite chips by hand at the surface
• DPumping air down the casing

During well construction, what is a 'telescoped' casing design?

• AA larger surface casing with a smaller diameter production casing installed inside it
• BTwo casings of the same diameter joined together
• CA casing that is perforated throughout its entire length
• DA casing made of two different metals

What is the primary purpose of surge-block development in a newly constructed well?

• ATo agitate the gravel pack and formation, loosening fine particles so they can be removed…
• BTo push the casing deeper into the formation
• CTo measure the static water level
• DTo test the pump motor amperage

When monitoring drilling progress, what does a sudden increase in drilling rate (drilling break) in rotary drilling typically indicate?

• AThe bit has encountered a softer or more fractured formation, possibly a water-bearing zo…
• BThe bit is worn out and needs replacement
• CThe drilling fluid is too viscous
• DThe rig engine is losing power

A driller needs to calculate the static water column pressure at the bottom of a 150-foot well with a static water level at 50 feet below surface (water column height = 100 feet). What is the pressure (1 psi = 2.31 feet of water)?

• AApproximately 43.3 psi
• BApproximately 231 psi
• CApproximately 64.9 psi
• DApproximately 100 psi

What is the purpose of collecting drill cuttings (samples) at regular intervals during drilling?

• ATo construct a geologic log of the formations encountered and identify water-bearing zones
• BTo sell the cuttings as construction aggregate
• CTo test the drill bit sharpness
• DTo measure air temperature in the borehole

During air rotary drilling with a down-the-hole hammer, what carries the cuttings to the surface?

• ACompressed air flowing up the annular space between the drill pipe and borehole wall
• BBentonite drilling mud
• CWater injected at the bit only
• DGravity causes cuttings to fall to the surface

What is the main advantage of reverse-circulation rotary drilling compared to direct mud rotary for large-diameter wells?

• ALarger borehole diameters can be drilled efficiently with borehole stability maintained b…
• BIt requires no drilling fluid
• CIt produces no cuttings
• DIt can only be used in hard rock

A well screen is set from 120 to 180 feet. The gravel pack is specified to extend 5 feet above the top of the screen. At what depth below ground surface should the top of the gravel pack be?

• ATo 115 feet
• BTo 120 feet
• CTo 180 feet
• DTo 185 feet

A contractor needs to calculate the grout volume for an annular seal. The borehole is 10 inches in diameter, the casing is 6 inches in diameter, and the seal interval is 50 feet. What is the approximate grout volume in gallons (1 cubic foot = 7.48 gallons)?

• AApproximately 131 gallons
• BApproximately 204 gallons
• CApproximately 73 gallons
• DApproximately 17.5 gallons

What is a 'naturally developed' well as opposed to a gravel-packed well?

• AA well where the formation itself serves as the filter, developed by removing fine partic…
• BA well that develops water without a pump
• CA well that requires no drilling
• DA well with no casing

What does the term 'specific capacity' of a well refer to?

• AThe yield in gallons per minute per foot of drawdown
• BThe total depth of the well in feet
• CThe casing diameter in inches
• DThe pump horsepower required

After setting the casing, why should the driller centralize the casing in the borehole before placing the annular seal?

• ATo ensure uniform annular seal thickness around the entire casing circumference
• BTo reduce the total depth of the well
• CTo increase the well yield
• DTo eliminate the need for a surface seal

What is the purpose of a pitless adapter in a water well system?

• ATo connect the discharge pipe below the frost line so water exits the well without a pit,…
• BTo pump water from the bottom of the well
• CTo seal the top of the casing
• DTo measure the water level

During well development, what does 'sand pumping' indicate and how should it be addressed?

• ASand entering the well indicates the screen slot size or gravel pack gradation is incorre…
• BSand pumping is normal and should be ignored
• CSand indicates the well is producing at maximum capacity
• DSand means the pump is oversized and should be left alone

What is a 'well screen' and where is it placed in the well assembly?

• AA perforated or slotted pipe section placed across the water-bearing formation to allow w…
• BA solid pipe placed at the surface to protect the wellhead
• CA device to measure the water temperature
• DA cap that seals the top of the casing

A well produces 30 gpm with 15 feet of drawdown after development. What is the specific capacity?

• A2.0 gpm per foot of drawdown
• B0.5 gpm per foot of drawdown
• C450 gpm per foot of drawdown
• D15 gpm per foot of drawdown

In geotechnical drilling, what is the purpose of a Standard Penetration Test (SPT)?

• ATo obtain a disturbed soil sample and measure the resistance to penetration for engineeri…
• BTo install a permanent water supply well
• CTo place an annular seal
• DTo measure groundwater pH

An environmental monitoring well must sample a specific aquifer zone at 80 to 100 feet. What component isolates the screened interval from the rest of the borehole?

• ABentonite seal and fine sand filter pack above and below the screen
• BThe drill bit
• CThe conductor casing
• DThe well cap