CA Well Driller flashcards
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32 cards. Read the term and the definition here. The deck at the top of this page is optional.
- Annular surface seal
- Low-permeability grout placed in the space between borehole wall and casing, extending from land surface to the required depth to block surface and shallow groundwater.
- Approved seal materials
- Neat cement, cement-sand grout, bentonite grout, and bentonite chips or pellets. Drill cuttings and native soil are not acceptable seal materials.
- Tremie grouting
- Placing grout through a pipe from the bottom of the space upward so it displaces water and fills continuously without voids or bridging.
- Centralizer purpose
- Keeps the casing string centered off the borehole wall so the annular seal forms a continuous barrier rather than a thin channel.
- Mud rotary circulation
- Drilling fluid cools the bit, lifts cuttings, and holds the borehole open. Mud weight must exceed pore pressure but stay below fracture pressure.
- Reverse circulation drilling
- A dual-wall pipe returns cuttings inside the inner pipe, giving cleaner samples, faster penetration, and less plugging in large-diameter wells.
- Cable-tool drilling
- A heavy bit is lifted and dropped to fracture and loosen formation, and cuttings are removed by bailing. Suits alluvium but is slow in hard rock.
- Wellhead sanitary completion
- A watertight, vermin-proof cap plus a sanitary seal at the casing top, excluding surface water, insects, and rodents from the well.
- Casing depth rating
- Casing must be new and undamaged, with pressure and collapse ratings adequate for the installed depth. PVC casing ratings limit how deep it can be set.
- Aquifer isolation by casing
- Where multiple aquifers are penetrated, casing and seal isolate each so poor-quality water cannot migrate into a usable aquifer.
- Specific capacity
- Pumping rate divided by drawdown, in gpm per foot. A declining value over time signals plugging, screen corrosion, or aquifer decline.
- Drawdown definition
- The difference between static (non-pumping) water level and pumping water level, both referenced to a stated measuring point such as top of casing.
- Step-drawdown test
- Pumping at successively higher rates and plotting drawdown against discharge to separate aquifer loss from well loss and assess well efficiency.
- Well development goal
- Remove drilling fluid, fines, and filter cake from the gravel pack and screen until the well yields clear water at maximum specific capacity.
- Development methods
- Surging, backwashing, jetting, air-lift pumping, and overpumping, each run until discharge runs clear and sand content stabilizes.
- Well disinfection
- A chlorine solution giving a measurable residual throughout the well, held for a contact period, then pumped to waste until residual clears.
- Bacteriological sampling
- Samples are collected after chlorine is purged, with the pump running, using sterile containers and aseptic technique to avoid contamination.
- Abandonment objective
- Restore the borehole so water cannot move between aquifers and surface water cannot enter the well or aquifer.
- Abandonment sequence
- Remove or perforate obstructions, fill the well bore and annular space with approved sealing material, and seal the top with a durable cap.
- Perforating abandoned casing
- Casing that cannot be removed is perforated or ripped at intervals so seal material can pass behind it and bond to the formation.
- Temporary out-of-service well
- A well not abandoned must still have a watertight, vermin-proof cap and remain accessible for inspection.
- Destruction report contents
- Documents the well identity, sealing method, materials and volumes used, and sealing depths, filed with the required agencies.
- C-57 license
- The Contractors State License Board classification for water well drilling, required to drill, deepen, repair, or abandon a water well in California.
- Well completion report
- Filed with DWR for new wells, with copies to the local enforcement agency, documenting location, driller and license number, casing, screen, seal, and yield.
- Local enforcement agency
- Typically the county environmental health department, which issues well permits, inspects construction, and may impose stricter setbacks and seal depths.
- Owner-builder exemption
- Allows a property owner to drill on their own land only; it does not cover work for others or work performed for compensation.
- State versus local standards
- DWR water well standards bulletins set the state baseline, but county or city ordinances may impose stricter requirements that govern the site.
- Report filing failure
- Drilling without a permit or failing to file required reports can bring permit denial, fines, or license discipline by CSLB.
- Pilot hole logging
- Drilling and logging a smaller hole before reaming confirms depth to water-bearing zones and guides casing and screen placement.
- Bentonite chip seal
- Chips or pellets placed in increments and hydrated in the annular space, kept free of bridging, and capped with grout or concrete where required.
- Sand content check
- Measured at the discharge after development; persistent sand indicates an undersized screen slot or incomplete development.
- Grout through standing water
- Grout must not be poured from the top through standing water; positive placement from the bottom up is required to avoid dilution and voids.