Well Abandonment and Destruction
What this domain tests
Abandonment questions test whether you can convert a well from a potential vertical conduit back into something close to the natural subsurface condition. Expect permit requirements, sequencing, sealing materials, casing removal or perforation, and documentation.
Why it matters
An open, unsealed borehole connects aquifers. Poor-quality shallow water can drain down the annulus, and confined aquifers can leak upward, sometimes for decades. Destruction must therefore block both the borehole and the annular space, not just cap the top.
Sequence
- Obtain the local destruction permit and confirm the well's construction from the original completion report; if the record is missing, camera or measure the well.
- Remove the pump, wiring, and obstructions, then disinfect and either pull or perforate the casing.
- Pull the casing if it can be pulled. If it cannot, perforate or cut it at closely spaced intervals so grout can escape behind it, and make sure the gravel pack and annulus are sealed too.
- Fill the well from the bottom up by tremie with neat cement grout, cement-bentonite, or bentonite grout, placing sealing material opposite each water-bearing zone so no two aquifers remain connected.
- Seal at least the upper portion with impermeable grout, cap with concrete, and restore the surface so water drains away.
- File the destruction report with DWR, and any local report, within the required time.
Special cases
Flowing artesian wells must be sealed so flow stops permanently. Monitoring wells are destroyed on the same principles, often under a stricter local protocol. Gravel-packed wells fail most often because the pack is left unsealed.
Worked example
A 250-foot domestic well has steel casing to total depth and a gravel pack, and the rig cannot pull the casing. Correct approach: remove the pump, cut or perforate the casing at multiple depths, tremie bentonite or cement grout from bottom to top so grout fills both casing and annulus, place a plug opposite each aquifer, seal the top 20 feet with neat cement, cap with concrete, and file the report. Backfilling with sand and capping would leave a conduit and is not destruction.
Traps that cost marks
- Treating sand or drill cuttings as adequate fill.
- Leaving casing in place without perforation, so grout never reaches the annulus.
- Skipping the permit because the well is already out of service.