Well Installation

Reading

USGS Water Resources Investigation report 96-4233, Selection and Installation of wells
http://water.usgs.gov/owq/pubs/wri/wri964233/

Driscoll - Groundwater and Wells
This is the bible of drilling, has good pictures. It is written for water supply wells.

Design and Installation of Monitoring Wells (topics covered)
     Well design
     Sizing
     Casing and screen selection
     Well drilling methods
     Grouting
     Formation and filter packs
     Well development
     Documentation

Well design
How do you want to place your wells to get adequate information?
Open boreholes
Single screened wells -
Well clusters -
Multiple screened wells
Other techniques

Well Size
How big should the well be?
How bog should the hole be?

Casing
What characteristics are important for casing and screens?
What materials should be used?
How should the well be assembled?
How long should the screen be?
What type of screen openings?
Should you use a filter wrap?
What about pre-packed screens?
How do you size your screen slots?

Well drilling methods
When do you need to decontaminate?
How can you decontaminate equipment?

How big should the borehole be relative to the casing size?

How do the drilling methods below work?
In what geologic settings can they be used?
What are the advantages, disadvantages of each?
Rotary
Direct with mud
Reverse circulation
Dual-wall reverse circulation
Direct air
Cable tool
Vibration
Driven wells
Jetting
What is the purpose of drilling fluids?
What kinds are there? What is used for each method?
How can you estimate viscosity needed?

Grouting/Filter pack
How do you finish the well?
What is the purpose of a filter pack?
What materials are suitable?
How should a well be grouted?

Well development
Why develop a well?
Should all wells be developed?
For each of the following, how does it work, advantages/disadvantages
· Bailing
· Surging
· Overpumping
· Backwashing
· Air education
· High-velocity jetting - water or air
Why are polyphosphates sometimes used during well development?

Documentation
What kinds of records should be kept?
Sample description
Cuttings
Cores