A Guide To Water Well Casing and Screen Selection

Table of Contents

1.0.. INTRODUCTION .................................................................................................... 1
 
2.0 METHODS OF WELL CONSTRUCTION .............................................................. 2
2.1   Cable Tool ......................................................................................................... 2
2.2   Rotary ............................................................................................................... 3
 
3.0 GENERAL CASING AND SCREEN CONSIDERATIONS AND MATERIALS ....... 4
3.1   Strength and Durability ....................................................................................... 4
3.2   Handling and Maintenance ................................................................................. 4
3.3   Economy ........................................................................................................... 4
3.4   Steel .................................................................................................................. 5
3.5   Non-Ferrous Materials ........................................................................................ 5
 
4.0 MANUFACTURING PROCESSES AND END USE COMPARISONS .................... 6
4.1   Electric Resistance Welded ................................................................................ 6
4.2   Seamless ........................................................................................................... 6
4.3   Press Formed .................................................................................................... 6
4.4   Fabricated ......................................................................................................... 7
4.5   Spiral Weld ........................................................................................................ 7
4.6   Corrosion ........................................................................................................... 8
4.7   Dimensions ........................................................................................................ 8
4.8   Availability ........................................................................................................ 8
4.9   Substandard Pipe ............................................................................................... 8
 
5.0 CASING REQUIREMENTS .................................................................................... 9
5.1   Diameter ........................................................................................................... 9
5.2   Wall Thickness .................................................................................................. 10
5.3   Corrosion Resistance ......................................................................................... 12
5.4   Conductor Casing .............................................................................................. 14
 
6.0 WELL SCREEN REQUIREMENT .......................................................................... 15
6.1   Aperture Size and Internal Design ...................................................................... 15
6.2   Economy ........................................................................................................... 15
6.3   Entrance Velocity .............................................................................................. 16
6.4   Maintenance and Future Contingencies ............................................................... 16
 
7.0 SCREEN DESIGNS ................................................................................................. 17
7.1   Torch Cut Slots ................................................................................................. 17
7.2   Milled Slots ....................................................................................................... 17
7.3   Wire Wrap ........................................................................................................ 18
7.4   Bridge Slot ........................................................................................................ 20
7.5   Shutter Screen ................................................................................................... 21
 
8.0 END CONNECTIONS AND ACCESSORIES ....................................................... 22
8.1   Threaded and Coupled ...................................................................................... 22
8.2   Plain Ends ......................................................................................................... 22
8.3   Bell and Spigot End ........................................................................................... 23
8.4   Welding Collars ................................................................................................. 23
8.5   Stainless Steel to Carbon Steel Connections ....................................................... 23
8.6   Compression Sections ....................................................................................... 24
8.7   Landing Clamps ................................................................................................ 25
8.8   Casing Guides ................................................................................................... 26
8.9   Float Plates ....................................................................................................... 26
8.10   Diameter Reduction ......................................................................................... 27
8.11   Bottom Plugs ................................................................................................... 27
 
9.0 APPENDICIES AND TABLES ............................................................................... 28
9.1   Appendix I - Well Efficiency .............................................................................. 28
9.2   Appendix II - Formation Sampling, Filter Pack and Aperture Size Selection ....... 29
9.3   Appendix III - Analysis of Driving Casing with Cable Tool Equipment ............... 32
9.4   Appendix IV - Water Sampling for Chemical Analysis ....................................... 35
9.5   Table A - Head Losses Through Pipe ............................................................... 36
9.6   Table B - Physical Characteristics Blank Casing ................................................ 37
9.7   Table C - Specifications Steel Pipe ................................................................... 38
9.8   Table D - Specifications Steel ........................................................................... 39
9.9   Table E - Conversion Table .............................................................................. 40

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