6. Annular Space & Sealing (this page left intentionally blank) 6. Annular Space & Sealing Chapter Table of Contents Chapter Table of Contents Chapter Description ......................................................................................................................................................................................... 6 Regulatory Requirements – Annular Space & Sealing of a New Well ..................................................................................................... 6 Relevant Sections – The Wells Regulation.............................................................................................................................................. 6 The Requirements – Plainly Stated .......................................................................................................................................................... 6 Well Record – Relevant Sections............................................................................................................................................................14 Best Management Practice – Report use of Centralizers .......................................................................................................... 15 Key Concepts ..................................................................................................................................................................................................16 The Annular Space ...................................................................................................................................................................................16 Best Management Practice – Annular Space Diameter ............................................................................................................. 16 Purpose of the Seal...................................................................................................................................................................................16 Examples of Improperly Sealed Annular Spaces.................................................................................................................................17 Requirements for Sealing Various Types of Wells ....................................................................................................................................18 Comparison of Bentonite and Cement Grouts..........................................................................................................................................27 Calculating Amount of Materials Required ................................................................................................................................................30 Mixing Bentonite Grout (Sealant)................................................................................................................................................................33 Best Management Practice – Mixing Bentonite Grout.............................................................................................................. 33 Techniques for Successful Mixing..........................................................................................................................................................33 Consequences of Poorly Mixed Bentonite Grout ...............................................................................................................................33 Mixing Cement or Concrete Grout (Sealant) .............................................................................................................................................34 Techniques for Successful Mixing..........................................................................................................................................................34 Best Management Practice – Techniques for Successful Mixing............................................................................................. 34 Consequences of Poorly Mixed Cement Grout...................................................................................................................................34 Grout Placement Requirements ...................................................................................................................................................................35 Best Management Practice – Sealing the Annular Space........................................................................................................... 35 Grout Placement – Inner String Method..............................................................................................................................................36 Best Management Practice – When Bentonite Grout Settles................................................................................................... 36 Grout Placement – Tremie Pipe Outside Casing Method .................................................................................................................39 Best Management Practice – Use of a Grout Pump.................................................................................................................. 39 Best Management Practice – Use of a Larger Diameter Tremie Pipe..................................................................................... 39 Best Management Practice – When Bentonite Grout Settles................................................................................................... 40 Grout Placement – Pouring Without Tremie Pipe .............................................................................................................................47 Grout Placement – Displacement Method...........................................................................................................................................47 Best Management Practice – When Bentonite Grout Settles................................................................................................... 47 Grout Placement – Double Plug Procedure.........................................................................................................................................49 Water Supply Wells – Requirements and Best Management Practices 3 Chapter Figures Chapter Description6. Annular Space & Sealing Best Management Practice – When Bentonite Grout Settles................................................................................................... 49 Grout Placement – When an Annular Space is Created by Use of a Driven Point.......................................................................50 Best Management Practice – A Method of Creating and Sealing Annular Space of a Well Constructed with the Use of a Driven Point .................................................................................................................................................................................. 51 Tools for Annular Space & Sealing..............................................................................................................................................................57 Chapter Figures Figure 6-1: Well Record – Relevant Sections – Annular Space...............................................................................................................14 Figure 6-2: Well Record – Relevant Sections – Construction Record ...................................................................................................15 Figure 6-3: Visible Open Annular Space Adjacent to Drilled Well Casing ...........................................................................................17 Figure 6-4: Visible Open and Large Annular Space Around Drilled Well ............................................................................................17 Figure 6-5: Visible Open Annular Space Below Pitless Adapter and Horizontal Waterline to the Bottom of the Casing...........17 Figure 6-6: Drilled Well in Overburden – Well Screens that are Artificially Packed or Naturally Developed................................19 Figure 6-7: Drilled Well – Without Well Screen........................................................................................................................................20 Figure 6-8: Examples of Drilled Wells in Bedrock ..................................................................................................................................21 Figure 6-9: Drilled Well in Overburden – Natural Development, Casing Pulled Back Exposing Screen Method ........................22 Figure 6-10: Bored Wells with Concrete Casing........................................................................................................................................23 Figure 6-11: Dug Well....................................................................................................................................................................................24 Figure 6-12: Driven Point Well ....................................................................................................................................................................25 Figure 6-13: Jetted Well .................................................................................................................................................................................26 Figure 6-14: Pumping Grout Down Tremie Pipe – Inside Casing.........................................................................................................37 Figure 6-15: Inner String Method of Grout placement............................................................................................................................38