Being prepared to deal with site-specific ground conditions can often make or break a remediation project and when it comes to horizontal remediation in high permeability soils, there are proven ways to ensure success in spite of some common misconceptions. When our clients approach us for help with a project, one of the first topics we are likely to discuss are the subsurface conditions. They sometimes have concerns about their sandy or otherwise highly permeability soil. Simply put, they are concerned if it is even possible to remediate their site. Happily, DTI has a long track record of success even in sandy soils.

  • Borehole collapse can be prevented, even in more difficult conditions such as fine sands.
  • Wells diameters can exceed 20 inches and well depths can exceed 100 feet.
  • Wells can be installed in a blind (single-entry) configuration with the well installation. terminating at the target depth at the end of the screen interval.
  • Sedimentation of the well can be prevented to ensure that the in-situ remedy can properly function.

 

What’s more,

  • Projects with high permeability soils often require fewer horizontal remediation wells due to the high radius of influence that can be achieved using Directional Technologies’ custom engineered site-specific well screen design.
  • Over a thousand horizontal remediation wells implementing a broad range of in-situ remedies (air sparge/SVE/injection/groundwater extraction/etc.) have been successfully installed by Directional Technologies over the last three decades.

 

Myths & Misconceptions of Horizontal Remediation in High Permeability Soils

There are various misconceptions surrounding the installation of horizontal wells in sands and other high permeability soils. These soils present a distinct set of challenges that must be managed using the appropriate drilling techniques in order to ensure that a horizontal remediation well can be successfully installed. With the proper tools and techniques, high permeability soils do not present any significant limitations to remediation well design and remedial construction. In fact, with their high transmissivity, these soils present an excellent opportunity for horizontal remediation, which allows the system to achieve the greatest possible radius of influence.

Myths and misconceptions include:

  • Horizontal wells are limited to small diameters and shallow depths. This is incorrect; DTI has successfully installed pipes in excess of 20” diameter.
  • Horizontal wells cannot be installed in a blind (single-entry) configuration with only one wellhead, they must be installed in an entry-exit configuration with a wellhead at the surface of each end of the well. This is incorrect; DTI has installed blind entry systems.
  • Horizontal wells cannot be properly developed. This is incorrect; proper techniques and experience result in a properly developed well.

It is true that high permeability soils present challenges such as maintaining borehole integrity and preventing fine particles from remaining in the well screen. However, through the application of the appropriate techniques, these challenges are commonly managed effectively. Drilling fluid must be the right type, the right consistency and introduced into the bore at the right pressure so that the drilling fluid can effectively stabilize the walls of the bore. An experienced driller monitors the annular pressure readings throughout the installation process and adjusts the process as necessary. Development techniques specific to high porosity soils must be used to ensure that any fine particles that may have entered into the well screens are sufficiently flushed. Well screen designs must be selected with the appropriate slot sizes and percentage of open area to ensure that fine particles from the formation do not inadvertently enter the well screen in the future.

Once these common challenges are managed, high permeability soils can allow for incredibly effective horizontal remediation solutions. The reality is that the misconceptions surrounding horizontal remediation in high permeability soils often stem from outdated knowledge or working with inexperienced horizontal remediation drillers.

Do your projects have a geological setting with high permeability soils where traditional vertical remediation wells may not be the best fit? Call our horizontal remediation well experts at 1-877-788-4479 to discuss your current project needs.