DTD recently completed the installation of 450′ of in-situ chemical oxidation (ISCO) fluid injection screen at an east coast EPA Superfund Site. The location has a long and relatively deep plume that has migrated from the industrial site and beneath a public area. Use of vertical rigs to access the off-site portion of the plume is not an option, and even if a traditional rig could be brought in, the number of vertical wells necessary to treat the long plume would have been significant. The single-ended horizontal well placed 450′ of screen in direct communication with plume, 100 feet beneath the public area… this amount of screen in the plume would have required 15-20 vertical wells, and thousands of feet of vertical drilling.
The drilling was navigated using a gyroscopic steering tool (GST) to direct the borehole beneath the facility’s building and through a combined vertical and horizontal curve (see photo at left). After drilling through the complex curve with the GST, the well screen installation was completed by tracing the borehole with DTD’s patent pending Knock Off Drill Bit. This drilling technique allows locating the bore through the full drilled length, and then installing materials through the inside rod (reminiscent of setting a vertical well through hollow-stem augers) and engaging/releasing the drill bit. This allows precise placement of the well screen to the exact position that was designed.
DTD completed the design of the horizontal injection screen in order to insure even distribution of the ISCO solution along the full 450′ of length. These fluid injection screens typically have very low open areas and depending on the volume of fluid to be injected, the number of slots per foot may vary along the length.
For further information on this project or our ability to design and install long, deep blind wells, please call DTD directly.