DTD recently completed the installation of 5 single ended (blind) oxygen injection wells in Southern New England. The wells were part of a remediation system being used to mitigate two zones of contaminated groundwater migrating from a former gas station. And as is often the case at gas stations, the contamination had migrated beneath the adjacent street… a typically busy “Main Street”
The wells ranged in length from 120 to 238 feet, and were set with horizontal sections at either 20 or 40 feet below ground. Although these blind wells were relatively short in length, cobbly soils, many utilities and a very limited drilling footprint created a multitude of challenges.
Setting the drill rig over the second entry pit.
To minimize the surface footprint, all five wells were installed within two small entry pits. The restricted footprint also required the rig to be set at extreme angles to avoid fiber optic, water and sewer utilities. However, the biggest challenge was just drilling the wells. Relic concrete from the underground storage tank pads and abundant cobble required a varied drilling approach to the drilling to insure the well screens were placed in the targeted zone of contamination. Despite these nuances; ingenuity and “on-the-fly” field decisions allowed for the successful installation of these horizontal remediation wells.
Three of five recently installed oxygen injection wells.