DTD is kicking off a project in the southeast to install several horizontal injection wells beneath a manufacturing facility once used as a Department of Energy assembly plant. The wells will be used to inject a solution to degrade groundwater contamination in-situ . The site is managed as part of DOE’s Legacy Management program and the facility is now occupied by tenants with sensitive operations limiting access to the area above the wells and requiring minimal disturbance.
The large plant building size makes traditional double-ended wells impractical, and the limited access to the building requires remote navigation of the bore. Traditionally this type of navigation is only available with larger drill rigs, however, site space does not allow for the use of a large rig. Therefore DTD recommended an approach that would require minimal intrusion into the building during site operations, and still be functional with a small drilling rig.
DTD selected the Digital Control Inc., Short Steering Tool (SST) to provide both remote and walkover locating capabilities while drilling under the building. The SST is a wireline guidance system that in addition to emitting a walkover signal, is calibrated to the earth’s magnetic field, which enables precision azimuth readings to be taken at the drill bit during drilling. This allows walkover locating of the drill bit when access is available, but also allows knowledge of the bit position even when walkover access is not available.
With groundwater contamination identified in multiple areas of the plant, eight horizontal remediation wells have been specified for the site. The number of wells and project duration made it a priority to minimize the site impact during the installation of the horizontal wells. The innovative combination of a small rig and a specialty locating system allow will these wells to be installed on a tightly controlled site with an small construction foot print and very limited disturbance to ongoing site activities.