When thinking about the use of horizontal wells for environmental remediation projects, a common misconception is that the technology is only useful for large companies and/or large-scale projects. Contrary to this belief, horizontal well projects consisting of only a few short, shallow wells are consistently being completed for smaller businesses across the U.S.
One such example is the installation project completed in January by DTD in the San Francisco Bay Area. Groundwater and soil gas contamination originating from an off-site source migrated beneath a warehouse located in a dense packed industrial area. The majority of the contamination was located under office space inside a larger warehouse. Rather than trench through the floor inside the building, DTD was contracted to drill and install three horizontal soil vapor extraction (SVE) wells beneath the building.
For this project, DTD mobilized one of our smaller directional drill rigs (24,000 lbs rated rig) and a single pass mud system to the work site. The drilling operation set up on the north side of the building in a relatively small space (30’ x 60’). The wells were completed in blind (single entry) boreholes with the screen section depth roughly 5 feet below ground surface. Well materials consisted of 3 inch diameter, schedule 80 PVC screen and casing. Screen lengths averaged 169 feet and the total installed length of all three wells is 605 feet.
The installation of these wells, including mobilization, development (flushing and jetting of each well), and site cleanup took only five working days. The week following DTD’s installation, another contractor was on-site to connect the wells. From start to finish, it took only 2 weeks for the SVE remediation system to become operational. This project is just one example of how directional drilling can be utilized for smaller-scale remediation efforts where time, cost, and/or space can pose a challenge.