Horizontal Drilling Techniques Offer Significant Advantages When Delineating Contamination

Horizontal drilling techniques offer significant advantages when delineating contamination, particularly on environmental projects where contamination exists in limited-access locations. Several tools can be applied to horizontal technologies to ensure the contamination at the site is well-defined, such as horizontal soil sampling and the use of down-hole sensing. Traditional vertical drilling methods may be limited by obstacles such as buildings, infrastructure, or underground utilities, which present substantial data gaps in the understanding of the conceptual site model. In contrast, horizontal drilling allows for the collection of soil samples beneath structures without the need for disruptive excavation or potential damage to existing facilities. This minimizes the impact on the surrounding environment, providing a less invasive and more efficient approach.

Soil Sampling by Navigating Horizontally

By navigating horizontally beneath buildings, drillers can target specific zones with precision, obtaining soil samples from areas that might be missed or difficult to access using conventional techniques. Where traditional vertical techniques may struggle to capture the lateral extent of contamination accurately, horizontal drilling allows for collection of samples along an aerial plane, enabling a more thorough assessment of the spread and distribution of contaminants beneath the surface. This spatially detailed information is crucial for effective remediation planning and execution.

Furthermore, the non-disruptive nature of horizontal drilling reduces the impact on the surface environment, particularly when it is critical that on-site business operations continue as usual. This is especially important when working in urban or developed areas, where minimizing disturbance and reducing restoration costs is critical. By avoiding extensive excavation, the technique helps preserve the integrity of the surrounding landscape and structures, contributing to a more sustainable and environmentally friendly approach to soil sampling and contamination delineation.

Conceptual Site Model Enhancement with Horizontal Sensing Technologies

Horizontal soil sampling is an indispensable tool when delineating contamination at a site; however, the site conceptual model can be enhanced further when used in tandem with down-hole sensing technologies. DTI is fortunate to have worked with TarGOST (Tar-specific Green Optical Screening Tool) creator Dakota Technologies on previous projects where developing a full understanding of contaminant delineation was paramount. The technology functions by advancing a sensor down the borehole to take high density fluorescence measurements, which rapidly assess NAPL concentrations in real time. These measurements can be used to make real-time design adjustments in the field and to develop high-resolution conceptual models during the post-analysis phase. When implemented simultaneously with horizontal soil sampling, a fully comprehensive understanding of the contaminant distribution throughout the site is achieved.

Case Study: Horizontal Soil Sampling for Contaminant Release Confirmation

Directional Technologies was approached by environmental consultants to utilize horizontal soil sampling to help confirm the potential release of contaminants at a site in the southeastern United States. A concrete-lined wastewater storage basin developed cracks, allowing the potential for contaminated media to drain into the subsurface. Samples had to be acquired from beneath the basin to confirm if, or to what extent, contamination had leaked. The alternative solution would have resulted in the costly and time-consuming process of draining and mobilizing a vertical drill rig into the basin, and coring through the thick concrete at multiple locations to achieve discreet samples. Instead, Directional Technologies drilled two horizontal bores from the upland areas adjacent to the basin and collected three soil samples from each alignment at a depth of just one foot below the concrete.

Results:

The use of horizontal sampling techniques provides a simple and accurate alternative to collecting subsurface soil samples from access-restricted areas. The horizontal sampling technology provided an alternative to the excessive costs and logistical feasibility associated with attempting to collect samples with vertical techniques.

How can the advantages offered by decades of technological advancement in horizontal wells benefit your project?  Call our horizontal remediation well experts at 1-877-788-4479 to discuss your current project needs or email us at drilling@directionaltech.com with questions, review case studies, and learn more.

Written By: Elliott Andelman, Professional Geologist