Understanding how hydrocarbons actually move underground isn’t just technical—it’s financial strategy.
At a major refinery in the southern U.S., LNAPL had been observed in wells located more than 2 miles from the refinery at depths of 350 feet BGS. Installing a new well cost up to $180K due to the depth needed and, ultimately, provided limited insight on the mechanism driving the LNAPL migration across the large area of concern.
Aestus was brought in to update the conceptual site model (CSM) with our specialty GeoTrax Survey™ electrical resistivity imaging (ERI) combined with targeted confirmation drilling. The objectives: reduce uncertainty by mapping the subsurface features controlling contaminant migration and guide remediation with precision.
The results:
- Paleochannels mapped in detail – the high-permeability features that acted as primary LNAPL migration pathways were mapped across the domain (shown in the first image by blue, pink, and green lines connecting GeoTrax Survey™ images).
- Targeted drilling confirmed the discrete, impacted paleochannels (see MW-28 in the second image that was targeted from the ERI data and had LNAPL in the well shortly after drilling, whereas the previously drilled, untargeted, MW-C was not in a discrete paleochannel and had no LNAPL).
- 2D/3D visualization clarified the spatial distribution of hydrocarbons, refined the subsurface CSM, and facilitated groundwater models that informed which downgradient pumping wells were having the greatest influence on LNAPL migration.
- More than $20 Million saved on site characterization alone as a result of a “scan-first-drill-smart” approach
Focused characterization and remediation isn’t about doing more—it’s about doing the right work, in the right places, guided by the right data.